1. 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 (liulei.kddi@gmail.com) Alvaro Retana (aretana@cisco.com)

2. Page 2 Contents  Smooth Migration to TTZ (new)  Changes to OSPF Protocol  Introduction  Next Step  LSA Change – I bit  TTZ TLV in RI LSA (new)  Operation Simplified (new)

3. Page 3 A group of routers and links connecting routers with same TTZ ID  which is virtualized as a group of TTZ edge routers fully connected or a single router  of which routers outside TTZ are NOT aware Links, routers inside TTZ are NOT advertised to routers outside of TTZ R6 R8 R10 R2 R3 T4 T2 T5 T8 T3 T9 T10 T1 T7 T6 TTZ T4 T3 T10 T1 Definition of TTZ Removed A group of TTZ edge routers

4. Operation Simplified: 1 cmd/router Configurations on router T1: router ospf 1 Interface ethernet 1/0 ip address 10.10.120.1/24 Interface ethernet 2/0 ip address 192.168.20.1/24 ttz 192.168.100.100 Configurations on router T5: router ospf 1 ttz 192.168.100.100 Interface ethernet 3/0 ip address 192.168.30.1/24 No configuration changes on router outside TTZ Configurations on router R2: router ip ospf 1 Interface ethernet 0/0 ip address 10.10.120.1/24 Interface ethernet 1/0 ip address 10.10.220.1/24 Configure TTZ ID on one interface in TTZ for edge R6 R8 R10 R2 R3 T4 T2 T5 T8 T3 T9 T10 T1 T7 T6 TTZ Configure TTZ ID on internal TTZ router Eth0/0 Eth1/0 Eth4/0 Eth3/0 Eth2/0 Eth1/0 Eth2/0 Eth3/0 Eth4/0 Eth0/0Eth1/0 Eth2/0 Eth3/0 Eth4/0 Eth2/0 Eth0/0Eth1/0 Eth0/0 Will Simplify It More

5. Page 5 Contents  Smooth Migration to TTZ (new)  Changes to OSPF Protocol  Introduction  Next Step  LSA Change – I bit  TTZ TLV in RI LSA (new)  Operation Simplified (new)

6. Page 6 LSA Change — I bit 1 bit to identify if a link is in TTZ 0127 I Link Type I = 1 : Link is in TTZ I = 0 : Link is not in TTZ Meaning of “Link Type” of 7 bits is the same as that of “Link Type” of 8 bits. 0127 Link Type OptionsLS Age Link State ID LS Sequence Number LS Checksum Advertising Router Length Number of Links I bit = 1 if link in TTZ LS Type = 1 Router Link... Flags Header I bit = 1 if link in TTZ Router LSA

7. Router LSA Generated by T1/T5 to inside TTZ R6 R7 R8 R10 R9 R4 R1 R2 R11 R3 R5 T4 T2 T5 T8 T3 T9 T10 T1 T7 T6 TTZ OptionsLS Age Link State ID (T1) LS Sequence Number LS Checksum Advertising Router (T1) Length Number of Links I=0 for Normal Link LS Type = 1 Router Link: T1 to R2 Router Link: T1 to T5 Flags Header Router Link: T1 to T2 Router Link: T1 to T4 I=1 for TTZ link OptionsLS Age Link State ID (T5) LS Sequence Number LS Checksum Advertising Router (T5) Length Number of Links I=1 for TTZ Link LS Type = 1 Router Link: T5 to T1 Router Link: T5 to T9 Flags Header Router Link: T5 to T4 Router Link: T5 to T6 I=1 for TTZ link

8. Page 8 Router LSA by T1 for Virtualizing TTZ R6 R7 R8 R10 R9 R4 R1 R2 R11 R3 R5 T4 T3 T10 T1 OptionsLS Age Link State ID (T1) LS Sequence Number LS Checksum Advertising Router (T1) Length Number of Links Normal Link LS Type = 1 Router Link: T1 to R2 Router Link: T1 to T10 Flags Header Router Link: T1 to T3 Router Link: T1 to T4 Normal Link (“virtual”)

9. Page 9 Contents  Smooth Migration to TTZ (new)  Changes to OSPF Protocol  Introduction  Next Step  LSA Change – I bit  TTZ TLV in RI LSA (new)  Operation Simplified (new)

10. Page 10 TTZ TLV in RI LSA TLV for Info of TTZ router 0 1 3 TTZ ID E Length E = 1 : Edge router of TTZ E = 0 : Internal router of TTZ TTZ ID: ID of TTZ to which router belongs 0150 Type OptionsLS Age 4 LS Sequence Number LS Checksum Advertising Router Length LS Type = 10... TLVs Header OSPFv2 Router Information LSA 1 0 TTZ: all routers with same TTZ ID and all TTZ links. For TTZ edge router, its links connected to other TTZ routers are TTZ links. For TTZ Internal router, all its links are TTZ links.

11. RI LSA Generated by T1/T5 R6 R7 R8 R10 R9 R4 R1 R2 R11 R3 R5 T4 T2 T5 T8 T3 T9 T10 T1 T7 T6 TTZ 100 OptionsLS Age 4 LS Sequence Number LS Checksum Advertising Router (T1) Length LS Type = 10 Header TTZ ID = 100 E=1 for Edge of TTZ OptionsLS Age LS Sequence Number LS Checksum Advertising Router (T5) Length LS Type = 10 Header 040 TTZ TLV E=1 TTZ ID = 100 E=0 for Internal router of TTZ TTZ TLV E=0

12. Page 12 Router LSA by T1 for Virtualizing TTZ (Same) R6 R7 R8 R10 R9 R4 R1 R2 R11 R3 R5 T4 T3 T10 T1 OptionsLS Age Link State ID (T1) LS Sequence Number LS Checksum Advertising Router (T1) Length Number of Links Normal Link LS Type = 1 Router Link: T1 to R2 Router Link: T1 to T10 Flags Header Router Link: T1 to T3 Router Link: T1 to T4 Normal Link (“virtual”)

13. Page 13 Contents  Smooth Migration to TTZ (new)  Changes to OSPF Protocol  Introduction  Next Step  LSA Change – I bit  TTZ TLV in RI LSA (new)  Operation Simplified (new)

14. Smooth Migration to TTZ Migration to TTZ with minimum interruption 1.Configure TTZ: routers in TTZ work as normal and prepare for TTZ 2.Allow router to TTZ after it is ready for TTZ 3.Activate TTZ: all routers in TTZ transfer to work as TTZ routers in ms Page 14 R6 R7 R8 R10 R9 R4 R1 R2 R11 R3 R5 T4 T2 T5 T8 T3 T9 T10 T1 T7 T6 TTZ Normal links TTZ link states “viewed” after configure TTZ (LSA with TTZ TLV or LSA with I bit generated and distributed) 2. Allow it to TTZ after it has a complete TTZ topology as configured 3. Activate TTZ after all routers in TTZ are allowed to TTZ. (Generate and distribute LSA for virtualizing TTZ. Transfer to TTZ) Generate and distribute LSA for virtualizing TTZ after receiving LSA. Transfer to TTZ. Normal link TTZ link

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