Applicability of OSPF Topology-Transparent Zone

1. Applicability of OSPF Topology-Transparent Zone Huaimo Chen (huaimochen@huawei.com) Renwei Li (renweili@huawei.com) Gregory Cauchie (greg.cauchie@gmail.com) Ning So (ning.so@tatacommunications.com) Lei Liu (le-liu@kddilabs.jp)

2. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 2

3. Introduction • What will happen if number of routers in AS is bigger and bigger? • Operation is harder when split into areas further (Network Architecture changes) • It is difficult for a MPLS TE LSP crossing areas to be established • Route convergence is slower • Show how TTZ resolve these issues Page 3

4. T3 T3 T2 T1 T1 T6 T5 T7 T9 T4 T4 T8 T10 T10 TTZ What is TTZ? R6 R1 R2 R7 R8 R9 R3 R10 R4 R5 R11 • A group of routers connected by links withattribute TTZ ID. • Routers outside of TTZ are NOT aware of TTZ, just see the edge routers of TTZ, which are connected. • Links, routers inside TTZ are NOT advertised to routers outside of TTZ.

5. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 5

6. One Area Network Area 4 Area 1 R5 T3 R5 T3 T2 T2 T1 R1 R6 T1 R1 R6 T6 T6 T5 T7 T5 T7 R7 R7 T9 T9 R2 R2 T4 R8 T4 T8 R8 T8 R3 R3 T10 Area 0 T10 R9 R9 R4 R4 Area 3 R10 R10 Area 0 Area 2 Issues on Splitting Network into Areas: Significant changes on Network Architecture and configurations Complex for E2E TE LSP crossing areas to be set up Policy Configurations and Slow Convergence Page 6

7. Use of TTZ in One Area Network T3 T3 T3 T3 T3 T3 T3 T2 T3 T3 T3 T1 T6 T1 T T T5 T7 T9 T4 T8 T4 T10 T10 T10 T10 T10 T10 T10 TTZ 1 T10 T Area 0 1. No Significant Changes on Network Architecture (No need to split area) 2. TE LSP can be set up easily 3. No Policy Configurations and Fast Convergence Page 7

8. E2E TE LSP can be set up easily T3 T2 T3 T1 T6 T1 T5 T7 T9 T4 T8 T4 T10 TTZ T10 R5 R1 R6 R7 Destination R8 R2 R9 R3 Source R4 R10 Find path from R3 to R6 in a normal way Find path from T4 to T10 in a normal way Path for LSP is computed easily in a normal way LSP can be set up along the path computed Page 8

9. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 9

10. Multi-Area Network Area4 Area 7 Area4 Area 5 Area1 Area1 T7 Area0 Area 3 Area0 Area 2 Area 3 Area 6 Area2 • What happens when splitting a multi-area network into more areas? • Significant Changes on Network Architecture (Re-arranging & splitting areas) • More Configurations for Tunnel Setup • More Policy Configurations Page 10

11. Use of TTZ in Multi-Area Network Area 4 Area 1 T3 T2 T1 R1 T6 T5 T7 R7 T9 R2 T4 T8 R3 T10 Area 0 R9 R4 Area 3 R10 Area 2 1. No big changes on Network Architecture (No need to split areas) 2. No Extra Configurations for Tunnel Setup 3. No More Policy Configurations Page 11

12. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 12

13. Use of TTZ in IPRAN Area 0 T3 T2 Area 1 T1 R4 R1 BSC/RNC T6 T5 T7 T9 R2 T4 T10 R3 T3 Area 0 T2 R4 T1 R1 BSC/RNC T6 T5 T7 T9 TTZ R2 R3 T10 T4 Convert network into backbone area 0 via TTZ 1. Easy E2E TE LSP Setup over optimal path 2. TE LSP within one area can be easily protected using FRR 3. Operation is easier Page 13

14. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 14

15. Use of TTZ for POP T3 T3 T3 T3 T3 T3 T3 T T T T10 T10 T10 T10 POP 3 T3 T2 POP 1 T1 T6 TTZ 3 T5 T7 TTZ 1 T9 T4 T8 POP 2 POP 4 T10 TTZ 2 TTZ 4 1. Increase the network scalability 2. Improve the network availability Page 15

16. Contents • Introduction • Applicability of TTZ • One Area Network • Multiple Area Network • Use of TTZ in IPRAN • Use of TTZ for POP • Deployment Considerations Page 16

17. Deployment Considerations • Number of edge routers of a TTZ should besmall • A TTZ is within an OSPF area

18. Next Step • Welcome comments