Nokia SR OSにおけるSR/SRv6
実装状況と今後の展望
NOKIA
鹿志村康生
yasuo.kashimura@nokia.com
1© 2021 Nokia

次世代のTransportネットワークの要求事項
ハイスケールでの Traffic
Engineering

IPv6 サポート

5Gユースケースのサポート• インフラ全体でのIPv6のサポート• eMBB, URLLC, mMTC サービスユースケースのサポート

コアネットワークでのState削減

テクノロジの確実さ

エンタープライズサービス• エッジのみでPathのStateを管理• 複数の導入実績によってテクノロジの確かさが証明されていること• P2P, P2MP L2/L3 VPN サービス

• オンデマンドなクラウドサービスのための粒度の細かいTraffic
Engineering• 投資保護につながるテクノロジ

2

SDNベースのコントロール

技術標準の成熟度

クラウドユースケース• ネットワークワイドでのViewを持つ
SDNコントローラーでのPath
Computeとコントロール• IETF等Standard Communityにおいて相互接続のための技術標準が固まっていること• ダイナミックなマルチクラウド間の接続性のサポート

プロトコルのシンプル化

サービスチェイニング

• 使用するネットワークプロトコルの種類の削減• 細かい粒度でのDC内のサービスへの柔軟な接続© 2021 Nokia

Nokia SR OSでのSegment Routing サポートの歴史

標準化の取り組みと共にSR OSへの実装、多くのユーザーでの導入
2015

2016

2017

2018

2019

2020

2021

SDN for carrier networks
SR OS

NSP

Segment Routing!"#$%&'
Node () Controller *+,Shortest pathwith protection
SR-ISIS/SR-OSPF
LFA/R-LFA

Traffic engineering
PCC-init SR-TE
PCC/PCE topology
discovery

Legacy MPLS-.%/012+345%67%89:;
12+<#$=OAM, Control, Protection

OAM and operations

Enhanced control

LSP Ping/Trace
SR-TE Auto-LSP

PCE-init SR-TE
Static and BGP SRpolicy
LSP admin-tagging

E2E
robustness/visibility

IPv6>%Seamless Transition

Primary/Standby SR-TE
Seamless BFD for SR-TEand SR policy
Enhanced statistics

IPv6 control plane
IPv6 SR w/MPLS dataplane

IPv6 control + Data
plane
SRv6

Interop-testing Orange Labs/EANTC 2016-2020
SR-ISIS/SR-OSPF
tunnels
LSP-Ping/LSP-Trace
LFA/Remote LFA/TILFA
3© 2021 Nokia

PCEP and BGP-LS
Cisco/Juniper/Huawei

BGP SR-Policy
Cisco/Arista/Huawei

BGP Prefix SID
Cisco/Arista

SR-MPLS/SRv6 various
tests with multiplevendors

Nokia SR OSでのEVPN サポートの歴史

標準化の取り組みと共にSR OSへの実装、多くのユーザーでの導入
2014

2015

2016

2017

2018

2019

2020

2021

EVPN
SROS
Cloud!"DC#$%&'()*+)EVPN,-.$/0DC#$%&'(EVPN-VXLAN
L2 and IRB
VXLAN to VPLS GW
Assisted Replication
VXLANv6
Host Routing
EVPN-VPWS VXLAN
VXLAN instances
IRB Asymmetric
IRB Interface-ful

4© 2021 Nokia

EVPN
SRLinux

WAN Network12)EVPN
MEF/$34
EVPN-MPLS
Multi-Homing
PBB-EVPN
Proxy-ARP/ND
EVPN/VPLS iw
EVPN/VPWS iw
IGMP-snooping
EVPN-E-TreePBB E-Tree

Cloud-WAN(5678$9:5;Network Function Interconnect (NF-IX)<4=$0;SR/SR-Policy)>?@(5678$9:5
EVPN VXLAN / MPLS
I-ES Multi-Homing
Security
Loop Protection
EVPN-VPWS
Virtual ES
EVPN for NF-IX
Asymmetric model B
MPLS instances

EVPN – AB)/$34)CDL2 Services
EVPN-VPWS LLF
EVPN Oper-Groups
ALMP Permit-List
VPWS local switching

L3 Services
IFL Model
IFL and IPVPN iw

L2/L3 Multicast
EVPN mLDPOISM for IR
OISM for mLDP
EVPN IGMP/MLD Proxy
EVPN Mcast Synch
OISM-MVPN/PIM iw

SRv6 Services
EVPN VPWS SRv6
SRv6 PW-HeadEnd

Protection/OAM

SR-TE : マルチドメイントランスポート

Programmaticcontrol

マルチドメインでのEnd-to-EndでのサービスプロテクションTraffic engineering

PCEP or NetConf

NSP

Controlplane

Controlller

BGP-LS

node-sid =13005
SR-TE LSP
Primary ERO =13005,13006,13007,13008,13009
Standby ERO =13013,13012,13011,13010,13009

node-sid =13008

Primary pathwith S-BFD

node-sid =13006
R4

R9
R5

R7

R2

R6

R8

node-sid =13013

node-sid =13012

node-sid =13011

R1

node-sid =13009

node-sid =13007

R11

Standby path with S-BFD• Seamless BFDによるLSPデータパス障害のFast Detection• 1つのSR-TE LSPにおいてPrimary/Standyパス• ActiveパスのS-BFDのDownによりFailoverがトリガされる• 全てのS-BDFセッションがDownした場合は次のLSPにFallback5© 2021 Nokia

R10node-sid =13010

R12

Programmaticcontrol

SR-TE : マルチドメインでのEgress Peer Engineering

Traffic engineering

SR-TE/BGP-LSを使用したTEプログラマビリティー

BGP IPv4
prefix: 1.1.1.0/24
color: 29543631

PCEP or BGP
SR Policy

NSP

BGP SR-policy
color: 29543631
endpoint: 0.0.0.0
segment-list: 13005, 29387, 130609

PCEP PCInitiate
PATH-SETUP-TYPE: Segment Routing
Endpoint object: dest-ip 192.0.2.11
SR-ERO object: 13005, 29387, 130609

R4ControlplaneController

BGP SR-policy
binding-sid: 130609
segment-list: 14007,14009
BGP-LS
BGP peer = R6, peer-node-sid: 29387
BGP peer = R8, peer-node-sid: 29388
IGP node-sidlabel=14009

IGP node-sid
label=13005

192.0.2.11

R1R2eBGP
R3

R5Peer Node SID
pop: 29387
next-hop: if_to_R6

6© 2021 Nokia

R6

R8

R7

IGP node-sid label=14007

R9R11

Programmaticcontrol

SR-TE : Color-awareでのAuto-LSP

Traffic engineering

SR-TE と PCEP によるシンプルなプロビジョニング
PCEP

SR-TE Auto LSP
ERO=13005,13006,13007,13008,13009

NSPController

BGP-LS

node-sid =13005

node-sid =13008

R4

Route Import Policy:
from:family vpn-v4
next-hop 10.10.0.10
community red
action accept
admin-tag-policy red-lsps
create-mpls-tunnel

node-sid =13006

node-sid =13007
R9R1R2R3R5R7VRF
R11R10R6

node-sid =13012

R8

node-sid =13011

BGP Route:
Next-hop
10.10.0.10
Community: Red© 2021 Nokia

node-sid=13009

10.10.0.10
node-sid =13013

7

Control planenode-sid =13010

R12

SR OS 21.0でのSRv6実装
Data/Controlプレーン• SRv6 ISIS shortest-path tunnel support• SID function support:– End (node SID)
– End.X (adjacency SID)
– End.DT4 (IPv4 VRF, IPv4 Base), End.DT6 (IPv6 VRF, IPv6Base), END.DT46 (IPv4/IPv6 VRF, IPv4/IPv6 Base)– End.DX2 (EVPN-VPWS)• LFA/remote LFA/TI-LFA with SRH insertion• PSP (Penultimate Segment Popping) of SRH• USP (Ultimate Segment Popping) of SRH• Inserting hash output into flow label field at ingress PErouter• Hashing based on flow label at transit P router• Flexible algorithm: admin-group include/exclude,IGP/TE/Latency metric• Flexible algorithm aware locator summarization• Uniform ECMP Failover for locator prefix8© 2021 Nokia

サービス• IP-VPN (family vpn-ipv4 and vpn-ipv6).
• BGP IPv4 and IPv6 routes in base routing instance• EVPN-VPWS with multi-homing support (family evpn)

OAM• Ping/Traceroute for IPv4/IPv6 VRF routes• Ping/Traceroute for IPv4/IPv6 base router routes• Ping/Traceroute of a SID/locator• TWAMP Light for dynamic interface latency
measurement (base and flex-algo topologies)• Eth-CFM in EVPN-VPWS service

プラットフォーム
• 7750 SR / 7950 XRS FP4 プラットフォーム

SRv6 data/control プレーン

Transposition

ISIS/OSPFでのAdvertise:RD2• Locator• END SID (Node SID) 及び END.X SID (adjacency SID)

ESI
Eth-Tag ID=2

BGPでのAdvertise:• Service SID: END.DT46 (VPRN), END.DX2 (EVPN)Block (40b)Node (24b)

FUNCT (20b)Sub-SubTLV=1

PE6

PE1

ISIS locator
2001:1:0:6::/64
IP DA=(2001:1:0:6):(abcd:e)::
IP Fields / Next-Hdr= EthEthernet Payload© 2021 Nokia

SID = (2001:0001:0000:0006):(abcd:e)000:0000:0000

Loc Node=24

IP SA= 2001:1:0:1::1

9

ARG (0)

EVPN-VPWS
AD per-EVI route
END.DX2 SID
2001:1:0:6:abcd:e::/84

LocatorPE1 configuration
Locator prefix
2001:1:0:1::/64
SRv6 source-address(loopback):
2001:1:0:1::1/128
End.DX2:
2001:1:0:1:b1:b100::/88

Label =0xabcde0

PE6 configuration
Locator prefix
2001:1:0:6::/64
SRv6 source-address (loopback)
2001:1:0:6::1/128
End.DX2 SID function (allocated orconfigured):
2001:1:0:6:abcd:e::/84

Trans
Offset=64

Note:

Len=6
FUNC
Len=20

Loc Len=40
ARG Len=0Trans Len=20

SRV6 Service TLV - Encodedin BGP Prefix SID Attribute• DefaultでNLRI Label fieldの上位20bitをFunctionfieldに使用する

SRv6 PWヘッドエンドアーキテクチャ

CE3EVPN-VPWS SRv6ユースケース

PE3IP-VPN

BackhaulアクセスでのEVPN-VPWS SRv6によるアクセス〜L2/L3VPN PE間の接続• PWヘッドエンドPEがEVPN-VPWSを終端し上位側のサービスにStitchする• CustomerごとにVLAN内のQoS, OAM及びSecurityが提供される

SRv6 or MPLS
L2/L3 VPNEVPN or IP-VPN

PE1
Headend
End.DX2 A1::10
DF

AD pe-EVI
P=1

IP-VPN

IP-VPNVPWS10VPWS10Virtual Ethernet segment
Single-Active

ADpe-EVI
B=1

Ethernet outer
IPv6 DA = A1::10
SA = B1::1
Next-header = Eth

冗長性:• SRv6ネットワーク内でのSRv6 TI-LFA• EVPN Single-Active Multi-HomingによるPE冗長• vES(virtual Ethernet Segment)により4つまでのPEへ
Multihome, DF Electionにより1つのActiveと3つのBackup

10© 2021 Nokia

PE2 headend
Non-DF

SRv6
EVPN-VPWS
backhaul

Ethernet payload

Ethernet outer
IPv6 DA = A2::10
SA = A1::1
Next-header = EthEthernet payload

VPWS10VPWS20VPWS30RadioCE1

CE2

SR-MPLSとSRv6のInterwork*[ex:configure service vprn "IP-VRF-SRv6-1"]
A:admin@PE1# info

IP-VPNのService Interwork Gateway
VPN-IPv4 Route

VPN-IPv4 Route

20.0.0.1/32
Label = 524255
NH = cafe:1::4
SRv6 SID: cafe:1:0:2::20.0.0.1/32
Label = 120105
NH = cafe:1::1

IP-VRF-SRv6-1
SRv6

SRv6MPLSMPLSPE2
PE1
VPN-IPv4 Route© 2021 Nokia

PE3

Service interworking gateway

30.0.0.1/32
Label = 414206
NH = cafe:1::1
SRv6 SID: cafe:1:0:1::

11

BGP

VPN-IPv4 Route
30.0.0.1/32
Label = 90105
NH = cafe:1::3

segment-routing-v6 {instance 1 {locator “LOC-PE1” {function {end-dt46}}}}
allow-export-bgp-vpn true
bgp-ipvpn {segment-routing-v6 1 {admin-state enablesrv6-instance 1 default-locator “LOC-PE1”
route-distinguisher 1:1
vrf-target {import-community "target:64500:1"
export-community "target:64500:1"}}
mpls {
admin-state enable
route-distinguisher 2:2
vrf-target {import-community "target:64500:1"
export-community "target:64500:1"}
auto-bind-tunnel {resolution any}}}

同一のVPRN(VRF)内で複数のEncapsulationをサポート• VPN IPv4/IPv6 PrefixをSRv6とIPv4/IPv6 MPLSトランスポートドメイン間で転送

Base Routing上でもInterwork Gatewayとして動作• IPv4/IPv6 BGP prefixeを
BGP-LU/6PEとSRv6ドメイン間で転送

EANTC MPLS SDN Interoperability Test 2021
https://eantc.de/showcases/2021/mpls_sdn_interop.html
https://eantc.de/fileadmin/eantc/downloads/events/2021/MPLSSDNInterop/EANTC-MPLSSDNInterop-2021-WhitePaper.pdf

12© 2021 Nokia

Segment Routing関連テストアイテム•13•
Segment Routing• SR-MPLS with VPN Services• L3VPN over SR-MPLS• IPv6 BGP-LU• SRv6 with VPN Services• EVPN VPWS over SRv6
• EVPN Route Type5 over SRv6
• IPv4/IPv6 GRT over SRv6
• L3VPN over SRv6
• SR-MPLS/SRv6 LSP Ping/Traceroute• Segment Routing Anycast Advertisement• TI-LFA• TI-LFA over SR-MPLS•• TI-LFA with Local/Remote SRLG Protection over MPLS
• TI-LFA over SRv6
• Flex-Algo• Underlay ISIS for SR-MPLS with Flex-Algo• Link Delay Measurement in ISIS Underlay• SR-MPLS with Flex-Algo, 128(Low Delay), 129(Exclude blue),130(Low TE metric)• SRv6 with Flex-Algo• Flex-Algo Prefix Metric© 2021 Nokia

EVPN•••••••••••

E-Line Service•••••

PCE-initiated Paths in a Stateful PCE modelFlexible Cross-Connect ServiceIRB – Symmetric/Asymmetric IRB
Proxy MAC-IP Advertisement
E-Tree Service
IGMP ProxyOISM(Optimized Inter-Subnet Multicast)
EVPN and IP-VPN Interworking
EVPN VXLAN and VXLAN Interworking
Seamless EVPN and VPLS
EVPN Fault ManagementSDN
PCC-initiated Paths in a Stateful PCE model

PCE Path Computation with SR-MPLS
PCE Managing SR Policies cia BGP SR-TE NLRI
Dynamic Instantiation of SR Policy*Nokia Participated and Passed

地味に見つかったInterop Issue: Function length 16bitの壁14© 2021 Nokia

SR/SRv6今後の展望+ EVPN-VPLS and MH, SRv6 Policy
高スケールMetro/WANドメイン (SRv6)

PEIPv6 addressing, SRv6 dataplane

7750/7950/FP4/FP5

アクセス/Cost-optimized metro ドメイン (SRv6)

PE

IPv6 addressing, SRv6 dataplane

EVPN-VPLS/VPWS
MPLS-SRv6 Interwork
SRv6 borderrouter7750/7950
FP4/FP5

SRv6/SR-MPLS
backbone

7250-J2

Metro ドメイン (SR-MPLS, BGP SR)PE

IPv6 addressing, SR-MPLS dataplane

7x50

Metro ドメイン (SR-MPLS, LDP, RSVP-TE, BGP-LU)

PE

IPv4 addressing, SR-MPLS/MPLS dataplane

7x50

SR-MPLS borderrouterSRv6 service
gateway

TOR
DC/MEC ドメイン (SRv6)

7750/7950
FP4/FP5

IPv6 addressing, SRv6 dataplane

NFVappliance

DC/MEC ドメイン (VxLAN)

TORInternet (BGP/IPv4/IPv6)

InternetDC
gateway

7750/7950

IPv4 or IPv6 addressing, IP dataplane

SRv6 IX
gateway

7750/7950

IPv4 or IPv6 addressing, IP dataplane
7750/7950
FP4/FP5

SRv6 capable router
SR-MPLS, IP/MPLS router
マーチャントシリコンの機能状況に応じ将来検討

15© 2021 Nokia