1. NOC Lessons Learned TEIN2 and CERNET Xing Li 2007-01-22

2. NOC Outline Introduction TEIN2 routing policy CERNET BGP Experience Lessons learned

3. NOC Simple Case (where BGP can handle things easily) Global transit –To tier 1 or tier 2 commodity networks Care the aggregation Care the load balancing Don’t care the symmetry Peering (no transit, except for the down streams) –To domestic ISPs (bi-literal or via IX) Care the business model –To academic partners Care the performance Care the symmetry

4. NOC Complicated Case (where BGP cannot handle things easily) Global transit –To tier 1 or tier 2 commodity networks Care the aggregation Care the load balancing Don’t care the symmetry Academic transit –To multiple transit backbones within academic scope Care the aggregation Care the load balancing Care the performance Care the symmetry Etc. Peering (no transit, except for the down streams) –To domestic ISPs (bi-literal or via IX) Care the business model –To academic partners Care the performance Care the symmetry

5. NOC Two Steps to Implement the Policy Identification –IP prefix –AS path regular expression –Community tag Path selection –AS path (inbound and outbound) –Local-preference (outbound) –More specific (inbound)

6. NOC For Transit Network TEIN2 Example

7. NOC TEIN2 Topology

8. NOC The Principle of Routing Design for the TEIN2 network To provide interconnection among TEIN2 partners and between TEIN2 partners and EU NRENs. To provide back-up paths within the TEIN2 network and/or via partner networks for service resilience when possible. To provide a flexible and transparent routing policy to TEIN2 NRENs. To avoid being selected by GÉANT, Abilene and other R&E networks outside TEIN2 as the preferred transit network. To minimize the adjustment of the external peers’ routing policy outside TEIN2 networks, e.g. GÉANT and APAN.

9. NOC TEIN2 Routing Policy Enable additive community tagging to mark the prefix announcements. Adopt AS number prepending as the preferred BGP policy for TEIN2 traffic adjustment within TEIN2 backbone. –Use ingress AS number prepending for outbound traffic adjustment, including traffic from TEIN2 POP to NRENs, GÉANT and APAN. –Use egress AS number prepending for inbound traffic adjustment, including traffic from NRENs, GÉANT and APAN to TEIN2 POP. May use Local-Preference amendment as the last resort of mechanism for fine tuning on TEIN2 traffic over the backbone.

10. NOC For NRN CERNET Example

11. NOC CERNET Topology

12. NOC CERNET Peering CERNET TEIN2 STARLIGHT HARNET ASNET DRAGONLIGHT CNGI-BJIX DRAGONTAP CERNET 2 Internet Domestic Peering CNGI Peering APAN KOREN 3 G 12G 155M 100M 1G 155M 2x155M 622M 10G

13. NOC CERNET Routing Policy Outbound –Use AS number prepending if possible –Heavily use Local-Preference –Enable additive community tagging to mark the prefixes Inbound –Use AS number prepending if possible –Announce more specifics –Enable additive community tagging to mark the prefixes

14. NOC Case 1 TAIWAN Earthquake

15. NOC Earthquake on 26th DEC 2006

16. NOC Why did not include this policy before the earthquake?

17. NOC Case 2 Routing and End-to-end performance

18. NOC Ping and dvping beacons

19. NOC Here in the APAN venue WLAN

20. NOC Lessons Learned (1) The nature of BGP is reachability –Stupid routing happen –Policy based routing makes thing very complicated –The routing and topology are very dynamic environment The key words are: simple, open and controllability –For transit network Simple Open –For NRN Simple Controllability Why did not include this policy before the earthquake? –Because it is a NP problem and there are many contradict requirements –Mission impossible –What should be the solution?

21. NOC Lessons Learned (2) It seems that we still need to do a lot manual BGP policy adjustment, case by case with the help of –Multi-site collaborations –Routeviews We have to compare the routing table with the end-to-end performance matrix –dvping tool