Control Protocol
andOAM in MPLS-TP Network
UTStarcom Inc.
Broadband Business Unit
System Architect, Senior Manager
Dr. Wang Yong

MPLS Japan 2008

1Agenda
1. MPLS-TP Based Metro Network
2. Functions of Control Protocol and OAM
3. Relationship of Control Protocol and OAM
4. Conclusion

MPLS Japan 2008

MPLS-TP Based Metro Network• Evolution of current MSPP network– VC,VCG, LCAS cannot solve the data bursting problem
effectively in future All-IP services

MPLS Japan 2008

Why MPLS-TP?
• MPLS-TP network concentrates on– Effectively transmission of bursting data
– Uniform transmission platform for every kind of current network– MPLS-TP network element Inherits both the packet andtelecommunication characteristics:• Label switching, QoS, Control Plane• OAM, less than 50ms protection, synchronization and high reliability

MPLS Japan 2008

MPLS-TP NE Benefits• Based on label switching• Support QoS-guaranteed Multi-Service by PWE3 andsophisticated QoS mechanism• Layered rich OAM tools for operation and fault
management• Support high accuracy timing and clock• High Reliability, equipment protection, network
protection less than 50ms
• Low cost for dollars per kbps, dollars per port

MPLS Japan 2008

MPLS-TP Equipment Layering Model

Applications

FE/GE/10GE

Ethernet OAM, ATM
OAM, TDM OAM

ATM STM-1

Ethernet

ATM

E1/T1/STM-1

TDM

Pseudo-wire
PW OAM, LSP OAM

Client Service
Layer
Server Layer

TunnelEthernet OAM, SDH OAM,OTN OAM

Ethernet

SDH/SONETWDM/OTNMPLS Japan 2008

Link Layer

Multi-Service Support

UplinkLayer

PacketSwitchPseudoWire

Client Layer

ClientEquipment

FE/GE/10GE

OpticalLink
155M/1G/2.5G/10G

PW1

LSP1..
PWn

LSP2
LSP31000M
50M
30M

L2/3switch

Ethernetover MPLSCircuitEmulation
ATM overMPLS

E1/T1/STM-N

SDH/PDHATM STM-1

ATM

MPLS Japan 2008

Functions of Control Plane and OAM• MPLS-TP needs considering both Control Planeand OAM• Control Plane means– Routing, Signaling protocols, mainly used in existing IP/MPLS
network• OAM means– Fault management, ex: APS; performance management,
ex: B1/B2/B3, mainly used in telecommunication

MPLS Japan 2008

MPLS-TP NE ArchitectureManagement PlaneEMS/NMS

SNMP, CLIPW OAM, LSP OAMTDM OAM, Ethernet
OAM, ATM OAM…

OSPF-TENHLFE, Label Stacking

OAM

RSVP-TE/LDPControl Plane

Label
Switching

Data Plane

MPLS Japan 2008

PHP,ECMP

What CP Does?

SCN
GW

SCN-A
SCN-A

SCN-B
SCN-B

Provider A
ACCP

I-NNICP

I-NNI

T-PE
C1A

B

Provider B
CP

S-PE

C

DLSPPW-Seg.
AB
TunnelPW-Segment A

RSVP-TET-LDP
RSVP-TECP

S-PE

LSP-Tunnel A

T-LDP

E-NNI

RSVP-TEAC – Attachment Circuit
NNI – Network-Network Interface
I-NNI – Internal NNI
E-NNI – External NNI
SCN – Signaling Communication
Network
SCN-GW Gateway
T-LDP – Targeted LDP
MPLS Japan 2008

I-NNICPCPE

F

LSP-Tunnel B
PW-Segment B

RSVP-TE

AC

T-PE

T-LDP
RSVP-TE

I-NNI

T-LDP
RSVP-TE

RSVP-TE

C2

What OAM Does?
Attachment circuit
Attachment circuit

Carrier 1

Carrier 2

UNI
CEPEPP

UNI

NNI

PE-S

P

PE-SPE

end to end PW OAM (with PW switching)
MEP

MIP

MIP

MEP

end to end LSP OAM
MEP

MIP
segment
LSP OAM(inter carrier)segment LSP OAM(carrier 1)
MEP

MIP

MIP

MIP

MEP MEP• PW and LSP OAM Monitoring
MPLS Japan 2008

MEP MEP

MEP
segment LSP OAM(carrier 2)
MIP

MEPCE

PW OAM Mapping
Alarm

PE1

PE2

CSF, AISAC Forward
Defect 1

PW Reverse

Defect 2…

CE1
PW Forward
AC Reverse•

AC defect can be notified to PW and vice versa, this is called PW
OAM Mapping– Currently trying to extend it to OAM mapping between PW•••

AC LOS can be reported to remote site as CSF
LSP LOC can be reported to remote site as AIS
Signaling protocol can also convey the above information
MPLS Japan 2008

CE2

Relationship of Control Protocol and OAM• MPLS-TP requirements– Configuration of LSP and PW are not solely on CP• Static provisioning is desired• With Static provisioning, no dependency on routing orsignaling– If there is CP, CP failure and recovery must not impact thedata plane– Independent Transport OAM for LSP and PW, with full
FCAPS capabilities• CV/CC, AIS,RDI, LB, LM, DM, APS, MCC, SCC, CSF,LCK, TST, EXP, VSM…
– Consistent OAM capabilities for multi-layered network andinter-working of the different layers/technologies• OAM and CP are competing sometimes• OAM and CP are placatory

MPLS Japan 2008

Sometime OAM is Better• In some cases, OAM and CP are competing,both can be used
– AC status notification: LDP vs PW OAM mapping– Protection/restoration:• Linear: RSVP Protection Switching vs. OAM Linear 1:1• Ring: RSVP FRR vs TM-SPRING• The difference is:– OAM is hardware based, fast and reliable, CP is not so fastand reliable

Common Knowledge!
MPLS Japan 2008

Sometimes CP is Better• In some cases, CP has advantage, but OAM is also
progressing– Multi-segment PW redundancy
Active MS-PW
Router

TNATM-SWTN

IP/MPLSBSRouter

T-PE
RouterTN

Standby MS-PW

MPLS Japan 2008

RNC

Dynamic PW Method 1S-PE
Router

S-PE

SS-PW 5SS-PW1

ATM-SW

T-PE

SS-PW 2

SS-PW 4

BS

IP/MPLS

T-PE
Router

RNC
S-PE

S-PE
Router

SS-PW 3MS-PW

•Method 1: Using PW AII routing table to find the next PE,
so CP can dynamic selecting S-PE, to stitching multiple SS-PW
into one MS-PW

MPLS Japan 2008

Dynamic PW Method 2
S-PE

ATM-SW

Active PW

S-PE
Router

T-PE

IP/MPLS

BS

T-PE
RouterRNC
S-PE
RouterS-PE

Standby PW

Standby PW••Method 2: PW redundancy relies on extensions to PW signalingthat use LDP status messages to indicate the active or standby
state of a PW and let the T-PE synchronize the PW used.
OAM can do protection on this special topology similarly as
DNI, currently in exploring

MPLS Japan 2008

Co-work of OAM and CP

Control
Plane
Edge

OAM

OAM

Forwarding
TablesControl
Plane

Edge

Control Channel

In most cases, OAM and CP are placatory
CP is responsible for:––––•OAM

Forwarding
TablesForwarding
TablesControl Channel••

ControlPlane

End to End, Segment LSPs and PWE-3 setup/teardown/modification
Determining and defining primary and backup paths
Configuring the OAM function along the path
Note: ALL these can be done by Management plane

OAM is responsible for:– Monitoring and driving switches between primary and backup
paths for the end to end path and path segments
MPLS Japan 2008

Conclusion• MPLS-TP network is uniform transmission network• OAM is key component of MPLS-TP• Control plane works better when inter-working withlegacy IP/MPLS network and dynamic PW placement
is needed

MPLS Japan 2008

Thank You

MPLS Japan 2008