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This briefing provides an overview of CERNET2, the largest backbone of CNGI project running on top of CERNET Transport network. It discusses CERNET2's IPv4 over IPv6 requirement, configurations, and the vision for supporting existing IPv4 access networks and applications.
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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
HeiLongJiang JiLin 长春 NeiMengGu 北京 XinJiang 沈阳 LiaoNing GanSu 天津 大连 HeBei ShanDong NingXia 青岛 ShanXi ShaanXi 济南 QingHai 兰州 HeNan JiangSu 南京 AnHui 郑州 西安 SiChuan 武汉 上海 XiZang 合肥 成都 重庆 HuBei 杭州 ZheJiang JiangXi 长沙 FuJian 福州 HuNan GuiZhou 昆明 台湾 GuangDong 厦门 GuangXi CERNET CERNET YunNan 深圳 ChinaTelecom 广州 香港 CNC/CST HaiNan ChinaMobile Unicom ChinaRail CNGI Backbones
SY SY chc chc hrb hrb 沈阳 沈阳 哈尔滨 哈尔滨 天津 天津 北京 北京 BJ BJ dln dln lzh 大连 大连 tjn 济南 济南 太原 太原 石家庄 石家庄 青岛 青岛 XA XA zhz zhz jnn 郑州 郑州 CD CD chq chq WH WH hef hef NJ NJ SH SH 重庆 重庆 南京 南京 上海 上海 成都 成都 武汉 武汉 合肥 合肥 南昌 南昌 chs chs hzh hzh 杭州 杭州 长沙 长沙 桂林 桂林 GZ GZ xmn xmn 南宁 南宁 厦门 厦门 福州 福州 广州 广州 昆明 昆明 深圳 深圳 海口 海口 CERNET Transport Network
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
High Throughput Video Multicast Video CERNET2’s IPv4 over IPv6 App. Requirement
CERNET2’s Vision • IPv4 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
Global IPv4 Internet v4 BJ SH v4 GZ Allow manual configuration Must support unicast and multicast v4 Only BJ, SH and GZ provide IPv4 service Other nodes are IPv6 only Configuration (1)
Global IPv4 Internet v4 v4 v4 v4 SY chc hrb v4 BJ tjn dln jnn v4 v4 v4 lzh v4 zhz v4 XA v4 hrf v4 CD SH chq WH NJ SH v4 v4 v4 v4 chs hzh v4 GZ xmn v4 v4 Prefer auto-configuration Must support unicast and multicast All Pops provide IPv4 service Configuration (2)
Same as a dual-stack backbone softwire IPv4 static or eBGP peering Encapsulation and Setup IPv4 Access IPv4 Access edge edge CERNET2 Backbone IPv4 Access IPv4 Access edge edge IPv6 Access IPv6 Access Pure IPv6 backbone Access Network’s View
Same behavior as a dual-stack backbone softwire IPv4 static or eBGP peering Encapsulation and Setup IPv4 access island IPv4 access island AFBR AFBR IPv6 Transit IPv4 access island IPv4 access island AFBR AFBR IPv6 access IPv6 access Softwire Mesh Scenarios (IPv4/IPv6)
Same behavior as a dual-stack backbone Softwire IPv6 static or eBGP peering Encapsulation and Setup IPv6 access island IPv6 access island AFBR AFBR IPv4 Transit IPv6 access island IPv6 access island AFBR AFBR IPv4 access IPv4 access Softwire Mesh Scenarios (IPv6/IPv4)
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 connected 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, cross AS’s mechanism is desirable • Encapsulation and control protocol includes • Encapsulation type • End point setup • MTU • Management requires • MIB