Segment Routing at IETF102
そして今後のネットワークアーキテクチャへの一考察

31 August 2018
Miya Kohno, Distinguished Systems Engineer, Cisco Systems

Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

Cisco Confidential

Segment Routingが取り上げられたWG in IETF102 (1/3)
WG

Discussion Items

SPRING (Source Packet Routing inNetworking)Segment Routing 関連技術全般• YANG model• SR Policy (Traffic Engineering)• NSH/SR Integration• Service Programming (Service Chaining)• SRv6 Network Programming• Node Protection for SR-TE path
• Ping for Flex Algorithm prefix• SR for SD-WAN• OAM• Traffic Accounting• Performance Measurement

6man (IPv6 Maintenance)••© 2018 Cisco and/or its affiliates. All rights reserved.

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SRv6 SR Header
SRv6 OAM

Segment Routingが取り上げられたWG in IETF102 (2/3)
WG

Discussion Items

LSR (Link State Routing)•••

IS-IS extension for SRv6
SR Flex Algorithm
IGP extension for SR based enhanced VPN

DMM (Distributed MobilityManagement)•••

SRv6 for mobile user plane
SRv6 as Data Plane for mobile packet core
SRv6 for mobile user plane – PoC report

IDR (Inter Domain Routing)••

SR Policies for Path Segment and Bi-directional PathSR Policies for Path Segment and Bi-directional Pathfor BGP-LS

PIM (Protocol Independent Multicast)•

A Framework for Computed Multicast applied toSR-MPLS

BIER (Bit Indexed Explicit Replication)•MVPN using Segment Routing and BIER

© 2018 Cisco and/or its affiliates. All rights reserved.

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Segment Routingが取り上げられたWG in IETF102 (3/3)
WG

Discussion Items

MPLS (Multi Protocol Label Switching)•Ping for Flex Algorithm prefix

LISP (Locator ID Separation Protocol)•

LISP Control Plane for SRv6

RTGWG (Routing Working Group)•SRv6 Constrain Analysis

SFC (Service Function Chaining)••

SR for Service Programming
NSH/SR Integration

11 WGs, 28 items !!!
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Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

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Building blocks (SR centric) for enabling slices• Segment Routing Policy
•
••
•••
•
•

Flex-Algorithm based SR Policy
On demand SR Policy
Automatic Steering
Inter-domain considerations

TI-LFA and microloop avoidance
SR VPN
Stateless Service Programming
Operations, Administration, and Maintenance• QoS• Orchestration at the Controller© 2018 Cisco and/or its affiliates. All rights reserved.

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https://tools.ietf.org/html/draft-ali-spring-network-slicing-building-blocks-00

Automation/Orchestration for enabling slices

Service Orchestration for
Slice - A

Slice - A

Service Orchestration for
Slice - B

Slice - B

Service Orchestration forBase Infrastructure

Base Infrastructure© 2018 Cisco and/or its affiliates. All rights reserved.

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Flex-Algo mechanisms• Each node MUST advertise Flex-Algo(s) that it participates in
Nodes 0 and 9 participate to Algo 0 and 128 and 129
1

Nodes 1/2/3/4 participate to Algo 0 and 128
Nodes 5/6/7/8 participate to Algo 0 and 129

40• Node N computes Flex-Algo K if it is enabled for K
Node prunes any links excluded by algo K• Installs prefixes into forwarding tables© 2018 Cisco and/or its affiliates. All rights reserved.

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967

1
40Alg1282390
58Computes shortest path38

Node 2 advertises
Prefix SID 16802 for ALGO 128

Alg05• Each node may advertise a prefix per algo
Prefix SID 16002 for ALGO 02Alg129967

Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

Cisco ConfidentialService Chaining with NSH

Network Service HeaderPros:• アンダーレイは問わない

Cons• 各Service Chain参加ノードにおいてステート保持の必要© 2018 Cisco and/or its affiliates. All rights reserved.

Cisco ConfidentialService Chaining with SRv6 (SRv6 Service Programming)

S3

S1

D

SR: 〈S1, C1, S2, S3, D〉
C1

Pros:
• サービスはSegmentとして表現される

à Flexible, Stateless, Scalable

Cons:• SRv6が必要© 2018 Cisco and/or its affiliates. All rights reserved.

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S2

SR and NSH integration?!

© 2018 Cisco and/or its affiliates. All rights reserved.

slides-102-sfc-nsh-and-segment-routing-integration-for-service-function-chaining-sfc-01

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Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

Cisco ConfidentialICN communication principles• Packets say ‘what’ not‘where’ (no addresses)• Pull-based model
controlled by consumer• No connections• Dynamic in-network
forwarding decisions• in-network storage© 2018 Cisco and/or its affiliates. All rights reserved.

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hICN (hybrid ICN) とはCommunicationprinciples

IPhICNICN

Names

Location-dependent
Identifiers in IP addr

Location-independent
Identifiers in IP addr

Location-independent
Identifiers in new pkt format

Request routing

L4-L7 end to end

L3 hop-by-hop

L3 hop-by-hop

TransportConnection-based
Sender-driven

Connection-lessReceiver-driven

Connection-lessReceiver-driven

Mobility

Anchor-based

Anchor-lessAnchor-lessSecurity

Connection/Tunnel-based

Object-based

Object-based

Caching

Application-layer
proactive caching

In-path reactive andproactive caching

In-path reactive andproactive caching© 2018 Cisco and/or its affiliates. All rights reserved.

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hICN - IETF drafts!

© 2018 Cisco and/or its affiliates. All rights reserved.

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Mobility Architectures
Locator-based
Mapping information
ID
UE#1

ID
UE#1
UE#2

/c1 /c2 = content prefixes (eg. b001::/64)

Mapping System

Mapping information

GTP
GTP#1

ID-based

ID/Loc separation
ID
UE#1
DN#2
...

GTP
GTP#2
GTP#3

Locator
UPF#1
UPF#4
...

hICN FIB

UE#1

UPF#1

GTP#1

UPF#3

DN#1

node id #1

UE#1

UPF#1

UPF#3

DN#1

UE#2

UPF#2

GTP#3

UPF#4

DN#2

node id #2

UE#2

UPF#2

UPF#4

DN#2/c2Name/c1Faces
FW St
UPF#1, LoadBal.
UPF#2

UE#1

UPF#1

UE#2

UPF#2

hICN FIB
Name/c1/c2Faces
FW St
UPF#2 Min. Lat.
UPF#2 Min. Lat.

UPF#3

DN#1/c1

UPF#4

DN#2/c1/c1

Decentralized; control plane sig.

§•
•
•

•

GTP-U
SRv6

Locators used as identifiers: semanticoverloading that complexifies mobility(anchors/tunnels)
Lack of flexibility, complex management ofsynch, does not allow dynamic offload atedge© 2018 Cisco and/or its affiliates. All rights reserved.

Decentralized; control plane sig.

••••

Mapping system where to keep
udpated / verify Loc/ID binding•

Challenges : scalability, latency for theverification, issues in caching andsynchronization of a distributed
mapping system

Cisco Confidential•

LISP (ILSR/ILNP)
ILASRv6•

Fully distributed; forwarding plane sig.

••
•
•••
••

(draft-vonhugo-5gandip-ip-issues-03)

ICN
hICN

no anchors (neither in UP nor in CP)
No operation for static/mobile cons.
latency-optimized user plane updates
access-agnostic approachseamless integration of hetnet
IETF102資料より

Complimentary Roles: hICN & SRv6
Hybrid ICN

Other Control Planes ..

Control

Path State

VTS, BGP, IGP, XTC, GTP-C, SBA

Anchorless Endpoint Mobility
Content Security
Multi-HomingAsynchronous “Multicast”

SRv6 (Source Routing, Segmentation)
Service Chaining
Source Vectoring

Multi-Path

Segment Identification
Distributed Control

Anchorless Application
Asynchronous Control Plane
Stateless L4 Transport
Leverage Native FIB

RecoveryCaching

FRRIPv6Forwarding© 2018 Cisco and/or its affiliates. All rights reserved.

Path Recovery
End-point Addressing
Topological Forwarding State
Open Source Community
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Host / VM / Container Identification
Standards Based Support
Underlay Management
Basic Services Support

Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

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Simplification – Protocol reduction
MPLS

Services

Transport

MPLS SR (SDN)

BGP

Services

T-LDP

BGP-LU
RSVP-TE
MPLS LDP
IGP
IP/MPLS© 2018 Cisco and/or its affiliates. All rights reserved.

BGP

SRv6 (SDN)

Services

T-LDP

Net
Program

SDN
Transport

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IGP/SR
IP/MPLS

SDN
Transport

IGP
IPv6/SR* SDN for Service Orchestration, Automation

Simplification – State reduction
http://www.itmedia.co.jp/mobile/articles/1805/24/
news143.html

https://blog.apnic.net/2018/03/07/reducingcomplexity-5g-networks-using-segment-routingipv6/© 2018 Cisco and/or its affiliates. All rights reserved.

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Simplification – Control plane/User plane separation
slides-102-rtgwg-sessb-draft-wadhwa-rtgwg-bng-cups-01

Control Planeを分離し、User Planeをシンプル化、ステートレス化することによって© 柔軟な構成とScale2018 Cisco and/or its affiliates. All rights
reserved. Cisco Confidential
Outを実現Simplification – Overlay/Underlay separation ?!

ServiceControl

ServiceControl

Transport Policy &Optimisation

Underlay Agnostic
Service Layer

Transport Layer

Service Un-aware© 2018 Cisco and/or its affiliates. All rights reserved.

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Agenda• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

Cisco Confidential現在のコミュニケーションモデル
• Mobility, Content, Load Balancing, Securityはネットワークアーキテクチャに組み込まれておらず、付加的に実装
à Overlay/Tunnelの蔓延§

Various/uncoordinated security- Security- Load Balancing- Content
Distribution- Mobility§

Session Load Balancing§

Storage – Pre-Positioned
Cache/Storage§- Network© 2018 Cisco and/or its affiliates. All rights reserved.

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Security – End 2 End crypto,

Mobility – Sub-Optimal / Anchor
based, inconsistent withheterogeneous accessICNモデルInformation Awareなネットワーク, Not Where -> WHAT

Integrated to Single Layer• Mobility, Content, Load Balancing, Security• à ネットワークアーキテクチャへの基本的な組み込み

A New Network Foundation© 2018 Cisco and/or its affiliates. All rights reserved.

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Security – Object Based Security,§Intelligent Load Balancing - perapp and at every hop§

Storage – Dynamic Store/cachingof Objects in the forwarding fabric§

Mobility – Optimal, No Anchors§ Networking on Named Data

Enable rapid loss recovery, optimal congestion
control, consistent Unicast/Multicast,
per apps/name forwarding strategy

SRv6 for underlay

SRv6 for Underlay
IPv6 for reach© 2018 Cisco and/or its affiliates. All rights reserved.

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Simplification, FRR, TE, SDN

SRv6 - Opportunity for further simplification
NSH for NFVAdditional Protocol and State

UDP+VxLAN OverlayAdditional Protocol just for tenant ID

SRv6 for Underlay

Simplification, FRR, TE, SDN

IPv6 for reach• Multiplicity of protocols and states hinder network economics© 2018 Cisco and/or its affiliates. All rights reserved.

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Overlay/Underlay -- Separated or Integrated?
SeparatedIntegrated• VXLAN• SRv6 Net Programming• NSH• SRv6 Service Programming• SD-WAN + SR integration• SD-WAN• GTP tunnel• SRv6 Mobility…

• (h)ICN• SLA aware Network Slicing© 2018 Cisco and/or its affiliates. All rights reserved.

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Integrated Modelへの批判：- Underlay InfraがIPv6に限られてしまう！

hICN Insertions Points (例)Origin ServerOrigin ServerPartner Content
CS

Compute Resources
CUPS extends PGW-UP
to CRANV6 only hICN APN
HICN Clients
IPv6RRH

BBU

CSR

RRH

hICN
Domain© 2018 Cisco and/or its affiliates. All rights reserved. Cisco Confidential

CS

Peer

VCP-Edge for Compute
Resources
PGW for CP
V6 only APN for hICNSP Content
CS

CS

CS

Peer
Wireless Access

6VPE

CPUPvPC

HICN-Proxy

IPv4 Core

HICN-F

EBH

6VPE

6VPE

CS CS

CS CS
HICN-FRRHCSeNSE

IPv6 Domain(over IPv4!!)

6VPE

ProducerCS

HICN-Producer

VCP-Core forcompute resources
hICN
DomainIPv6 centric networkへ

IPv6 centric network• ドメインを越えたデータプレーンの統一• Native(No more Tunnel/Overlay), Stateless, Simple• IPv4 as a Service, no more VLAN as an ID© 2018 Cisco and/or its affiliates. All rights reserved.

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まとめ• Segment Routingが取り上げられたWG• IETF102におけるハイライト• Flex Algo for Network Slicing• SRv6 と NSH• SRv6 と hICN
• 今後のネットワークアーキテクチャへの一考察• Simplification• Overlay/Underlay – Separation or Integration?
© 2018 Cisco and/or its affiliates. All rights reserved.

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