Softwire Mesh ExampleCERNET2

Xing Li

<2005-11-07>

Outline

CERNET2 Briefing

CERNET2’s IPv4 over IPv6 requirement

Configurations

Summary

CERNET2 Briefing

CERNET2 is the largest backbone of CNGI

project

CERNET2 is running on top of CERNET

Transport network

CERNET2 is a “pure IPv6” backbone

The users of CERNET2 require high

performance IPv4 applications

CNGI Backbones

XinJiang

XiZang

兰州

NeiMengGu

NingXia

西安

ShanXi

HeBei

郑州武汉

南京

合肥上海

YunNan

GuiZhou

长沙 JiangXi

厦门GuangXi

HaiNan

长春JiLin

大连

台湾深圳

成都

QingHai 济南

重庆

CERNET ChinaTelecom CNC/CST

ChinaMobileUnicom

CERNET

杭州

福州

沈阳

青岛

天津

香港

HeiLongJiang

LiaoNing

北京

ShanDong

JiangSu

ZheJiang

FuJian

GuangDong

HuNan

HuBei

HeNan

AnHui

ShaanXi

GanSu

SiChuan

ChinaRail

昆明

广州

CERNET Transport Network

大连

北京

郑州

石家庄

武汉 合

肥

南京

上海

长沙

南昌 杭

州

广州

福州

成都

昆明

重庆

厦门

海口

桂林

沈阳

哈尔滨

天津

济南

南宁

深圳

太原

青岛

BJ

zhzXA

CD WH

GZ xmn

hzh

SHNJhef

dlnSY chc hrb

chq

chs

大连

北京

郑州

石家庄

武汉 合

肥

南京

上海

长沙

南昌 杭

州

广州

福州

成都

昆明

重庆

厦门

海口

桂林

沈阳

哈尔滨

天津

济南

南宁

深圳

太原

青岛

BJ

zhzXA

CD WH

GZ xmn

hzh

SHNJhef

dlnSY chc hrb

chq

chs

tjn

jnn

lzh

CERNET2 IPv6 Technical Specification

25 Pops in 20 cities linked via 2.5Gbps to 10 Gbps

trunks

IPv6 only Backbone AS23910

2001:DA8::/32

IGP - OSPFv3

EGP - BGP4+ peering with

• 25 regional Pops

• 5 CNGI backbones

• CERNET IPv6, CJ-IPv6, NSFCNET, 863-testbed, 3Tnet, etc

100+ access networks

CERNET2 Topology

CERNET2 Peering

CERNET2’s IPv4 over IPv6 App. Requirement

High Throughput Video

Multicast Video

CERNET2’s VisionIPv4 over IPv6 may help

Built and/or upgrade a backbone without

worrying the limited IPv4 address, have a better

performance-to-cost ratio and in a “politically

correct” manner

Support existing IPv4 access networks

Support existing IPv4 applications

And it may help for the transition from IPv4

to IPv6 in a cost effective, incremental and

seamless fashion

Configuration (1)

v4

v4

v4

BJ

GZ

SH

Only BJ, SH and GZ provide IPv4 serviceOther nodes are IPv6 only

Allow manual configurationMust support unicast and multicast

Global IPv4 Internet

Configuration (2)

v4

v4

v4

BJ

GZ

SH

All Pops provide IPv4 service

hzh

xmn

WH NJ

hrf

jnn

SY

dln

chc hrb

zhzXA

CD SHchq

lzh

v4

v4

v4

v4v4v4

v4v4 v4

v4 v4 v4

v4

v4v4

Prefer auto-configurationMust support unicast and multicast

chs

tjn v4

Global IPv4 Internet

Access Network’s View

CERNET2 Backboneedgeedge

edge edge

IPv4 Access

IPv4 Access

IPv4 Access

IPv4 Access

IPv6 Access IPv6 Access

IPv4 static or eBGP peering Encapsulation and Setup

Same as a dual-stack

backbone

Pure IPv6backbone

softwire

Softwire Mesh Scenarios (IPv4/IPv6)

IPv6 TransitAFBRAFBR

AFBR AFBR

IPv4 accessisland

IPv4 accessisland

IPv4 accessisland

IPv4 accessisland

IPv6 access IPv6 access

IPv4 static or eBGP peering Encapsulation and Setup

Same behavior as a dual-stack

backbonesoftwire

Softwire Mesh Scenarios (IPv6/IPv4)

IPv4 TransitAFBRAFBR

AFBR AFBR

IPv6 accessisland

IPv6 accessisland

IPv6 accessisland

IPv6 accessisland

IPv4 access IPv4 access

IPv6 static or eBGP peering Encapsulation and Setup

Same behavior as a dual-stack

backboneSoftwire

Notes Typical number of Ps, PEs, and CPEs?

P 20 (today) : 50 (CERNET2)

PE 10 (today) : 100 (CERNET2)

CPE 100 (today) : X0000 (CERNET2)

Why not use CPE to provide the functionality? ISP business considerations

Why not use layer 2 service? Point to point scalability and multi-point to multi-point broadcast storm

Configuration on operational overhead

Mesh problem more similar to L3 VPN case

Why not run dual stack on P routers Political and economical considerations

Need to get to V6 only network

Summary IPv4 over IPv6 service should support

The IPv4 access network should behave as if it is connecte

d to a IPv4 or dual-stack backbone

It should support both IPv4 unicast and multicast

Initial requirement is inside an AS domain, but if possible, c

ross AS’s mechanism is desirable

Encapsulation and control protocol includes Encapsulation type

End point setup

MTU

Management requires MIB