GSRP Usage Guide

Edition 1
Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

GSRP Usage Guide (Edition 1)

PrefaceThis document is intended to help deepen the understanding of GSRP (Gigabit Switch Redundancy Protocol), one of
ALAXALA’s own technologies. GSRP provides redundancy for switches in case of any failure, by securing acommunication path via another switch.
For the purpose of the effective design and establishment of GSRP systems, this document describes the operational
overview, the methods of configuration, the operational management, and the precautions regarding GSRP.

Related documents
・ AX-series product manual (http://www.alaxala.com/en/techinfo/manual/index.html)

Notes on using this document
The information in this document is based on the basic operations verified under the environment specified by
ALAXALA and does not guarantee operations regarding functionality, performance, and reliability under allenvironment requirements. Please understand that this document is intended to help with system configuration for our
products.
Unless otherwise stated, the OS software version as of the creation of this document is as shown below.
AX6300S series
Ver11.3
AX3630S series
Ver11.2.A
AX2430S
Ver11.2.A
Information in this document is subject to change without notice.
Export restrictions
If you export this guide, you must check and comply with all applicable laws, rules, and restrictions of Japan and anyother countries, such as Japan's Foreign Exchange and Foreign Trade Law and U.S. export control laws andregulations.

Trademarks- The ALAXALA name and logo are the trademarks or registered trademarks of ALAXALA Networks
Corporation.
- GSRP is a registered trademark of ALAXALA Networks Corporation.
- Ethernet is a trade name of Xerox Corporation in the U.S.
- Other company and product names in this manual are trademarks or registered trademarks of their respective
owners.
Conventions: The terms "Switch" and "switch"
The term Switch (upper-case "S") is an abbreviation for any or all of the following models:● AX6700S/AX6600S/AX6300S series switch● AX3600S, AX2400S series switch● AX2500S series switch● AX1200SA series switch
The term switch (lower-case "s") might refer to a Switch, another type of switch from the current vendor, or aswitch from another vendor. The context decides the meaning.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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GSRP Usage Guide (Edition 1)

Contents
Part 1 ............................................................................................................................5
Overview of GSRP .......................................................................................................5
1. What is GSRP? .......................................................................................................6
1.1

OVERVIEW OF GSRP.....................................................................................................................6

1.2

DESCRIPTION OF GSRP TERMS .....................................................................................................7

2. GSRP Features and Supported Specifications .......................................................8
2.1

GSRP FEATURES ..........................................................................................................................8

2.2

OVERVIEW OF LAYER 2 SYSTEM ...................................................................................................10

2.3

OVERVIEW OF LAYER 3 SYSTEM ...................................................................................................11

2.4

GSRP'S SUPPORTED SPECIFICATIONS ..........................................................................................12Part 2 ..........................................................................................................................13
Layer 2 Systems ........................................................................................................13
1. Operations of GSRP in Layer 2 .............................................................................14
1.1

LAYER 2 REDUNDANCY SWITCHING ...............................................................................................14

1.2

OPERATIONS IN CASE OF FAILURES ...............................................................................................14

2. Application Example of GSRP in Layer 2 ..............................................................16
2.1

CONFIGURATION OF A LAYER 2 SYSTEM ........................................................................................16

2.2

CONFIGURATION POINTS ..............................................................................................................16

2.3

CONFIGURATION EXAMPLE ...........................................................................................................19

3. Operational Management......................................................................................22
3.1

OPERATION COMMANDS ...............................................................................................................22

3.2

EXAMPLE OF GSRP FAILURE........................................................................................................23

4. Precautions ...........................................................................................................25
Part 3 ..........................................................................................................................27
Layer 3 Systems ........................................................................................................27
1. Operations of GSRP in Layer 3 .............................................................................28
1.1

LAYER 3 REDUNDANCY SWITCHING ...............................................................................................28

1.2

OPERATIONS IN CASE OF FAILURES ...............................................................................................28

2. Application Example 1 of GSRP in Layer 3 ...........................................................31
2.1

BASIC CONFIGURATION OF A LAYER 3 SYSTEM ..............................................................................31

2.2

CONFIGURATION POINTS ..............................................................................................................31

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GSRP Usage Guide (Edition 1)

2.3

CONFIGURATION EXAMPLE ...........................................................................................................35

3. Application Example 2 of GSRP in Layer 3 ...........................................................38
3.1

NETWORK SEPARATION SYSTEM WITH NETWORK PARTITION ..........................................................38

3.2

CONFIGURATION POINTS ..............................................................................................................38

3.3

CONFIGURATION EXAMPLE ...........................................................................................................40

4. Application Example 3 of GSRP in Layer 3 ...........................................................43
4.1

CONFIGURATION ON A BACKBONE NETWORK .................................................................................43

4.2

CONFIGURATION POINTS ..............................................................................................................43

4.3

CONFIGURATION EXAMPLE ...........................................................................................................45

5. Operational Management......................................................................................51
5.1

OPERATION COMMANDS ...............................................................................................................51

5.2

EXAMPLE OF GSRP FAILURE........................................................................................................52

6. Precautions ...........................................................................................................55
Appendix: Configuration Files......................................................................................57

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GSRP Usage Guide (Edition 1)

Part 1
Overview of GSRP
This part describes the overview, features, and supported specifications of GSRP.

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GSRP Usage Guide (Edition 1)

1.

What is GSRP?

1.1

Overview of GSRP

GSRP (Gigabit Switch Redundancy Protocol) is ALAXALA’s proprietary technology for a redundancy switching
functionality that provides a redundancy configuration for two GSRP switches, which allows communication tocontinue via another switch even if one switch encounters a line failure or a malfunction.
Spanning Tree Protocol (STP), which provides network redundancy, can be utilized as redundancy functionality in
Layer 2, while VRRP provides the redundancy of default gateways in Layer 3. In contrast, GSRP provides Layer 2
redundancy and Layer 3 redundancy at the same time as a single feature.

LANswitchExchange
control frames

GSRP
group
SwitchFailurePath
before a failureLANswitchPathafter a failure

Figure 1.1-1 Overview of GSRP

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GSRP Usage Guide (Edition 1)

1.2

Description of GSRP terms

The table below explains the terms relating to GSRP.
Table 1.2-1 Description of GSRP terms
No.
1

Term
GSRP switch

Description
A switch that is equipped with L2 and L3 redundancy through GSRP functionality, andis operating as a master or backup with the GSRP function enabled
A GSRP switch operating as master. A master controls its VLAN groups so that itbrings all VLANs in the groups to a forwarding state, and it provides communications
based on the registration information of MAC addresses.
A GSRP switch operating as backup. A backup controls its VLAN groups so that itbrings all VLANs in the groups to a blocking state, resulting in no forwarding,
although it sends and receives GSRP control frames and L2 control frames.
A backup becomes a master when a failure occurs in its adjacent master switch.
A lower-level switch of a GSRP switch that is able to acknowledge GSRP Flushrequest frames from the GSRP switch and to clear the MAC address table.
A lower-level switch of a GSRP switch that is unable to acknowledge GSRP Flushrequest frames from the GSRP switch (A third-party product).
An instance of GSRP; it comprises up to two GSRP switches and one or more GSRP
aware/unaware
A logical group that groups multiple VLANs; they constitute a unit of master andbackup switching in a GSRP group. Load balancing for each VLAN is achieved byusing such VLAN groups.
There are two types of GSRP control frames: GSRP Advertise for informationexchange between a master and its backup; and GSRP Flush request, which informs
neighboring GSRP aware switches of the switching of a master and removes the MAC
address entries.
A type of GSRP control frame; used for information exchange between a master and its
backup via a direct link between switches (master and backup).

2

GSRP master

3

GSRP backup

4

GSRP aware

5

GSRP unaware

6

GSRP group

7

VLAN group

8

GSRP control frame

9

GSRP Advertise

10

GSRP Flush request

A type of GSRP control frame: used to inform GSRP aware switches of the switchingof a master or backup, and request the removal of the MAC address entries.

11

direct link

12

GSRP-managed VLAN

A connection link between a GSRP master and backup. It is essential for GSRP. A
direct link is used for sending and receiving GSRP control frames (GSRP Advertise). It
is recommended to make two or more lines as a direct link so as not to stop thecommunication between a master and its backup.
A VLAN that sends and receives GSRP control frames; it must be configured toconnect with a direct link and to have communication ports with GSRP aware
switches.

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GSRP Usage Guide (Edition 1)

2.

GSRP Features and Supported Specifications

2.1

GSRP features

GSRP has the following benefits, and also achieves L2 and L3 redundancy as a single feature.
(1) Avoiding an infinite loop
In some redundancy protocols such as STP, there is the possibility that a backup device might automatically shift to amaster state if no normality checking frame is received from its partner, leading to communication failure.
In GSRP, in contrast, when GSRP backup becomes a master due to failure or for any other reason, it waits for its
master to shift to the backup state before shifting to the GSRP master state. This prevents the two GSRP switches fromtransitioning to master at the same time, eliminating the risk of loops.

Problems with STP
Unreachable BPDU causes all switches to be the root
bridge!
All ports are forwarding.
L2 loop (broadcast storm) emerges!

Excessive loads on lines and devices
cause communication failure.

Fatal!!

Broadcaststorm

Communication
failure

GSRP generates no loop, since a backup shifts to the master state
after its partner shifts to backup!
Figure 2.1-1 The problem of overlapping masters in STP(2) Layer 3 linkage
A network composed of STP needs linkage with VRRP to secure Layer 3 redundancy.
In contrast, GSRP implements Layer 2 and 3 redundancy as a single functionality. Therefore, GSRP has theadvantage of linkage with Layer 3 and of easy-to-use operational management.
(3) Restrictions in the range of sending control frames
In GSRP, all control frames will be sent and received by specified VLANs in order to restrict the range of sending
control frames and to prevent them from being sent to unnecessary points.
This mechanism achieves stable operations even under high loads, since no control frame flows through any dataline in a normal operation.

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8

GSRP Usage Guide (Edition 1)(4) Load balancing among VLAN groups as a unit
In GSRP, the states (master and backup) are managed for each VLAN group. It is possible to achieve trafficbalancing by establishing a load-balanced configuration with multiple VLAN groups.

Exchange GSRP Advertises(Send information on VLAN
groups together)

Path of
VLAN group A

Path of
VLAN group B

GSRP group
GSRP switch A

GSRP switch B

Acts as master in VLAN
group A, backup in VLAN
group B

VLAN
Group AVLAN 10VLAN 20VLAN 30

Acts as backup in VLAN
group A, master in VLAN
group B

VLAN
Group BVLAN 40VLAN 50VLAN 60

Figure 2.1-2 GSRP's load balancing

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GSRP Usage Guide (Edition 1)

2.2

Overview of Layer 2 system(1) Overview of Layer 2 redundancy
GSRP is composed of two switches; which one acts as master will be determined by the control frames exchanged
between the two GSRP switches. Only a GSRP master can establish communication; the GSRP backup does notcommunicate.
Exchanges control
frames between two
GSRP switches
Only lines
connected with themaster are open.

GSRP

2.2-1 Overview of the Layer 2 system(2) Comparison between GSRP and STP
A comparison between GSRP and STP (rapid-PVST: IEEE802.1w) in Layer 2 systems is shown in the table below.
Table 2.2-1 Comparison between GSRP and STP
No.
1

Item
Risk of L2 loop2

Switching speed

3
4

5

GSRP
 Controlled only by GSRP switches, no riskof L2 loop
 Faster than STP

STP Broadcast storm is possible; high risk of
L2 loop.
 Slow to recover from root bridge down

Applicability forlarge systems
Stability under highloads

 No limit to the number of VLANs

 The number of VLANs is limited.

 Stable at high loads since no control frame
flows through data lines

Connection withthird-party devices

 ALAXALA proprietary functionality sono connectivity with third-party devices
 Outside of GSRP systems, third-party
devices can be connected as GSRP
unaware.

 High loads in data lines can impede
control frames, likely to cause traffic
failure.
 Reciprocal connection with standardcompliant devices is supported.

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GSRP Usage Guide (Edition 1)

2.3

Overview of Layer 3 system(1) Overview of Layer 3 redundancy
GSRP supports Layer 3 redundancy switching functions as well as Layer 2 redundancy switching. In Layer 3
redundancy switching, two GSRP switches make a default gateway redundant by sharing the same IP address and
MAC address.
In case of failure in a GSRP master, the GSRP backup shifts to master and automatically inherits the IP address tokeep connected.
Two GSRP switches
share the same IP and
MAC address.

Upstream IP network

GSRP

2.3-1 Overview of the Layer 3 system(2) Comparison between GSRP and STP-VRRP
A comparison between GSRP and STP-VRRP in Layer 3 systems is shown in the table below. Note that the tablecompares the GSRP Layer 3 redundancy switching with the combination of VRRP and STP.
Table 2.3-1 Comparison between GSRP and STP-VRRP
No.
1

Item
Layer 2 + Layer 3
redundancy
Switching speed

GSRP One function achieves Layer 3 linkage;easy to manage.
 Faster than STP-VRRP

STP-VRRP Necessary to link two functions (STPand VRRP) Depends on the switching speed of STP

3

Stability under highloads

 Stable at high loads since no control
frame flows through data lines

4Connection withthird-party devices

 ALAXALA proprietary functionality sono connectivity with third-party devices
 Outside of GSRP systems, third-party
devices can be connected as GSRP
unaware.

 Likely to become unstable due toincreased packets controlling STP and
VRRP Reciprocal connection with standardcompliant devices is supported.

2

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GSRP Usage Guide (Edition 1)

2.4

GSRP's supported specifications

The specifications on the support of GSRP of the AX series are listed in the table below. Note that AX2400S does notsupport Layer 3 redundancy switching, while AX1200S supports only GSRP aware functionality. The AX3600S
series and AX6000S series support the same functional specifications, though there is a difference between theaccommodation conditions.
Table 2.4-1 GSRP's supported specifications
No.
1
2
3
4

Function
AX1200S
Layer 2 redundancy switchingN
Layer 3 redundancy switchingN
GSRP aware
Y
Number of GSRP
N
groups per device
5
Maximum number of theN
Switches composing a GSRP
group
6
Maximum number of VLAN
N
groups per GSRP group7
Maximum number of VLANs
N
per VLAN group
8
Transmission interval of GSRP
N
Advertise frames
9
Retention time for GSRP
N
Advertise frames
10 Load balancing
N
11 Backup fixationN
12 Port resettingN
13 Sequential switchingN
prevention
14 VLAN group-only controlNfunctionality
15 Ports not controlled by GSRPN
Legend Y : Supported N : Not supported

AX2400S
YNY
1AX3600SYYY
1AX6300SYYY
1AX6600SYYY
1AX6700S
Y
Y
Y
1

2

2

2

2

2

64

64

128

128

128

1024

1024

4095

4095

4095

0.5-60seconds
1-120
secondsYYYY

0.5-60seconds
1-120
secondsYYYY

0.5-60seconds
1-120
secondsYYYY

0.5-60seconds
1-120
secondsYYYY

0.5-60seconds
1-120
seconds
Y
Y
Y
Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

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GSRP Usage Guide (Edition 1)

Part 2
Layer 2 Systems
This part describes the operation, application example, operational management, and precautions regarding
GSRP in a Layer 2 system.

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GSRP Usage Guide (Edition 1)

1.

Operations of GSRP in Layer 2

1.1

Layer 2 redundancy switching

GSRP allows you to achieve Layer 2 network redundancy (loop avoided). Unlike STP, GSRP is controlled by the
information exchanges between two switches, thus resulting not only in faster switching but also in applicability tolarge networks.
VLAN 10
GSRP Advertise frames
exchanged between master andbackup

GSRP switch A

GSRP switch B
Direct link

GSRP group
MasterBackupBlocking

Forwarding
GSRP-managed
VLAN

VLAN 10Figure 1.1-1 Operations of GSRP
A pair of two GSRP switches constitutes a GSRP group, where in normal operation, one is the master and the otheris the backup. A direct link between the GSRP switches is one of the essential elements of a GSRP system. Via thelink, the switches exchange GSRP Advertise frames to control the system. In GSRP, GSRP Advertise frames areused to switch the states of the master and backup. A GSRP switch in a master state sends forward the frames from
specified VLAN groups, while the other backup switch blocks them.
To restart communications immediately after GSRP switches shift between master and backup states requires the
MAC address table entries retained by surrounding switches to be cleared at the same time the GSRP switches shift.
GSRP supports the following two methods of removing the MAC address table entries of surrounding switches.



1.2

Transmission of GSRP Flush request frames
GSRP switches send the control frames, called GSRP Flush request frames, to surrounding switches torequire them to clear their MAC address table entries.
Port resetting
Port resetting functionality disconnects surrounding switches with GSRP switches for a short time. This isused when surrounding switches are GSRP unaware.

Operations in case of failures(1) Operations at the time of link failure
A link failure in any link between the GSRP master and the switches managed by it will be followed by the series ofswitching operations shown below.
1) GSRP switch A detects a link-down with the switches managed by it, decreasing the number of active
ports;
2) GSRP switch A shifts to the backup state;
3) GSRP switch B, which currently has the right to be GSRP master as GSRP Advertise says the number ofactive ports is greater than that of GSRP switch A, shifts to a wait-for-master state;4) GSRP switch A informs GSRP switch B that A is currently in a backup state;

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GSRP Usage Guide (Edition 1)
5) GSRP switch B shifts to master;6) GSRP switch B sends a GSRP Flush request to the GSRP-managed VLANs to force GSRP aware switches
to clear their MAC address tables, and;
7) To force GSRP unaware switches to clear their MAC address table, GSRP switch A activates theport-resetting function to reset the ports (link-down).
Backup to
wait-for-master

Master to
backup
GSRP switch A

Wait-for-masterto master

Backup

GSRP switch B

GSRP switch A

GSRP switch B

FailureFailure

GSRP unaware

GSRP
aware
GSRP advertise
GSRP Flush request

GSRP aware

GSRP
unawareReceives GSRP Flush request
and clears the MAC address

Temporary link-down
forcibly clears the MAC

Figure 1.2-1 Operations at the time of link failure(2) Operations at the time of master switch failure
Any failure of a GSRP master switch will be followed by the series of switching operations as shown below.
1. If GSRP switch A fails, GSRP switch B detects the failure through the absence of GSRP Advertise from A,
and shifts to a No neighbor state;
2. If the operation mode in case of direct link down detection is set to manual, a disconnection will be maintained
until the user executes a switching command;
3. If the operation mode in case of direct link-down detection is set to direct-down, GSRP switch B
automatically shifts to master, since GSRP Advertise from A is timed out and the direct link line is in alink-down state;
4. GSRP switch B sends a GSRP Flush request to the GSRP-managed VLANs to force GSRP aware switches toclear their MAC address tables, and;5. The MAC address tables of GSRP unaware switches are cleared through the link-down associated with the
failure of GSRP switch A.
Backup to No
neighbor

Master to
down
GSRP switch A

Down

GSRP switch B

GSRP switch A

No neighbor tomaster

GSRP switch B

FailureFailureDetect Advertisetimeout
GSRP aware

GSRP unaware

GSRP advertise
GSRP Flush request

Receives GSRP Flush request
and clears the MAC address

GSRP aware

GSRP unaware

MAC address cleared throughthe link-down of GSRP switch
A

Figure 1.2-2 Operations at the time of master device failure

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GSRP Usage Guide (Edition 1)

2.

Application Example of GSRP in Layer 2This chapter explains the key points and operation of GSRP configuration in a Layer 2 system.

2.1

Configuration of a Layer 2 system
An example of an application of GSRP into a Layer 2 system is shown below.
In this example system, two VLANs are divided into separate VLAN groups to achieve load balancing.
VLAN 10 in VLAN group 1 communicates via GSRP switch A, while VLAN 20 in VLAN group 2 communicates
via GSRP switch B. Thus, the loads of communication are distributed.

VLAN group 2
backupVLAN group 1
master
GSRP switch A
AX6304S

System administration terminal

GSRP switch B
AX6304S

Direct link

VLAN group 2master

GSRP group 1

VLAN group 1
backupThird-party L2 switch

AX2430S
VLAN group 1
VLAN 10VLAN 10

Core switches

VLAN group 2
VLAN 20VLAN 20VLAN 10

Access switches

VLAN 20

Figure 2.1-1 Load-distributed GSRP configuration

2.2

Configuration points

In this example, there are six key points to establish a GSRP system achieving Layer 2.
(1) Disabling the spanning tree
(2) Configuration of a direct link(3) Efficient load distribution with load-balancing for each VLAN group(4) Optimization of configuration parameters(5) Difference of settings between GSRP aware switches and GSRP unaware switches(6) Setting of the remote control port
The details of each point will be explained later.

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GSRP Usage Guide (Edition 1)(1) Disabling the spanning tree
To establish GSRP, it is necessary to terminate the spanning tree in advance. No GSRP switch can activate GSRP
without disabling the spanning tree.

(2) Configuration of a direct link

A redundant direct link is recommended.
If you set up direct-down mode, where direct link failure detection automatically shifts a backup to master,
redundant direct link through link aggregation between different NIFs is recommended to reduce the riskthat two GSRP switches become master at the same time.

Attach a direct link only to GSRP-managed VLANs.
In Layer 2 systems, a direct link sends and receives only GSRP Advertise frames from GSRP-managed
VLANs. No other VLAN setting for data transfer is required.

(3) Efficient load distribution with load-balancing for each VLAN group
As shown in Figure 2.1-1, if you establish multiple VLAN groups, you can establish a load-balanced configurationfor each VLAN group by giving different priority to them. The larger the number is, the higher its priority is.
In this example, if you set the priority between VLAN groups as:
GSRP switch A: VLAN group 1 > VLAN group 2
GSRP switch B: VLAN group 1 < VLAN group 2Then, GSRP switch A will be the master in VLAN group 1, while GSRP switch B will be the master in VLAN group2, thus enabling load distribution.

(4) Optimization of configuration parametersOptimization of link debounce time
Set up the link debounce time as short as possible within the range that maintains the link stable. This
reduces the switching time of GSRP at the time of link failure.

Optimization of the transmission interval and the retention time of GSRP Advertise frames
Set up the transmission interval and the retention time of GSRP Advertise frames. The shorter the time is,the shorter the switching time is, at the expense of higher CPU loads. If high loads frequently occur to theCPU, set a longer time to these parameters, although it depends on system status.
Parameters on GSRP
Advertise frames
advertise-interval
advertise-holdtime

Default setting

Recommended

1 second
5 seconds

0.5 seconds
3 seconds

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17

GSRP Usage Guide (Edition 1)(5) Difference of settings between GSRP aware switches and GSRP unaware switches
Access switches that surround GSRP switches include GSRP aware switches supported by the AX-series switches,or GSRP unaware third-party switches. Although both are available, we recommend GSRP aware switches for thesystem design.
The following differences exist in the configuration and features between GSRP aware switches and GSRP
unaware switches.


GSRP aware switches
This type of switch needs the same VLAN setting as GSRP-managed VLANs. Specify GSRP-managed
VLAN as the connection port with GSRP switches.
AX-series products support GSRP aware functionality. In addition, GSRP Flush request is available for the
faster recovery of connection and switching time.



GSRP unaware switches
To use GSRP unaware switches requires port-resetting functionality for two GSRP switches. The
functionality enables third-party switches to connect to a GSRP system. In shifting two GSRP switches fromand to master and backup states, each port of a switch shifting to backup connected to a GSRP unaware
switch is temporality shut down (link-down). Switching generally takes a longer time than GSRP aware
switches.
Use this functionality when neighboring switches are not AX series devices.

(6) Setting of the remote control port
When GSRP is activated, all VLANs are controlled by GSRP. GSRP blocks all ports of any VLAN that does notbelong to any VLAN group.
If you want to use telnet or SNMP to remotely manage the switches that use GSRP, use any of the three methods
shown below.
The management port is used in the configuration example. The management port can always be used forcommunication regardless of GSRP states.
Use of the management port.
Only AX6000S series have the port.
Set up a port not subject to GSRP-management (gsrp exception-port).
It can at any time be used for communication regardless of GSRP states (master/backup).
Set up GSRP VLAN group-only control (gsrp limit-control).
This setting makes only VLANs belonging to any VLAN group subject to the control of GSRP. Any VLAN
not belonging to any VLAN group can always be used for communication.

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GSRP Usage Guide (Edition 1)

2.3

Configuration example

An example of a logical configuration is illustrated below. This section shows an example of each device based on
the logical configuration.

System administration terminal
Management port

GSRP switch B
C2: AX6304S

GSRP switch A
C1: AX6304S
VLAN 2

MSU (1 sys)
3/1 NIF3 3/24

4/1

VLAN 2,10,20

F1:AX2430S

NIF4 4/24
VLAN 10,20

0/1
0/2
VLAN 2,10,20
VLAN 10
0/5

VLAN 20
0/6

VLAN 10VLAN 20

MSU (1 sys)
3/1

NIF3 3/24

No.

Core
switches

4/1 NIF4 4/24
VLAN 10,20

VLAN 2,10,20

0/1
0/2
VLAN 10,20

F2:
3rd-party
L2 switch

172.16.255.10

VLAN 10
0/5

VLAN 20
0/6

VLAN 10VLAN 20

Accessswitches

Management purpose
IP：172.16.255.1/24
Management port
IP：172.16.255.2/24
Management port

GSRP switch A
GSRP switch B

Figure 2.3-1 A logical configuration of GSRP
(1) Configuration of the core switch (GSRP switch)
Configuration of C1 (AX6304S)
Disabling the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled in default in AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,10,20

Configures the VLAN to be applied.

Configuration of the GSRP
(config)# gsrp 1(config-gsrp)# gsrp-vlan 2

Configures the GSRP group IDs.
Configures the GSRP-managed VLANs.

Configuration of the direct link(config)# interface range gigabitethernet 3/24, gigabitethernet
4/24(config-if-range)# channel-group 1 mode on(config)# interface port-channel 1(config-if)# gsrp 1 direct-link

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Configures a channel group containing different NIFs to makethe direct link redundant. (Configuration point (2))
Configures Port channel 1 as GSRP1's direct link.

19

GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)
Configuration of VLAN groups and master/backup(config)# gsrp 1(config-gsrp)# vlan-group 1 vlan 10(config-gsrp)# vlan-group 2 vlan 20(config-gsrp)# vlan-group 1 priority 200(config-gsrp)# vlan-group 2 priority 100

Configures a VLAN group.
Joins VLAN 10 in VLAN group 1 and VLAN 20 in VLAN
group 2.
Configures the priorities among VLAN groups.
Assigns a higher priority to VLAN group 1 than Switch C2.
Assigns a lower priority to VLAN group 2.
(Configuration point (3))

Configuration of GSRP parameters(config-gsrp)# advertise-interval 0.5(config-gsrp)# advertise-holdtime 3(config-gsrp)# no-neighbor-to-master direct-down

Configures the GSRP Advertise frames' transmission interval
and retention time. (Configuration point (4))
Configures the direct link failure detection function. Lets
backup automatically shift to master when there is a failure in
the direct link.
1

Configuration of the physical port interfaces
Configuration of the ports(config)# interface range gigabitethernet 3/1, gigabitethernet
3/24, gigabitethernet 4/1, gigabitethernet 4/24
(config-if-range)# link debounce time 0(config)# interface gigabitethernet 3/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,10,20(config)# interface gigabitethernet 4/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 10,20(config-if)# gsrp 1 reset-flush-port(config)# interface port-channel 1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2

Sets as small a link-down detection time as possible.
(Configuration point (4))
1

Configures each port.
The access switch connected to Port 3/1 is GSRP aware. Sets
up this port as the trunk port, and assign the GSRP-managed
VLAN 2, along with VLAN 10 and VLAN 20, for datatransfer.
The access switch connected to Port 4/1 is GSRP unaware.
Sets up this port as the trunk port, and assign VLAN 10 and
VLAN 20 for data transfer. Enable port resetting since the
GSRP unaware switch is connected.
(Configuration point (5))
1

Configures Port channel 1, set up as the direct link, as the trunk
port and assign GSRP-managed VLAN.

Configuration on remote management of the devices(config)# interface mgmt 0(config-if)# ip address 172.16.255.1 255.255.255.0(config)# line vty 0 2

Configures the port for management as the Management port.
Assign an IP address.
(Configuration point (6))
Permits telnet log-in (up to three at a time)

Note: The configuration of Switch C2 is the same as that of Switch C1 except for the priority of GSRP VLAN groups and the IP
address for remote control. For details, see the attached configuration file.

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20

GSRP Usage Guide (Edition 1)(2) Configuration of the access switches
Configuration of F1 (AX2430S)
Disabling the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled as default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,10,20

Configures the VLAN to be applied.

Configuration of the ports(config)# interface range gigabitethernet 0/1-2(config-if-range)# link debounce time 0(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,10,20

Configures each port.
Configures Port 0/1-2 as the trunk port, and assign the
GSRP-managed VLAN 2, along with VLAN 10 and VLAN
20, for data transfer.

(config)# interface gigabitethernet 0/5(config-if)# switchport mode access(config-if)# switchport access vlan 10

Configures each port connected to a terminal.
Configures each VLAN assigned to each port as an accessport.

(config)# interface gigabitethernet 0/6(config-if)# switchport mode access(config-if)# switchport access vlan 20
Note: Switch F2 (from a third party) requires no settings on the GSRP-managed VLAN to be configured. The other settings arenormally the same as those of F1.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

21

GSRP Usage Guide (Edition 1)

3.

Operational Management

This chapter describes operational management, including the operation commands used for establishing a
GSRP-enabled network and how to isolate the causes of failures.

3.1

Operation commands

GSRP operation commands are to be shown below.
(1) Operational commands to check for the state of GSRP show gsrp [detail]
Displays a summary of the state of GSRP; using [detail] (optional) shows the detailed information.
An example of the results of the show gsrp [detail] command in a GSRP switch
C1# show gsrp detail
Date 2010/05/20 14:11:16 UTC

GSRP ID: 1
Local MAC Address: 0012.e2a0.f600
Neighbor MAC Address: 0012.e2a0.3600
Total VLAN Group Counts : 2
GSRP VLAN ID: 2
Direct Port: 3/24,4/24
Limit Control: Off
GSRP Exception Port
: No Neighbor To Master: direct-down
Backup Lock: disable
Port Up Delay: 0
Last Flush Receive Time : Forced Shift Time: Layer 3 Redundancy: Off
Virtual Link ID: -Advertise Hold Time
Advertise Hold Timer
Advertise Interval
Selection Pattern
VLAN Group ID
12... [GSRP configuration status]
Displays the detail of the GSRP of the switch

Local
: 3
: 3
: 0.5
: ports-priority-mac

Local State
MasterBackup

Neighbor
3
0.5
ports-priority-mac…[GSRP master/backup status]
Displays the GSRP Advertise timer value andselection method of the master/backup…[VLAN group status]
VLAN group 1 uses this (C1) as the master.
VLAN group 2 uses the opposite (C2) as themaster.

Neighbor State
BackupMaster show gsrp aware
Displays the information on the GSRP aware switches; this command must be executed on any GSRP
aware switch.
An example of the results of the show gsrp aware command executed in a GSRP aware
switchshow gsrp aware
Date 2010/05/20 14:12:14 UTC
Last MAC Address Table Flush Time
GSRP Flush Request Parameters :GSRP ID : 1
VLAN Group ID : 1
Source MAC Address : 0012.e2a0.f600: 2010/05/20 14:06:00
Port : 0/1

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

…[GSRP aware status]
The last time it flushed the Mac
Address table…Information on the last GSRP that flushed the Mac
Address table (The port that received the GSRP
ID/VLAN group ID/flush frames)

22

GSRP Usage Guide (Edition 1)(2) Operation commands to control GSRP states set gsrp master
Shifts the backup (No neighbor) state to the master; this command is valid only in the backup (Noneighbor) state.
 clear gsrp port-up-delay
In a VLAN assigned to a VLAN group, this command promptly updates a port in the link-up state to an
active port, without waiting for the delay time configured with the port-up-delay configurationcommand.
(3) Operation command to reset abnormal GSRP states restart gsrp
Restart GSRP program after issuing the confirmation message for restart. All VLANs belonging to any
GSRP VLAN groups stop receiving any frames, resulting in the termination of the communication.

3.2

Example of GSRP failureThis section introduces an example where a GSRP switch encounters a line failure. See Figure 2.3-1 for detailed
configuration.

(1) Normal operation status
GSRP group 1 has two VLAN groups; VLAN group 1 sees GSRP switch A as the master, while VLAN group 2sees GSRP switch B as the master. The GSRP states of both core switches are shown below.
Normal operation status of the GSRP switch
C1# show gsrp
Date 2010/05/20 14:11:16 UTC

C2# show gsrp
Date 2010/05/20 14:11:30 UTC

GSRP ID: 1
Local MAC Address: 0012.e2a0.f600
Neighbor MAC Address: 0012.e2a0.3600
Total VLAN Group Counts : 2
Layer 3 Redundancy: Off

GSRP ID: 1
Local MAC Address: 0012.e2a0.3600
Neighbor MAC Address: 0012.e2a0.f600
Total VLAN Group Counts : 2
Layer 3 Redundancy: Off

VLAN Group ID
1
2

Neighbor State
BackupMasterVLAN Group ID
1
2

Type Protocol
Port GSRP
1:Port GSRP
1:Port GSRP
1:Port GSRP
1:

C2# show vlan list
Date 2010/05/20 14:15:59 UTC
VLAN counts:4
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 44 VLAN0001
2 Down0/ 3/ 3 VLAN0002
10 Down
0/ 2/ 2 VLAN0010
20 Up
2/ 2/ 2 VLAN0020

Local State
MasterBackupC1# show vlan list
Date 2010/05/20 14:15:44 UTC
VLAN counts:4
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 44 VLAN0001
2 Down0/ 3/ 3 VLAN0002
10 Up
2/ 2/ 2 VLAN0010
20 Down
0/ 2/ 2 VLAN0020

-(-)
-(-)
1(M)
2(B)

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

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Local State
BackupMasterNeighbor State
MasterBackupType Protocol
Port GSRP
1:Port GSRP
1:Port GSRP
1:Port GSRP
1:

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

23

-(-)
-(-)
1(B)
2(M)

GSRP Usage Guide (Edition 1)(2) Operations in case of GSRP failure
If GSRP switch A, a core switch, encounters a line failure, the GSRP master and backup will be switched. In thiscase, a line failure on GSRP switch A (Switch C1), where VLAN group 1 is the master, results in the situation
where neighboring GSRP switch B (Switch C2) has more active ports than GSRP switch A, causing GSRP switch
B to shift to master.
Shown below are the messages issued from each device when GSRP switch A encounters a line failure.
Messages from each device in case of a line failure+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Messages issued from Core switch (GSRP switch A) C1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
05/20 14:12:31 E4 PORT GigabitEthernet3/1 25011101 1350:a00000004120 Error detected on the port.
… Port 3/1 encountered a line failure.
05/20 14:12:31 E3 VLAN 20130008 0700:000000000000 GSRP 1 VLAN group 1 : state transitioned from Master to Backup, because thenumber of active ports was less than neighbor's.
… GSRP switching occurred. VLAN group 1, now holding smaller number of active ports than neighbor (C2),has shifted from master to backup.
05/20 14:12:31 E4 VLAN 25100002 0700:000a00000000 VLAN (10) Status is Down.
… VLAN10 in VLAN group 1 has gone down.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Messages issued from Core switch (GSRP switch B) C2+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
05/20 14:12:33 E3 VLAN 20130003 0700:000000000000 GSRP 1 VLAN group 1 : state transitioned to Master, because the number of active
ports was more than neighbor's.
… GSRP switching occurred. VLAN group 1, now holding larger number of active ports than neighbor (C1),
has shifted to master.
05/20 14:12:33 E4 VLAN 25100001 0700:000a00000000 VLAN (10) Status is Up.
… This device (C2) has become master of VLAN group 1, the VLAN 10 has gone up.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Messages issued from Access Switch F1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
05/20 14:19:05 E4 PORT GigabitEthernet0/1 25011101 1350:70020000e125 Error detected on the port.
05/20 14:19:06 E3 VLAN 20130015 0700:000000000000 GSRP aware : MAC Address Table entry cleared, because GSRP flush request received
on port 0/2, GSRP 1 VLAN group 1 Source MAC address 0012.e2a0.3600.
… GSRP Flush request frames are received from GSRP switch B (C2), and MAC address table is cleared.

If GSRP switch A (Switch C1) encounters a line failure, VLAN group 1 of GSRP switch B (Switch C2) shifts frombackup to master. VLAN group 2 keeps the state of master, resulting in two master VLAN groups being generated.
The example below shows the operation status of GSRP switches.
Operation status of GSRP switches after a failure
C1# show gsrp
Date 2010/05/20 14:21:18 UTC

C2# show gsrp
Date 2010/05/20 14:21:30 UTC

GSRP ID: 1
Local MAC Address: 0012.e2a0.f600
Neighbor MAC Address: 0012.e2a0.3600
Total VLAN Group Counts : 2
Layer 3 Redundancy: Off

GSRP ID: 1
Local MAC Address: 0012.e2a0.3600
Neighbor MAC Address: 0012.e2a0.f600
Total VLAN Group Counts : 2
Layer 3 Redundancy: Off

VLAN Group ID
1
2

VLAN Group ID
1
2

Local State
BackupBackupC1# show vlan list
Date 2010/05/20 14:21:20 UTC
VLAN counts:4
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 44 VLAN0001
2 Down0/ 2/ 3 VLAN0002
10 Down
0/ 1/ 2 VLAN0010
20 Down
0/ 1/ 2 VLAN0020

Neighbor State
MasterMaster

Port
Port
Port
Port

Type Protocol
GSRP
1: -(-)
GSRP
1: -(-)GSRP
1: 1(B)
GSRP
1: 2(B)

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Local State
MasterMaster

C2# show vlan list
Date 2010/05/20 14:21:35 UTC
VLAN counts:4
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 44 VLAN0001
2 Down0/ 3/ 3 VLAN0002
10 Up
2/ 2/ 2 VLAN0010
20 Up
2/ 2/ 2 VLAN0020

Neighbor State
BackupBackup

Port
Port
Port
Port

Type Protocol
GSRP
1: -(-)
GSRP
1: -(-)GSRP
1: 1(M)
GSRP
1: 2(M)

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

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GSRP Usage Guide (Edition 1)

4.

Precautions(1) Compatibility with the spanning tree
No spanning tree function (single spanning tree, PVST+, multiple spanning trees) is compatible with GSRP in one
device.
(2) Using port resetting in a load-balanced configuration
When you configure port resetting to one physical port that is shared with multiple VLAN groups, a shift of one of
the VLAN groups from master to backup causes a communication interrupt, since the port is temporarily in alink-down state, although no other VLAN groups shift from master.
If you want to avoid the temporary link-down while using port resetting, make sure that multiple VLAN groups do
not share one physical port.
(3) Applying GSRP to a newly built network
Take the following measures to avoid frame loops when configuring GSRP into a network.


Shutdown ports during configuration
Prior to configuring GSRP, set the ports of the opposite switch to shutdown to set it in a down state. Afterthe configuration, wait for the stable-state configuration of GSRP before starting operation.
Start and set up GSRP switches one by one
Of the two GSRP switches constituting a GSRP group, start and configure one switch, and make sure it has
shifted to backup before starting and configuring the other GSRP switch.

(4) In case of high CPU load
A heavy load placed on a CPU might cause the discarding of some of the received GSRP Advertise frames or mightcause processing delay, leading to the output of timeout messages or state shifts. If such a state takes placefrequently, set up a larger value to the transmission interval and retention time of the GSRP Advertise frames.

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25

GSRP Usage Guide (Edition 1)(This page is intentionally blank)

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26

GSRP Usage Guide (Edition 1)

Part 3Layer 3 Systems
This part describes the operation, application examples, operational management, and precautions regarding
GSRP in a Layer 3 system.
The following three application examples are explained later in this part.

<Application example 1>
Basic configuration of a Layer 3 system<Application example 2>
Network separation system with Network Partition<Application example 3>
Configuration of a backbone network

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27

GSRP Usage Guide (Edition 1)

1.
1.1

Operations of GSRP in Layer 3
Layer 3 redundancy switching

GSRP supports Layer 3 redundancy switching as well as Layer 2 redundancy switching at the same time.
Layer 3 redundancy switching is implemented by two GSRP switches sharing the same IP address and MAC
address to create a redundant default gateway. By applying GSRP to a default gateway for PCs, the communication
path from the PCs to an upstream IP network becomes redundant.
If a default gateway device encounters a failure, the other one can take over the same IP address and MAC address
to continue the communication through the default gateway from the PCs.

Upstream IP network
Path in thenormal state

Path after
failureOut-of-range of GSRP
control

GSRP switch A

GSRP switch B

Direct link

GSRP group

VLAN 10
IP : 10.0.0.1
MAC : aVLAN 10
IP : 10.0.0.1
MAC : aFailureMaster after a failure

VLAN group
VLAN 10

Default gateway
10.0.0.1

VLAN 10VLAN 10Figure 1.1-1 Layer 3 redundancy switching
The basic configuration of Layer 3 redundancy switching is listed below.
 A pair of two redundant switches implements the redundancy of the default router and the Layer 2 network.
 Both GSRP switches have the same IP address and MAC address (no need to re-learn a PC's ARP)
 Assign the same IP address to one VLAN shared with the two GSRP switches. The GSRP master
implements IP forwarding as the default gateway, with the shared VLAN in an up state, while the GSRP
backup does not implement IP forwarding, with the shared VLAN in a down state.
 Use a GSRP-proprietary virtual MAC address. Virtual addresses must be different between different VLAN
groups.

1.2

Operations in case of failures(1) Operations at the time of link failure
In case of a link failure between a GSRP master and any of its switches in a Layer 3 system, the switchover
operations listed below will occur.
1) GSRP switch A detects such link-down with the switches managed by it, decreasing the number of Active
ports;
2) GSRP switch A shifts to the backup state;
3) GSRP switch B, which currently has the right to be GSRP master as GSRP Advertise says the number ofActive ports is greater than that of GSRP switch A, shifts to a wait-for-master state;4) GSRP switch A informs GSRP switch B that A is currently in a backup state;

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28

GSRP Usage Guide (Edition 1)
5) GSRP switch B shifts to master;6) GSRP switch B sends a GSRP Flush request to force GSRP aware switches to clear their MAC addresstables, and;7) Communication is kept active through GSRP switch B, according to the IP routing setting of GSRP switch B.
VLAN 100VLAN 100

Master to
backupBackup to
wait-for-master

BackupWait-for-masterto master

GSRP switch A

GSRP switch B

GSRP switch A

GSRP switch B

VLAN 50VLAN 50

FailureFailureVLAN 10VLAN 10

GSRP advertise

VLAN 10VLAN 10Path

GSRP Flush request

Figure 1.2-1 Operations at the time of link failure(2) Operations at the time of master switch failure
In case of a failure in the GSRP master switch in a Layer 3 system, the switchover operations listed below will
occur.
1. If GSRP switch A fails, GSRP switch B detects the failure through the absence of GSRP Advertise from A,
and shifts to No neighbor;
2. If the operation mode in case of direct link down detection is set to manual, a disconnection will be maintained
until the user executes a switching command;
3. If the operation mode in case of direct link-down detection is set to direct-down, GSRP switch B
automatically shifts to master, since GSRP Advertise from A is timed out and the direct link line is in alink-down state;
4. GSRP switch B sends a GSRP Flush request to the GSRP-managed VLANs to force GSRP aware switches toclear their MAC address tables, and;5. The MAC address tables of GSRP unawares are cleared through the link-down associated with the failure of
GSRP switch A.
VLAN 100VLAN 100Down

No neighbor tomaster

GSRP switch A

GSRP switch B

Backup to No
neighbor

Master to
down

GSRP switch B

GSRP switch A

FailureFailureVLAN 50VLAN 10VLAN 50VLAN 10VLAN 10VLAN 10Path

GSRP advertise
GSRP Flush request

Figure 1.2-2 Operations at the time of master device failure

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29

GSRP Usage Guide (Edition 1)(3) Operations in case of link failure with an upstream IP network
In case of link failure with an upstream IP network in a Layer 3 system, the following operations will take place.
1. Since the link port of GSRP switches and the upstream IP network is out of the range of GSRP control, nostate shift of GSRP takes place. Therefore, GSRP switch A remains the master, and GSRP switch B remains
the backup.
2. An inter-VLAN communication network on the direct link secures another available communication path.
3. Communication is kept active through the direct link, according to the IP routing setting of GSRP switch A
and B.

VLAN 100VLAN 100

Failure detected in the
upstream IP network(out-of-range of GSRP control)

FailureFailure
GSRP switch B

GSRP switch A

GSRP switch A

VLAN 50
BackupBackupMasterVLAN 10

GSRP advertise

GSRP switch B
VLAN 50

MasterVLAN 10An inter-VLAN
communication
network on the direct
link secures anotherpath.

VLAN 10VLAN 10Path

GSRP Flush request

Figure 1.2-3 Operations in case of a line failure with an upstream IP network

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30

GSRP Usage Guide (Edition 1)

2.
2.1

Application Example 1 of GSRP in Layer 3
Basic configuration of a Layer 3 system

Figure 2.1-1 illustrates a redundant system with Layer 3 GSRP. GSRP can replace a redundant system composedof STP and VRRP without changing any physical configuration.
This configuration example assumes that an existing set of two switches comprising a redundant system will bereused to form a system through GSRP Layer 3 redundancy.

System administration terminal

GSRP switch B
AX6304S

GSRP switch A
AX6304S

Inter-VLAN communication network

GSRP

Core switches

VLAN group 1
VLAN 10
AX2430S

VLAN group 2
VLAN 20
AX2430S

AX2430S
Access switches

VLAN 10VLAN 20VLAN 10VLAN 20VLAN 10VLAN 20

Figure 2.1-1 An example of GSRP Layer 3 configuration
This example system will use an inter-VLAN communication network, and IP routing will be implemented throughpassing Layer 3 forwarding between VLANs through the direct link. Such a basic configuration allows you to use
multiple VLAN groups, enabling traffic load distribution.

2.2

Configuration points

There are 10 points to configure GSRP in this example.
Items (7) through (10) are characteristic of Layer 3 systems.
(1) Disabling the spanning tree
(2) Configuration of a direct link(3) Efficient load distribution with load-balancing for each VLAN group(4) Optimization of configuration parameters(5) Difference in the settings between GSRP aware switches and GSRP unaware switches(6) Setting of the remote control port
(7) Use GSRP group IDs from 1 to 4.
(8) Enable Layer 3 redundancy switching.
(9) Setting of the link between GSRP switches(10) Assign the same IP address to two GSRP switches.
The details of each point are explained below.

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31

GSRP Usage Guide (Edition 1)(1) Disabling the spanning tree
To establish GSRP, it is necessary to terminate the spanning tree in advance. No GSRP switch can activate GSRP
without disabling the spanning tree.

(2) The direct link is recommended to be redundant.
If you use direct-down mode, where direct link failure detection automatically shifts a backup to master, redundant
direct link through link aggregation between different NIFs is recommended to reduce the risk that two GSRP
switches become master at the same time.

(3) Efficient load distribution with load-balancing for each VLAN group
If you establish multiple VLAN groups, you can establish a load-balanced configuration for each VLAN group by
giving a different priority to them. The larger the number is, the higher its priority is.
In this example, if you set the priority between VLAN groups as:
GSRP switch A: VLAN group 1 > VLAN group 2
GSRP switch B: VLAN group 1 < VLAN group 2Then, GSRP switch A will be the master in VLAN group 1, while GSRP switch B will be the master in VLAN
group 2, thus enabling load distribution.

(4) Optimization of configuration parametersOptimization of link debounce time
Set up the link debounce time as short as possible within the range that maintains the link stable. This
reduces the switching time of GSRP at the time of link failure.

Optimization of the transmission interval and the retention time of GSRP Advertise frames
Set up the transmission interval and the retention time of GSRP Advertise frames. The shorter the time is,the shorter the switching time is, at the expense of higher CPU loads. If high loads frequently occur on theCPU, set these parameters to a longer time, although it depends on the system status.
Parameters on GSRP
Advertise frames
advertise-interval
advertise-holdtime

Default setting

Recommended

1 second
5 seconds

0.5 seconds
3 seconds

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32

GSRP Usage Guide (Edition 1)(5) Difference in the settings between GSRP aware switches and GSRP unaware switches
Access switches that surround GSRP switches include GSRP aware switches, AX-series switches, or GSRP
unaware, third-party switches. Although both are available, we recommend designing the system with GSRP aware
switches.
The following differences exist in the configuration and features between GSRP aware switches and GSRP unaware
switches.


GSRP aware switches
This type of switch needs the same VLAN setting as GSRP-managed VLANs. Specify GSRP-managed
VLAN as the connection port with GSRP switches.
AX-series products support GSRP aware functionality. In addition, GSRP Flush request is available for the
faster recovery of connection and switching time.



GSRP unaware switches
To use GSRP unaware switches requires port-resetting functionality for two GSRP switches. The
functionality enables third-party switches to connect to a GSRP system. In shifting two GSRP switchesfrom and to master and backup, each port of the switch shifting to backup connected to a GSRP unaware
switch is temporality shut down (link-down). Switching generally takes longer time than GSRP aware
switches.
Use this functionality when neighboring switches are not AX series devices.

(6) Setting of the remote control port
When GSRP is activated, all VLANs are controlled by GSRP. GSRP blocks all ports of any VLAN that does notbelong to any VLAN group.
If you want to use telnet or SNMP to remotely manage the switches that use GSRP, use any of the three methods
shown below.
Management port is used in the configuration example. Management port can always be used for communication
regardless of GSRP states.


Use the management port.
Only the AX6000S series has this port.
Set up a port not subject to GSRP-management (gsrp exception-port).
It can at any time be used for communication regardless of GSRP states (master/backup).
Set up GSRP VLAN group-only control (gsrp limit-control).
This setting makes only VLANs belonging to any VLAN group subject to the control of GSRP. Any VLAN
not belonging to any VLAN group can always be used for communication.

The remaining items are characteristic of Layer 3 systems.
(7) Use GSRP group IDs from 1 to 4.
In using Layer 3 redundancy switching, you need to set up GSRP group IDs of 1 to 4. With any group ID of five or
larger, Layer 3 redundancy switching cannot be configured.

(8) Enable Layer 3 redundancy switching.
To make a redundant GSRP system with a Layer 3 system, you need to enable Layer 3 redundancy switching in the
GSRP settings. Enable it in both GSRP switches.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

33

GSRP Usage Guide (Edition 1)(9) Setting of the link between GSRP switches
To make a load-distributed Layer 3 system, the following configurations are necessary toward the direct link.


Set up an inter-VLAN communication network as a direct link.
To interconnect between two GSRP switches (master and backup), set up an inter-VLAN communication
network and IP routing to the link between the GSRP switches.
Exclude the direct link port from the subject of GSRP control.
Select ports that are not under GSRP control (gsrp exception-port) or limit GSRP control to VLAN
groups (gsrp limit-control).

(10) Assign the same IP address to both GSRP switches.
Assign the same IP address to both GSRP switches of the VLANs under the control of GSRP. The VLAN
interfaces of the GSRP master are in an up state, while those of the GSRP backup are in a down state.
Note that neither GSRP-managed VLANs nor VLANs for remote control are included.

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GSRP Usage Guide (Edition 1)

2.3

Configuration example

An example of a logical configuration is illustrated below. This section shows an example of each device based on
the logical configuration.
not subject to
GSRP-management with VLAN
group-only control

Management port

GSRP switch A
C1: AX6304S

VLAN group 1
masterVLAN 2,30

MSU (1 sys)
3/1 3/2 3/24

4/1

0/1
0/2
VLAN 2,10,20
VLAN 10
0/5

VLAN 10
No.

4/24

3/1

VLAN
IP

F2:
AX2430S

VLAN 20

Control

C1: 172.16.255.1
C2: 172.16.255.2

VLAN 2-VLAN group 2master

3/2

3/24

4/1

4/24

VLAN 2,10,20

VLAN 20
0/6Management
purpose172.16.255.10

MSU (1 sys)

VLAN 2,10,20

F1:AX2430S

System administration terminal

GSRP switch B
C2: AX6304S

0/1
0/2
VLAN 2,10,20
VLAN 10
0/5

VLAN 10VLAN group 1
VLAN 10VLAN 10：192.168.10.0/24

F3:AX2430S

VLAN 20
0/6

VLAN 20

0/1
0/2
VLAN 2,10,20
VLAN 10
0/5

VLAN 10

Data communication
VLAN group 2
VLAN 20VLAN 20：192.168.20.0/24

VLAN 20
0/6

VLAN 20

Direct link
VLAN 30VLAN 30：30.0.0.0/24

Figure 2.3-1 A logical configuration of GSRP application example 1(1) Configuration of the core switch (GSRP switch)
Configuration of C1 (AX6304S)
Disabling the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled by default in AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,10,20,30

Configures the VLAN to be applied.

Configuration of the GSRP
(config)# gsrp 1(config-gsrp)# gsrp-vlan 2

Configures the GSRP group IDs.
Assigns 1 to 4 GSRP group IDs.
(Configuration point (7))
Configures the GSRP-managed VLANs.

Setting on Layer 3 redundancy switching(config-gsrp)# layer3-redundancy

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Sets up Layer 3 redundancy switching.
(Configuration point (8))
Layer 3 can only be used with GSRP group IDs of 1 to 4.

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GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)
Configuration of the direct link(config)# interface range gigabitethernet 3/24, gigabitethernet
4/24(config-if-range)# channel-group 1 mode on(config)# interface port-channel 1(config-if)# gsrp 1 direct-link

Configures a channel group containing different NIFs to makethe direct link redundant.
(Configuration point (2))
Configures Port channel 1 as GSRP1's direct link.

Configuration of master/backup (load-distributed)(config)# gsrp 1(config-gsrp)# vlan-group 1 vlan 10(config-gsrp)# vlan-group 2 vlan 20(config-gsrp)# vlan-group 1 priority 200(config-gsrp)# vlan-group 2 priority 100

Configures a VLAN group.
Joins VLAN 10 in VLAN group 1 and VLAN 20 in VLAN
group 2.
Configures the priorities among VLAN groups.
Assigns a higher priority to VLAN group 1 than Switch C2.
Assigns a lower priority to VLAN group 2.
(Configuration point (3))

Configuration of the GSRP parameters(config-gsrp)# advertise-interval 0.5(config-gsrp)# advertise-holdtime 3(config-gsrp)# no-neighbor-to-master direct-down(config)# gsrp limit-control

Configures the GSRP Advertise frames' transmission interval
and retention time. (Configuration point (4))
Configures the direct link failure detection function. Let backup
automatically shift to master when there is a failure in the direct
link.
Enables limiting GSRP control to VLAN-group VLANs inorder to exclude the direct link from GSRP control.
(Configuration point (9))

Configuration of the physical port interfaces(config)# interface range gigabitethernet 3/1-2, gigabitethernet
3/24, gigabitethernet 4/1, gigabitethernet 4/24
(config-if-range)# link debounce time 0(config)# interface range gigabitethernet 3/1-2, gigabitethernet
4/1(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,10,20(config)# interface port-channel 1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,30

Sets as small a link-down detection time as possible.
(Configuration point (4))
Configures each port.
The connected access switches of port 3/1-2 and 4/1 are
GSRP aware. Set up this port as the trunk port, and assign the
GSRP-managed VLAN 2, along with VLAN 10 and VLAN
20, for data transfer.
Configures Port channel 1, set up as the direct link, as the trunk
port and assign GSRP-managed VLAN 2 and the inter-VLAN
communication path of VLAN 30.

Configuration of VLAN interfaces(config)# interface vlan 10(config-if) ip address 192.168.10.1 255.255.255.0(config)# interface vlan 20(config-if) ip address 192.168.20.1 255.255.255.0(config)# interface vlan 30(config-if) ip address 30.0.0.1 255.255.255.0

Assigns an IP address to VLAN 10.
Assigns the same IP address to Switch C2.
Assigns an IP address to VLAN 20.
Assigns the same IP address to Switch C2.
(Configuration point (10))
Assigns an IP address to VLAN 30.
Assigns a different IP address of the same subnet to Switch C2.

Configuration of IP routing(config)# ip route 192.168.20.0 255.255.255.0 30.0.0.2

As the next hop of the static route 192.168.20.0/24, assign
the adjacent gateway 30.0.0.2.
(Configuration point (9))

Configuration on remote management of the devices(config)# interface mgmt 0(config-if)# ip address 172.16.255.1 255.255.255.0

Sets up the Management port for remote control purpose.
Assigns an IP address.
(Configuration point (6))
Permits telnet log-in (up to three at a time)(config)# line vty 0 2
Note: The configuration of Switch C2 is the same as that of Switch C1, except for the IP address and IP routing assigned to VLAN
30, the priority of GSRP VLAN groups, and the IP address for remote control. For details, see the attached configuration file.

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36

GSRP Usage Guide (Edition 1)(2) Configuration of the access switches
Configuration of F1 (AX2430S)
Disabling the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled as default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,10,20

Configures the VLAN to be applied.

Configuration of the ports(config)# interface range gigabitethernet 0/1-2(config-if-range)# link debounce time 0(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,10,20

Configures each port.
Configures Port 0/1-2 as the trunk port, and assign the
GSRP-managed VLAN 2, along with VLAN 10 and VLAN
20, for data transfer.

(config)# interface gigabitethernet 0/5(config-if)# switchport mode access(config-if)# switchport access vlan 10

Configures each port connected to a terminal.
Configures each VLAN assigned to each port as an accessport.

(config)# interface gigabitethernet 0/6(config-if)# switchport mode access(config-if)# switchport access vlan 20
Note: The configuration of Switch F2 is equivalent to that of Switch F1.

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37

GSRP Usage Guide (Edition 1)

3.

Application Example 2 of GSRP in Layer 3

3.1

Network separation system with Network Partition

Figure 3.1-1 illustrates a GSRP redundant system utilizing Network Partition. In this configuration example, GSRP isapplied to two independent networks utilizing Network Partition.
Network Partition*1 establishes multiple logical networks with a simple physical configuration by combining VRF(Virtual/VPN Routing and Forwarding) to logically separate Layer 3 functionality and VLAN, the logical network
technology of Layer 2.

GSRP switch A
AX6304S

GSRP switch B
AX6304S
Core switches

System administration terminal

System administration terminal

GSRP

AX2430S

AX2430S

AX2430S
Access switches

Partition 1: Network 1

Partition 2: Network 2

Figure 3.1-1 A network separation system utilizing Network Partition*1

For details on Network Partition, refer to the following solution guide.
AX series Network Partition Solution Guide [Basic]

This configuration example takes advantage of GSRP to assign a different GSRP master to different VLANs used bypartitions. This enables load distribution in a partition basis, eliminates the consideration of routing between GSRP
switches, and allows you to configure a system easily with minimum settings.

3.2

Configuration points
There are 3 points to configure GSRP in this example.
(1) The same points as the configuration points of Application Example 1 Basic configuration ofa Layer 3 system(2) Setting of the link between GSRP switches(3) Streamline the settings by sharing VLANs used in Network Partition with GSRP.
The details of each point are explained below.

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38

GSRP Usage Guide (Edition 1)(1) Configuration points of Layer 3 systems

The following configuration points are the same as those of Application Example 1 Basic configuration of a Layer 3
system. For details, see the configuration points of the above example.
Configuration points of Application Example 1 Basic configuration of a Layer 3 system: Disable STP.
 A direct link is recommended to be redundant.
 Load distribution on VLAN group basis
 Optimization of configuration parameters Difference in the settings between GSRP aware switches and GSRP unaware switches Setting of the remote control port
 Assign 1 to 4 for GSRP IDs.
 Enable Layer 3 redundancy switching.
 Setting of GSRP switches-> There is a difference in this setting. For details see configuration point (2).
 Assign the same IP address to the one between GSRP switches(2) Setting of the link between GSRP switches

This configuration example assumes a system where two partitions are completely separated without any
communication between VRF. Therefore, it is not necessary to set up the inter-VLAN communication network of thedirect link and routing associated with the network.

(3) Streamline the settings by sharing VLANs used in Network Partition with GSRP.

GSRP can configure VLANs belonging to any VLAN group without depending on VRF, allowing you to configure asystem in consideration of load balancing. However, you need to carefully design the routing between the GSRP
switches and other settings.
When combining GSRP and Network Partition to use two separated partitions, making VLANs used in VRF belong toa GSRP VLAN group in the same partition eliminates the need to set up the routing between GSRP switches, resulting
in simpler settings.
This is another benefit of a more understandable and logical configuration and operation for the switching of GSRP.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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GSRP Usage Guide (Edition 1)

3.3

Configuration example

An example of a logical configuration is illustrated below. This section shows an example of each device based on
the logical configuration.
GSRP switch A
C1: AX6304S

GSRP switch B
C2: AX6304S
VLAN 2

MSU (1 sys)

System administration terminal

MSU (1 sys)
System administration terminal

172.16.255.10
3/1 3/2 3/24
VLAN

VRF10
masterF1:
AX2430S

VLAN

0/1
0/2
VLAN 2,10,11
VLAN 10
0/5

VLAN 10

4/1

4/24
VLAN

F2:
AX2430S

VLAN 11
0/6

3/2

VLAN

3/24

VLAN 20
0/6

VLAN 12VLAN
IPManagement
purposeControl

C1: 172.16.255.1
C2: 172.17.255.1

VLAN 2-

VRF20
master

0/1
0/2
VLAN 2,21,22
VLAN 21
0/5

VLAN 20172.17.255.10

4/24

VLAN

F3:
AX2430S

VLAN 21

Partition 1: Network 1

No.

4/1

VLAN

0/1
0/2
VLAN 2,12,20
VLAN 12
0/5

VLAN 11

3/1

VLAN 22
0/6

VLAN 22

Partition 2: Network 2

Network 1： VRF10

Data communication
Network 2： VRF20

VLAN 10, 11, 12
VLAN 10: 192.168.10.0/24
VLAN 11: 192.168.11.0/24
VLAN 12: 192.168.12.0/24

Direct link

VLAN 20, 21, 22
VLAN 20: 192.168.20.0/24
VLAN 21: 192.168.21.0/24
VLAN 22: 192.168.22.0/24-

Figure 3.3-1 A logical configuration of GSRP application example 2(1) Configuration of the core switch (GSRP switch)
Configuration of C1 (AX6304S)
Disabling the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled in default in AX series.
(Configuration point (1))

Configuration of the VRF(config)# vrf mode gsrp-enable-ipv4-ipv6
PSP will be restarted automatically when the selected mode
differs from current mode.
Do you wish to change mode (y/n): y(config)# vrf definition 10(config)# vrf definition 20

Sets up VRF as associated with GSRP.
(PSP restart is confirmed; type "y" if OK)

Enables VRF 10.
Enables VRF 20.

VLAN configuration(config)# vlan 2,10-12,20-22

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Configures the VLAN to be applied.

40

GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)
Configuration of the GSRP
(config)# gsrp 1(config-gsrp)# gsrp-vlan 2

Configures the GSRP group IDs.
Assigns 1 to 4 GSRP group IDs.
(Configuration point (1))
Configures the GSRP-managed VLANs.

Configuration on Layer 3 redundancy switching(config-gsrp)# layer3-redundancy

Sets up Layer 3 redundancy switching.
(Configuration point (1))
Layer 3 can only be used with GSRP group IDs of 1 to 4.

Configuration of the direct link(config)# interface range gigabitethernet 3/24, gigabitethernet
4/24(config-if-range)# channel-group 1 mode on(config)# interface port-channel 1(config-if)# gsrp 1 direct-link

Configures a channel group containing different NIFs to makethe direct link redundant.
(Configuration point (1))
Configures Port channel 1 as GSRP1's direct link.

Configuration of master/backup(config)# gsrp 1(config-gsrp)# vlan-group 1 vlan 10-12(config-gsrp)# vlan-group 2 vlan 20-22(config-gsrp)# vlan-group 1 priority 200(config-gsrp)# vlan-group 2 priority 100

Configures a VLAN group.
Joins VLAN 10-12 in VLAN group 1 and VLAN 20-22 in
VLAN group 2.
Configures the priorities among VLAN groups.
Assigns a higher priority to VLAN group 1 than Switch C2.
Assigns a lower priority to VLAN group 2.
(Configuration point (1))

Configuration of the GSRP parameters(config-gsrp)# advertise-interval 0.5(config-gsrp)# advertise-holdtime 3(config-gsrp)# no-neighbor-to-master direct-down

Configures the GSRP Advertise frames' transmission interval
and retention time. (Configuration point (1))
Configures the direct link failure detection function. Lets
backup automatically shift to master when there is a failure in
the direct link.

Configuration of the physical port interfaces(config)# interface range gigabitethernet 3/1-2, gigabitethernet
3/24, gigabitethernet 4/1, gigabitethernet 4/24
(config-if-range)# link debounce time 0(config)# interface gigabitethernet 3/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,10-11(config)# interface gigabitethernet 3/2(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,12,20(config)# interface gigabitethernet 4/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,21-22(config)# interface port-channel 1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2

Sets as small a link-down detection time as possible.

Configures each port.
Connecting to the GSRP aware access switch
Sets Port 3/1 as the trunk port, set VLAN 2 for GSRP control,and set VLAN 10 and VLAN 11 for data transfer.

Sets Port 3/2 as the trunk port, set VLAN 2 for GSRP control,and set VLAN 12 and VLAN 20 for data transfer.

Sets Port 4/1 as the trunk port, set VLAN 2 for GSRP control,and sets VLAN 21 and VLAN 22 for data transfer.
Sets Port channel 1, set up as the direct link, as the trunk port,
and sets GSRP-managed VLAN 2.
There is no need to set up an inter-VLAN communication
network.
(Configuration point (2))

Configuration of VLAN interfaces(config)# interface vlan 10(config-if) vrf forwarding 10(config-if) ip address 192.168.10.1 255.255.255.0
config)# interface vlan 11(config-if) vrf forwarding 10(config-if) ip address 192.168.11.1 255.255.255.0

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

VLAN 10 is used by VRF 10.
Assigns an IP address to VLAN 10.
Assigns the same IP address to Switch C2.
VLAN 11 is used by VRF 10.
Assigns an IP address to VLAN 11.
Assigns the same IP address to Switch C2.

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GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)
config)# interface vlan 12(config-if) vrf forwarding 10(config-if) ip address 192.168.12.1 255.255.255.0(config)# interface vlan 20(config-if) vrf forwarding 20(config-if) ip address 192.168.20.1 255.255.255.0
config)# interface vlan 21(config-if) vrf forwarding 20(config-if) ip address 192.168.21.1 255.255.255.0
config)# interface vlan 22(config-if) vrf forwarding 20(config-if) ip address 192.168.22.1 255.255.255.0

VLAN 12 is used by VRF 10.
Assigns an IP address to VLAN 12.
Assigns the same IP address to Switch C2.

VLAN 20 is used by VRF 20.
Assigns an IP address to VLAN 20.
Assigns the same IP address to Switch C2.
VLAN 21 is used by VRF 20.
Assigns an IP address to VLAN 21.
Assigns the same IP address to Switch C2.
VLAN 22 is used by VRF 20.
Assigns an IP address to VLAN 22.
Assigns the same IP address to Switch C2.
(Configuration point (3))

Configuration on remote management of the devices(config)# interface mgmt 0(config-if)# ip address 172.16.255.1 255.255.255.0

Sets up the management port for remote management.
Assigns an IP address.
(Configuration point (1))
Permits telnet log-in (up to three at a time)(config)# line vty 0 2
Note: The configuration of Switch C2 is the same as that of Switch C1 except for the priority of GSRP VLAN groups and the IP
address for remote control. For details, see the attached configuration file.

(2) Configurations of access switches
Configurations of F1 (AX2430S)
Suppression of the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled as default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,10-11

Configures the VLAN to be applied.

Configuration of the physical port interfaces(config)# interface range gigabitethernet 0/1-2(config-if-range)# link debounce time 0(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,10-11(config)# interface range gigabitethernet 0/5(config-if-range)# switchport mode access(config-if-range)# switchport access vlan 10(config)# interface range gigabitethernet 0/6(config-if-range)# switchport mode access(config-if-range)# switchport access vlan 11

Sets up the link-down detection time to minimum.
(Configuration point (1))
Ports 0/1-2 connect to C1 and C2, respectively.
Sets up the port as the trunk port, set up VLAN 2 for GSRP
control, and set VLAN 10 and VLAN 11 for data transfer.
Port 0/5 connects to the terminal.
Sets up this port as the access port, and set up VLAN 10 for datatransfer.
Port 0/6 connects to the terminal.
Sets up this port as the access port, and set up VLAN 11 for datatransfer.

Note: Switches F2 and F3 have the same setting as F1, except for the VLANs to be handled.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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GSRP Usage Guide (Edition 1)

4.
4.1

Application Example 3 of GSRP in Layer 3
Configuration on a backbone network

Figure 4.1-1 illustrates a configuration example of a backbone network utilizing GSRP.
This configuration uses GSRP to control the link between access switches in each floor, along with the core switches.
The backbone upstream network is connected via IP routing. The upstream IP network utilizes GSRP's Layer 3
redundancy switching, while IP routing is implemented with static routing or dynamic routing.

Data center

AX3630S

System administration terminal

Server-handlingswitches

IP network
GSRP switch A
AX6304S

GSRP switch B
AX6304S

GSRP

AX2430S

Core switches

AX2430S

Floor 1

Floor 2

AX2430S

Accessswitches

Floor 3Figure 4.1-1 GSRP backbone network

4.2

Configuration points
There are 3 points to configure GSRP in this example.
(1) The same points as the configuration points of Application Example 1 Basic configuration ofa Layer 3 system(2) Settings on the side of the upstream network(3) port-up-delay is recommended if using OSPF.
The details of each point are explained below.

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43

GSRP Usage Guide (Edition 1)(1) Configuration points of Layer 3 systems
The following configuration points are that same as those of Application Example 1 Basic configuration of a Layer 3
system. For details, see the configuration points of the above example.
Configuration points of Application Example 1 Basic configuration of a Layer 3 system
 Disable STP.
 A direct link is recommended to be redundant.
 Load distribution on VLAN group basis
 Optimization of configuration parameters Difference in the settings between GSRP aware switches and GSRP unaware switches Setting of the remote control port
 Assign 1 to 4 for GSRP IDs.
 Enable Layer 3 redundancy switching.
 Setting of GSRP switches Assign the same IP address to the one between GSRP switches(2) Settings on the side of the upstream network
The points regarding upstream network settings are as follows:

Exclude the connection port to the upstream network from the subject of GSRP control.
Specify it as not under GSRP control (gsrp exception-port) or as GSRP VLAN group-only control(gsrp limit-control).



Set up IP routing and enable failure monitoring.
Configure IP routing so that both GSRP switches can communicate with the upstream network. Set up the
dynamic monitoring functionality of dynamic routing or static routing so as to detect any failure in the
upstream network.

Continue communications through the direct link in case of failure in the upstream network.
In general, each GSRP switch is set to communicate with the upstream network. In case of failure in the
upstream network, the neighboring GSRP switch will be used to continue communication.

(3) port-up-delay is recommended if using OSPF.
Using OSPF to establish an upstream network causes a disconnection of one minute or so to occur whenrecovering the failure of any GSRP switch. Switchover from backup to master immediately occurs due to thedefault setting of GSRP (switch restarting), resulting in disconnection until OSPF adjacency is established.
To avoid such a situation, it is recommended that the GSRP parameter port-up-delay be set to 60 seconds ormore if using OSPF. With this setting, after restarting GSRP switches, OSPF adjacency is established before
switchover, reducing the disconnection period.
Specifying infinity to port-up-delay suppresses automated switchover. Use this option if you want tosuppress automated switchover.

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44

GSRP Usage Guide (Edition 1)

4.3

Configuration example

An example of a logical configuration is illustrated below. This section shows an example of each device based on
the logical configuration.

Server 1

System administration terminal

Server 2

172.16.255.10
S1:
AX3630S

0/1
VLAN 50

0/2
VLAN 51

VLAN 5,20
0/1

VLAN 5,30
0/2

0/24
VLAN 5VLAN group 2masterVLAN group 1
masterVLAN 5,20

GSRP switch A
C1: AX6304S

1/1

1/1

1/24

VLAN 2,100-101

3/2 3/3
VLAN 2,102,200

0/1
0/2
VLAN 2,100-101

F1:AX2430S

VLAN 100
0/5-12

MSU (1 sys)
3/1 3/2

3/24
VLAN 2,100-101

VLAN 2,201-202

VLAN 101
0/13-24

Management purpose

VLAN 102
0/5-12Control

VLAN 2,102,200

3/24
VLAN 2,201-202F3:
AX2430S

VLAN 200
0/13-24

0/1
0/2
VLAN 2,201,202
VLAN 201
0/5-12VLAN 202
0/13-24VLAN group 2

Data communication
VLAN group 1

VLAN 2
-

3/3

0/1
0/2
VLAN 2,102,200

F2:AX2430S

VLAN group 1

No.

1/24

VLAN 2,10

MSU (1 sys)
3/1

GSRP switch B
C2: AX6304S

VLAN 5,30

Upstream IP NWVLAN group 2

VLAN 100-102

VLAN 200-202

VLAN 10, 20, 30, 50-51

VLAN 100：192.168.100.0/24

VLAN 200：192.168.200.0/24

VLAN 10：10.0.0.0/24

C2:172.16.255.2

VLAN 101：192.168.101.0/24

VLAN 201：192.168.201.0/24

VLAN 20：20.0.0.0/24

S1:172.16.255.3

VLAN 102：192.168.102.0/24

VLAN 202：192.168.202.0/24

VLAN 30：30.0.0.0/24

VLAN

VLAN 5IP

C1:172.16.255.1

VLAN 50：172.16.50.0/24
VLAN 51：172.16.51.0/24

Figure 4.3-1 An example of the logical configuration of a backbone network

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

45

GSRP Usage Guide (Edition 1)(1) Configuration of the core switch (GSRP switch A)
Configuration of C1 (AX6304S)
Suppression of the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled by default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,5,10,20,100-102,200-202

Configures the VLAN to be applied. (*1)

Configuration of the GSRP
(config)# gsrp 1(config-gsrp)# gsrp-vlan 2

Configures the GSRP group IDs.
Assigns 1 to 4 GSRP group IDs.
(Configuration point (1))
Configures the GSRP-managed VLANs.

Configuration on Layer 3 redundancy switching(config-gsrp)# layer3-redundancy

Sets up Layer 3 redundancy switching.
(Configuration point (1))
Layer 3 can only be used with GSRP group IDs of 1 to 4.

Configuration of the direct link(config)# interface range gigabitethernet 1/24, gigabitethernet
3/24(config-if-range)# channel-group 1 mode on

Configures the channel group to make the direct-link redundant.
Configures Port channel 1 as GSRP1's direct link.

(config)# interface port-channel 1(config-if)# gsrp 1 direct-link

Configuration of master/backup(config)# gsrp 1(config-gsrp)# vlan-group 1 vlan 100-102(config-gsrp)# vlan-group 2 vlan 200-202(config-gsrp)# vlan-group 1 priority 200(config-gsrp)# vlan-group 2 priority 100

Configures a VLAN group.
Joins VLAN 100-102 in VLAN group 1 and VLAN
200-202 in VLAN group 2.
Configures the priorities among VLAN groups.
Assigns a higher priority to VLAN group 1 than Switch C2.
Assigns a lower priority to VLAN group 2.
(Configuration point (1)) (*1)

Configuration of the GSRP parameters(config-gsrp)# advertise-interval 0.5(config-gsrp)# advertise-holdtime 3(config-gsrp)# no-neighbor-to-master direct-down(config-gsrp)# port-up-delay 60(config)# gsrp limit-control

Configures the GSRP Advertise frames' transmission interval
and retention time. (Configuration point (1))
Configures the direct link failure detection function. Lets
backup automatically shift to master when there is a failure in
the direct link.
Configures port-up-delay to 60 seconds when using OSPF
as routing protocol. (Configuration point (3))
Enables limiting GSRP control to VLAN-group VLANs inorder to exclude the direct link from GSRP control.
(Configuration point (2))

Configuration of the physical port interfaces(config)# interface range gigabitethernet 1/1, gigabitethernet
1/24, gigabitethernet 3/1-3, gigabitethernet 3/24
(config-if-range)# link debounce time 0(config)# interface gigabitethernet 3/1(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,100-101(config)# interface gigabitethernet 3/2(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,102,200(config)# interface gigabitethernet 3/3(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,201-202

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Sets as small a link-down detection time as possible.
(Configuration point (1))
Configures each port.
The connected access switches of port 3/1-3 is GSRP aware.
Sets Port 3/1 as the trunk port, set VLAN 2 for GSRP control,and sets VLAN 100-101 for data transfer.
Sets Port 3/2 as the trunk port, set VLAN 2 for GSRP control,and sets VLAN 102 and VLAN 200 for data transfer.
Sets Port 3/3 as the trunk port, set VLAN 2 for GSRP control,and sets VLAN 201 and VLAN 202 for data transfer.

Port channel 1 is a GSRP direct link.
Sets this port channel as the trunk port, and sets up VLAN 2 for46

GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)(config)# interface port-channel 1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 2,10(config)# interface gigabitethernet 1/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 5,20

GSRP control and VLAN 10 for data transfer.
Port 1/1 connects to the upstream IP network.
Sets this port as the trunk port, and sets up VLAN 20 for datatransfer and VLAN 5 for remote control. (*1)

Configuration of VLAN interfaces(config)# interface vlan 100(config-if) ip address 192.168.100.1 255.255.255.0(config)# interface vlan 101(config-if) ip address 192.168.101.1 255.255.255.0

Assigns an IP address to each VLAN interface.
(Configuration point (1))
Assigns an IP address to VLAN 100.
Assigns the same IP address to Switch C2.
Assigns an IP address to VLAN 102.
Assigns the same IP address to Switch C2.

(config)# interface vlan 102(config-if) ip address 192.168.102.1 255.255.255.0

Assigns an IP address to VLAN 102.
Assigns the same IP address to Switch C2.

(config)# interface vlan 200(config-if) ip address 192.168.200.1 255.255.255.0

Assigns an IP address to VLAN 200.
Assigns the same IP address to Switch C2.

(config)# interface vlan 201(config-if) ip address 192.168.201.1 255.255.255.0

Assigns an IP address to VLAN 201.
Assigns the same IP address to Switch C2.

(config)# interface vlan 202(config-if) ip address 192.168.202.1 255.255.255.0(config)# interface vlan 10(config-if) ip address 10.0.0.1 255.255.255.0(config)# interface vlan 20(config-if) ip address 20.0.0.1 255.255.255.0

Assigns an IP address to VLAN 202.
Assigns the same IP address to Switch C2.
Assigns an IP address to VLAN 10.
Assigns 10.0.0.2/24 to Switch C2. (*1)
Assigns an IP address to VLAN 20.
Switch C2 is configured as VLAN 30, and then configure
30.0.0.1/24. (*1)

IP routing configuration (Configuration point (2)) (*1)
When using dynamic routing (OSPF)(config)# router ospf 1(config-router)# router-id 1.1.1.1(config-router)# network 10.0.0.0 0.0.0.255 area 0(config-router)# network 20.0.0.0 0.0.0.255 area 0(config-router)# network 192.168.0.0 0.0.255.255 area 0

Sets up OSPF.
Sets up the router ID and OSPF control network.

When using static routing(config)# ip route 172.16.50.0 255.255.255.0 20.0.0.2 100(config)# ip route 172.16.50.0 255.255.255.0 10.0.0.2 200(config)# ip route 172.16.51.0 255.255.255.0 20.0.0.2(config)# ip route 192.168.100.0 255.255.255.0 10.0.0.2(config)# ip route 192.168.101.0 255.255.255.0 10.0.0.2(config)# ip route 192.168.102.0 255.255.255.0 10.0.0.2(config)# ip route 192.168.200.0 255.255.255.0 10.0.0.2(config)# ip route 192.168.201.0 255.255.255.0 10.0.0.2(config)# ip route 192.168.202.0 255.255.255.0 10.0.0.2

Assigns neighboring gateway 20.0.0.2 to the next hop of
static route 172.16.50.0/24. Assign neighboring gateway
10.0.0.2 to the next hop of alternative route.
Assigns neighboring gateway 20.0.0.2 to the next hop of thealternative route of static route 172.16.51.0/24.
Assigns neighboring gateway 10.0.0.2 to the next hop ofalternative route of static routes 192.168.100.0/24,
192.168.101.0/24 and 192.168.102.0/24.
Assigns neighboring gateway 10.0.0.2 to the next hop ofalternative route of static routes 192.168.200.0/24,
192.168.201.0/24 and 192.168.202.0/24.

Configuration on remote management of the devices

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47

GSRP Usage Guide (Edition 1)
Configuration of C1 (AX6304S)(config)# interface vlan 5(config-if)# ip address 172.16.255.1 255.255.255.0

Sets up the IP address for the VLAN for remote control. (*1)
Permits telnet log-in (up to three at a time)(config)# line vty 0 2* (*1) in the table indicates the points where there are differences between Switch C1 and Switch C2.

(2) Settings of the core switch (Switch C2: GSRP switch B)
The table shows only the difference from C1.
Configuration of C2 (AX6304S)
Configuration of VLANs(config)# vlan 2,5,10,30,100-102,200-202

Configures the VLAN to be used.

Configuration of the GSRP
Configuration of master/backup(config)# gsrp 1(config-gsrp)# vlan-group 1 vlan 100-102(config-gsrp)# vlan-group 2 vlan 200-202(config-gsrp)# vlan-group 1 priority 100(config-gsrp)# vlan-group 2 priority 200

Configures a VLAN group.
Joins VLAN 100-102 in VLAN group 1 and VLAN
200-202 in VLAN group 2.
Configures the priorities among VLAN groups.
Assigns higher priority to VLAN group 2 than Switch C2.
Assigns lower priority to VLAN group 1.

Configuration of the physical port interfaces(config)# interface gigabitethernet 1/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 5,30

Port 1/1 connects to the upstream IP network.
Sets up this port as the trunk port, and set up VLAN 30 for datatransfer and VLAN 5 for remote control.

Configuration of VLAN interfaces(config)# interface vlan 10(config-if) ip address 10.0.0.2 255.255.255.0(config)# interface vlan 30(config-if) ip address 30.0.0.1 255.255.255.0

Assigns an IP address to each VLAN interface.
Assigns an IP address to VLAN 10.
Assigns an IP address to VLAN 30.

Configuration of IP routing
When using dynamic routing (OSPF)(config)# router ospf 1(config-router)# router-id 1.1.1.2(config-router)# network 10.0.0.0 0.0.0.255 area 0(config-router)# network 30.0.0.0 0.0.0.255 area 0(config-router)# network 192.168.0.0 0.0.255.255 area 0

Sets up OSPF.
Sets up the router ID and OSPF control network.

When using static routing(config)# ip route 172.16.51.0 255.255.255.0 30.0.0.2 100(config)# ip route 172.16.51.0 255.255.255.0 10.0.0.1 200(config)# ip route 172.16.50.0 255.255.255.0 30.0.0.2(config)# ip route 192.168.100.0 255.255.255.0 10.0.0.1(config)# ip route 192.168.101.0 255.255.255.0 10.0.0.1(config)# ip route 192.168.102.0 255.255.255.0 10.0.0.1(config)# ip route 192.168.200.0 255.255.255.0 10.0.0.1(config)# ip route 192.168.201.0 255.255.255.0 10.0.0.1(config)# ip route 192.168.202.0 255.255.255.0 10.0.0.1

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Assigns neighboring gateway 30.0.0.2 to the next hop of
static route 172.16.51.0/24. Assigns neighboring gateway
10.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 30.0.0.2 to the next hop of thealternative route of static route 172.16.50.0/24.
Assigns neighboring gateway 10.0.0.1 to the next hop ofalternative route of static routes 192.168.100.0/24,
192.168.101.0/24 and 192.168.102.0/24.
Assigns neighboring gateway 10.0.0.1 to the next hop ofalternative route of static routes 192.168.200.0/24,
192.168.201.0/24 and 192.168.202.0/24.

48

GSRP Usage Guide (Edition 1)
Configuration of C2 (AX6304S)
Configuration on remote management of the devices(config)# interface vlan 5(config-if)# ip address 172.16.255.2 255.255.255.0

Sets up the IP address for the VLAN for remote control.
Permits telnet log-in (up to three at a time)(config)# line vty 0 2(3) Configuration of server-handling switches
Configuration of S1 (AX3630S)
Suppression of the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled as default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 5,20,30,50-51

Configures the VLAN to be applied.

Configuration of the physical port interfaces(config)# interface range gigabitethernet 0/1-2(config-if-range)# link debounce time 0(config)# interface gigabitethernet 0/1(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 5,20

Sets as small a link-down detection time as possible.
(Configuration point (1))

Port 0/1 connects to Switch C1.
Sets up this port as the access port, and sets up VLAN 20 for
data transfer and VLAN 5 for remote control.

(config)# interface gigabitethernet 0/2(config-if)# switchport mode trunk(config-if)# switchport trunk allowed vlan 5,30

Port 0/2 connects to Switch C2.
Sets up this port as the access port, and sets up VLAN 30 for
data transfer and VLAN 5 for remote control.

(config)# interface gigabitethernet 0/5(config-if)# switchport mode access(config-if)# switchport access vlan 50

Port 0/5 connects to server A.
Sets up this port as the access port, and sets up VLAN 50 for
data transfer.

(config)# interface gigabitethernet 0/6(config-if)# switchport mode access(config-if)# switchport access vlan 51(config)# interface gigabitethernet 0/24
(config-if)# switchport mode access(config-if)# switchport access vlan 5

Port 0/6 connects to server B.
Sets up this port as the access port, and sets up VLAN 51 fordata transfer.
Port 0/24 is a system control port.
Sets up this port as the access port, and sets up VLAN 5 forremote control.

Configuration of VLAN interfaces(config)# interface vlan 20(config-if) ip address 20.0.0.2 255.255.255.0

Assigns an IP address to each VLAN interface.
Assigns an IP address to VLAN 20.

(config)# interface vlan 30(config-if) ip address 30.0.0.2 255.255.255.0

Assigns an IP address to VLAN 30.

(config)# interface vlan 50(config-if) ip address 172.16.50.1 255.255.255.0

Assigns an IP address to VLAN 50.

(config)# interface vlan 51(config-if) ip address 172.16.51.1 255.255.255.0
Configuration of IP routing (Configuration point (2))

Assigns an IP address to VLAN 51.

When using dynamic routing (OSPF)(config)# router ospf 1(config-router)# router-id 1.1.1.3(config-router)# network 20.0.0.0 0.0.0.255 area 0(config-router)# network 30.0.0.0 0.0.0.255 area 0(config-router)# network 172.16.0.0 0.0.255.255 area 0

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Sets up OSPF.
Sets up the router ID and OSPF control network.

49

GSRP Usage Guide (Edition 1)
Configuration of S1 (AX3630S)
When using static routing(config)# ip route 192.168.100.0 255.255.255.0 20.0.0.1 100(config)# ip route 192.168.100.0 255.255.255.0 30.0.0.1 200(config)# ip route 192.168.101.0 255.255.255.0 20.0.0.1 100(config)# ip route 192.168.101.0 255.255.255.0 30.0.0.1 200(config)# ip route 192.168.102.0 255.255.255.0 20.0.0.1 100(config)# ip route 192.168.102.0 255.255.255.0 30.0.0.1 200(config)# ip route 192.168.200.0 255.255.255.0 30.0.0.1 100(config)# ip route 192.168.200.0 255.255.255.0 20.0.0.1 200(config)# ip route 192.168.201.0 255.255.255.0 30.0.0.1 100(config)# ip route 192.168.201.0 255.255.255.0 20.0.0.1 200(config)# ip route 192.168.202.0 255.255.255.0 30.0.0.1 100(config)# ip route 192.168.202.0 255.255.255.0 20.0.0.1 200

Assigns neighboring gateway 20.0.0.1 to the next hop of
static route 192.168.100.0/24. Assigns neighboring
gateway 30.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 20.0.0.1 to the next hop of
static route 192.168.101.0/24. Assigns neighboring
gateway 30.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 20.0.0.1 to the next hop of
static route 192.168.102.0/24. Assigns neighboring
gateway 30.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 30.0.0.1 to the next hop of
static route 192.168.200.0/24. Assigns neighboring
gateway 20.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 30.0.0.1 to the next hop of
static route 192.168.201.0/24. Assigns neighboring
gateway 20.0.0.1 to the next hop of alternative route.
Assigns neighboring gateway 30.0.0.1 to the next hop of
static route 192.168.202.0/24. Assigns neighboring
gateway 20.0.0.1 to the next hop of alternative route.

Configuration on remote management of the devices(config)# interface vlan 5(config-if)# ip address 172.16.255.3 255.255.255.0

Sets up the IP address for the VLAN for remote control.
Permits telnet log-in (up to three at a time)(config)# line vty 0 2(4) Configuration of the access switches
Configuration of F1 (AX2430S)
Suppression of the spanning tree
(config)# spanning-tree disable

Disables PVST+, which is enabled as default in the AX series.
(Configuration point (1))

Configuration of VLANs(config)# vlan 2,100-101

Configures the VLAN to be applied.

Configuration of the physical port interfaces(config)# interface range gigabitethernet 0/1-2(config-if-range)# link debounce time 0(config-if-range)# switchport mode trunk(config-if-range)# switchport trunk allowed vlan 2,100-101(config)# interface range gigabitethernet 0/5-12(config-if-range)# switchport mode access(config-if-range)# switchport access vlan 100(config)# interface range gigabitethernet 0/13-24(config-if-range)# switchport mode access(config-if-range)# switchport access vlan 101

Sets as small a link-down detection time as possible.
(Configuration point (1))
Ports 0/1-2 connect to C1 and C2, respectively.
Sets up the port as the trunk port, set up VLAN 2 for GSRP
control, and set VLAN 100 and VLAN 101 for data transfer.
Ports 0/5-12 connect to the terminal.
Sets up the port as the access port, and set up VLAN 100 for
data transfer.
Ports 0/13-24 connect to the terminal.
Sets up the port as the access port, and set up VLAN 101 fordata transfer.

Note: Switches F2 and F3 have the same setting as F1, except for the VLANs to be handled.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

50

GSRP Usage Guide (Edition 1)

5.

Operational Management

This chapter describes operational management, including the operation commands used for establishing a
GSRP-enabled network and how to isolate the causes of failures.

5.1

Operation commands

GSRP operation commands are to be shown below.
(1) Operational commands to check for the state of GSRP show gsrp [detail]
Displays a summary of the state of GSRP; using [detail] (optional) shows the detailed information.
An exemple of the result of the show gsrp [detail] command in a GSRP switch
C1# show gsrp detail
Date 2010/04/20 16:17:19 UTC
GSRP ID: 1
Local MAC Address: 0012.e2a0.f600
Neighbor MAC Address: 0012.e2a0.3600
Total VLAN Group Counts : 2
GSRP VLAN ID: 2
Direct Port: 1/24,3/24
Limit Control: On
GSRP Exception Port
: No Neighbor To Master: direct-down
Backup Lock: disable
Port Up Delay: 60
Last Flush Receive Time : Forced Shift Time: Layer 3 Redundancy: On
Virtual Link ID: -Advertise Hold Time
Advertise Hold Timer
Advertise Interval
Selection Pattern
VLAN Group ID
12... [GSRP configuration status]
Displays the detail of the GSRP of the switch

Local
: 3
: 3
: 0.5
: ports-priority-mac

Local State
MasterBackup

Neighbor
3
0.5
ports-priority-mac

Neighbor State
BackupMaster…[GSRP master/backup status]
Displays the GSRP Advertise timer
value and selection method of themaster/backup…[VLAN group status]
VLAN group 1 uses this (C1) as themaster.
VLAN group 2 uses the opposite (C2)
as the master.

 show gsrp aware
Displays the information on the GSRP aware switches; this command must be executed on any GSRP
aware switch.
An exemple of the result of the show gsrp aware command executed in a GSRP aware switch
F1# show gsrp aware
Date 2010/04/20 16:18:54 UTC
Last MAC Address Table Flush Time
GSRP Flush Request Parameters :GSRP ID : 1
VLAN Group ID : 1
Source MAC Address : 0012.e2a0.f600: 2010/04/20 16:10:52
Port : 0/1

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

…[GSRP aware status]
The last time it flushed the Mac
Address table…Information on the last GSRP that flushed the
Mac Address table(The port that received the GSRP ID/VLAN group
ID/flush frames)

51

GSRP Usage Guide (Edition 1)(2) Operation commands to control GSRP states set gsrp master
Shifts the backup (No neighbor) state to the master; this command is valid only for the backup (Noneighbor) state.
 clear gsrp port-up-delay
In a VLAN assigned to a VLAN group, this command promptly updates a port in the link-up state to an
active port, without waiting for the delay time configured with the port-up-delay configurationcommand.
(3) Operation command to reset abnormal GSRP states restart gsrp
Restart GSRP program after issuing the confirmation message for restart. All VLANs belonging to any
GSRP VLAN groups stop receiving any frames, resulting in the termination of the communication.

5.2

Example of GSRP failureThis section explains a case where a GSRP switch encounters a failure in a GSRP-enabled Layer 3 system. See
Figure 4.3-1 for detailed configuration.

(1) Normal operation status
GSRP group 1 has two VLAN groups; VLAN group 1 sees GSRP switch A as the master, while VLAN group 2sees GSRP switch B as the master. The upstream IP network is routed by OSPF. The GSRP states of both coreswitches are shown below.
Normal operation status of the GSRP switch
C1# show gsrp
Date 2010/04/23 10:29:19 UTC

C2# show gsrp
Date 2010/04/23 10:29:35 UTC

GSRP ID: 1
Local MAC Address: 0012.e2a0.f600
Neighbor MAC Address: 0012.e2a0.3600
Total VLAN Group Counts : 2
Layer 3 Redundancy: On

GSRP ID: 1
Local MAC Address: 0012.e2a0.3600
Neighbor MAC Address: 0012.e2a0.f600
Total VLAN Group Counts : 2
Layer 3 Redundancy: On

VLAN Group ID
1
2

VLAN Group ID
1
2

Local State
MasterBackupC1# show vlan list
Date 2010/04/23 10:30:18 UTC
VLAN counts:10
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 42 VLAN0001
2 Up
5/ 5/ 5 VLAN0002
10 Up
2/ 2/ 2 VLAN0010
20 Up
1/ 1/ 1 VLAN0020
100 Up1/ 1/ 1 VLAN0100
101 Up1/ 1/ 1 VLAN0101
102 Up1/ 1/ 1 VLAN0102
200 Down
0/ 1/ 1 VLAN0200
201 Down
0/ 1/ 1 VLAN0201
202 Down
0/ 1/ 1 VLAN0202

Neighbor State
BackupMaster

Type
Port
Port
Port
Port
Port
Port
Port
Port
Port
Port

Protocol
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:

1(M)
1(M)
1(M)
2(B)
2(B)
2(B)

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

Local State
BackupMaster

C2# show vlan list
Date 2010/04/23 10:30:28 UTC
VLAN counts:10
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 42 VLAN0001
2 Up
5/ 5/ 5 VLAN0002
10 Up
2/ 2/ 2 VLAN0010
20 Up
1/ 1/ 1 VLAN0020
100 Down
1/ 1/ 1 VLAN0100
101 Down
1/ 1/ 1 VLAN0101
102 Down
1/ 1/ 1 VLAN0102
200 Up0/ 1/ 1 VLAN0200
201 Up0/ 1/ 1 VLAN0201
202 Up0/ 1/ 1 VLAN0202

Neighbor State
MasterBackup

Type
Port
Port
Port
Port
Port
Port
Port
Port
Port
Port

Protocol
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)

52

1(B)
1(B)
1(B)
2(M)
2(M)
2(M)

GSRP Usage Guide (Edition 1)(2) Operations in case of GSRP failure
If GSRP switch A, a core switch, encounters a device failure, the switchover of GSRP master and backup occurs. In
this case, GSRP switch A (Switch C1), where VLAN group 1 acts as the master, encounters a device down, and theneighboring GSRP switch B (Switch C2) detects GSRP Advertise timeout, which invokes the switchover of GSRP.
The messages issued from each switch in case of failure in GSRP switch A are shown below.
Messages from devices in case of MSU module failure+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Switch C1, core switch (GSRP switch A)+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:29 E8 MSU 25070202 2301:400100001000 MSU restarted because of PSP hardware failure.
… PSP hardware failure caused MSU module to restart
04/23 10:49:30 E3 VLAN 20130013 0700:000000000000 GSRP 1 VLAN group 1 : advertise timeout detected on Master.
04/23 10:49:30 E4 VLAN 20130011 0700:000000000000 GSRP 1 VLAN group 2 : state transitioned to Backup(No Neighbor).
04/23 10:49:31 E3 MSU 01200171 2301:455f00000001 This system (MSU1) restarted due to its failure.
… GSRP Advertise timeout was detected, resulting in No neighbor. Then the switch restarted due to MSU module failure.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Switch C2, core switch (GSRP switch B)+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:32 E4 PORT GigabitEthernet1/24 25011101 1350:a00000004120 Error detected on the port.
04/23 10:49:32 E3 MAC 20120010 0800:000000000000 Port(1/24) detached from Channel Group(1) - Port down.
04/23 10:49:32 E4 PORT GigabitEthernet3/24 25011101 1350:a00000004120 Error detected on the port.
04/23 10:49:32 E4 VLAN 25100002 0700:000a00000000 VLAN (10) Status is Down.
04/23 10:49:32 E3 MAC 20120010 0800:000000000000 Port(3/24) detached from Channel Group(1) - Port down.
04/23 10:49:32 E4 MAC 20120003 0800:000000000000 Channel Group(1) is Down - All port detached.
… As neighboring switch (C1) went down, port channel 1 enters link-down.
04/23 10:49:33 E4 VLAN 20130007 0700:000000000000 GSRP 1 VLAN group 1 : state transitioned to Master, because the direct link
failure was detected.
04/23 10:49:33 E3 VLAN 20130013 0700:000000000000 GSRP 1 VLAN group 2 : advertise timeout detected on Master.
… As GSRP direct link entered link-down, VLAN group 1 shifted to master.
04/23 10:49:33 E4 VLAN 25100001 0700:006400000000 VLAN (100) Status is Up.
04/23 10:49:33 E4 VLAN 25100001 0700:006500000000 VLAN (101) Status is Up.
04/23 10:49:33 E4 VLAN 25100001 0700:006600000000 VLAN (102) Status is Up.
04/23 10:49:34 E3 VLAN 20130013 0700:000000000000 GSRP 1 VLAN group 1 : advertise timeout detected on Master.
… As VLAN group 1 (VLAN100,VLAN101,VLAN102) shifted to master, the VLAN went up.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Server Switch S1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:33 E4 PORT GigabitEthernet0/1 25011101 1350:70020000e125 Error detected on the port.
04/23 10:49:33 E4 VLAN 25100002 0700:000100000000 VLAN (20) Status is Down.
… Down in neighboring switch (C1) caused Port 0/1 to go link-down, resulting in down of VLAN20.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Access Switch F1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:35 E4 PORT GigabitEthernet0/1 25011101 1350:70020000e125 Error detected on the port.
04/23 10:49:36 E3 VLAN 20130015 0700:000000000000 GSRP aware : MAC Address Table entry cleared,because GSRP flush request received
on port 0/2, GSRP 1 VLAN group 1 Source MAC address 0012.e2a0.3600.
… GSRP Flush request frames of VLAN group 1 was received from GSRP switch B (C2), MAC address table was cleared.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Access Switch F2+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:31 E4 PORT GigabitEthernet0/1 25011101 1350:70020000e125 Error detected on the port.
04/23 10:49:32 E3 VLAN 20130015 0700:000000000000 GSRP aware : MAC Address Table entry cleared,because GSRP flush request received
on port 0/2, GSRP 1 VLAN group 1 Source MAC address 0012.e2a0.3600.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Message from Access Switch F3+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
04/23 10:49:31 E4 PORT GigabitEthernet0/1 25011101 1350:70020000e125 Error detected on the port.
… GSRP Flush request frames of VLAN group 1 was received from GSRP switch B (C2), MAC address table was cleared.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

53

GSRP Usage Guide (Edition 1)
As GSRP switch A encounters a failure into a down state, VLAN group 1 in GSRP switch B shifts from backup tomaster. VLAN group 2 keeps its state of master, resulting in two VLAN groups in a master state.
The operational status of GSRP switch B is shown below.
Operational status of GSRP switch B after a failure
C2# show gsrp
Date 2010/04/23 10:51:35 UTC
GSRP ID: 1
Local MAC Address: 0012.e2a0.3600
Neighbor MAC Address: Total VLAN Group Counts : 2
Layer 3 Redundancy: On
VLAN Group ID
1
2

Local State
MasterMaster

C2# show vlan list
Date 2010/04/23 10:51:48 UTC
VLAN counts:10
ID
Status Fwd/Up /Cfg Name
1 Down0/ 0/ 42 VLAN0001
2 Up
5/ 5/ 5 VLAN0002
10 Up
2/ 2/ 2 VLAN0010
20 Up
1/ 1/ 1 VLAN0020
100 Up1/ 1/ 1 VLAN0100
101 Up1/ 1/ 1 VLAN0101
102 Up1/ 1/ 1 VLAN0102
200 Up1/ 1/ 1 VLAN0200
201 Up1/ 1/ 1 VLAN0201
202 Up1/ 1/ 1 VLAN0202

In both VLAN groups 1 and 2,
GSRP switch B acts as themaster.

Neighbor State
-

Type
Port
Port
Port
Port
Port
Port
Port
Port
Port
Port

Protocol
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:
GSRP
1:

1(M)
1(M)
1(M)
2(M)
2(M)
2(M)

GSRP GSRP ID:VLAN Group ID(M:Master/B:Backup)(3) Operation after the recovery of GSRP failure
In GSRP, as the port-up state obtained by a failed switch or port will be immediately reflected into an active port, aswitchover (shift from backup to master) with priority will be automatically executed.
In an upstream network utilizing OSPF, however, the automated switchover of GSRP recovery might take a longtime to restart the stopped communication.
To avoid such a situation, automated switchover can be suppressed by using the GSRP configuration command
port-up-delay infinity. Use operation command clear gsrp port-up-delay to shift the states ofmaster/backup.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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GSRP Usage Guide (Edition 1)

6.

Precautions(1) Compatibility with other functionalities
The following functions have a problem regarding coexistence with GSRP.
 No spanning tree function (single spanning tree, PVST+, multiple spanning trees) is compatible with GSRP
in one device.
 VRRP and GSRP cannot be used in the same switch at the same time.
(2) Using port resetting in a load-balanced configuration
When you configure port resetting to one physical port that is shared with multiple VLAN groups, a shift of one ofsuch VLAN groups from master to backup causes a communication interrupt, since the port is temporarily in alink-down state, although no other VLAN groups shift from master.
If you want to avoid such temporal link-down while using port resetting, make sure that multiple VLAN groups do
not share one physical port.
(3) Applying GSRP to a newly built network
Take the following measures to avoid frame loop when configuring GSRP into a network.


Shutdown ports during configuration
Prior to configuring GSRP, set the ports to the opposite switch to shutdown to set it in a down state. Afterthe configuration, wait for the stable-state configuration of GSRP before starting operation.
Start and set up GSRP switches one by one
Of the two GSRP switches constituting a GSRP group, start and configure one switch, and make sure it has
shifted to backup before starting and configuring the other GSRP switch.

(4) In case of high CPU load
A heavy load placed on a CPU might cause the discarding of some of the received GSRP Advertise frames or mightcause processing delays, leading to the output of timeout messages or state shifts. If such a state takes placefrequently, set up a larger value to the transmission interval and retention time of the GSRP Advertise frames.

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

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GSRP Usage Guide (Edition 1)

Appendix: Configuration Files
This appendix shows the configuration examples described in this guide. All the configurations for the switches ofLayer 2 systems in Part 2 and Layer 3 systems in Part 3 are attached to this file as a text file. (Extracting the attachedfiles requires Adobe Reader 6.0 or later.) For each configuration, refer to the attached file that matches with thefilename.
(1) Part 2 Layer 2 system
Application example of GSRP in Layer 2
Load-distributed configuration

Switch
C1：AX6304S
C2：AX6304S
F1：AX2430S

Filename
L2_C1-AX63S.txt
L2_C2-AX63S.txt
L2_F1-AX24S.txt

Switch
C1：AX6304S
C2：AX6304S
F1：AX2430S
F2：AX2430S
F3：AX2430S

Filename
1_L3_C1-AX63S.txt
1_L3_C2-AX63S.txt
1_L3_F1-AX24S.txt
1_L3_F2-AX24S.txt
1_L3_F3-AX24S.txt

Switch
C1：AX6304S
C2：AX6304S
F1：AX2430S
F2：AX2430S
F3：AX2430S

Filename
2_L3_C1-AX63S.txt
2_L3_C2-AX63S.txt
2_L3_F1-AX24S.txt
2_L3_F2-AX24S.txt
2_L3_F3-AX24S.txt

Switch
C1：AX6304S

Filename
3_L3_C1-AX63S_ospf.txt
3_L3_C1-AX63S_static.txt
3_L3_C2-AX63S_ospf.txt
3_L3_C2-AX63S_static.txt
3_L3_S1-AX36S_ospf.txt
3_L3_S1-AX36S_static.txt
3_L3_F1-AX24S.txt
3_L3_F2-AX24S.txt
3_L3_F3-AX24S.txt(2) Part 3 Layer 3 system
Application example 1 of GSRP in Layer 3
Configuration of a basic system

Application example 2 of GSRP in Layer 3
Configuration of a network separation system

Application example 3 of GSRP in Layer 3
Configuration of a backbone network

C2：AX6304S
S1：AX3630S
F1：AX2430S
F2：AX2430S
F3：AX2430S

Copyright © 2010, ALAXALA Networks Corporation. All rights reserved.

57

Edition 1 issued on May 28, 2010

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