OSPF Topology-Transparent Zone Huaimo Chen - PowerPoint PPT Presentation

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) ¡

Contents Ø Introduction Ø Operation Simplified (new) Ø Changes to OSPF Protocol § LSA Change – I bit § TTZ TLV in RI LSA (new) Ø Smooth Migration to TTZ (new) Ø Next Step Page 2

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

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

Contents Ø Introduction Ø Operation Simplified (new) Ø Changes to OSPF Protocol § LSA Change – I bit § TTZ TLV in RI LSA (new) Ø Smooth Migration to TTZ (new) Ø Next Step Page 5

LSA Change — I bit 1 bit to identify if a link is in TTZ Router LSA 0 1 2 7 LS Age Options LS Type = 1 Link Type Link State ID Header Advertising Router LS Sequence Number LS Checksum Length Flags Number of Links 0 1 2 7 I bit = 1 if Router Link link in TTZ Link Type I . . . . . . I bit = 1 if link in TTZ Router Link 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. Page 6

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

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

Contents Ø Introduction Ø Operation Simplified (new) Ø Changes to OSPF Protocol § LSA Change – I bit § TTZ TLV in RI LSA (new) Ø Smooth Migration to TTZ (new) Ø Next Step Page 9

TTZ TLV in RI LSA TLV for Info of TTZ router OSPFv2 Router Information LSA 0 1 3 0 1 5 0 1 LS Age Options LS Type = 10 Type Length 4 0 Header Advertising Router E LS Sequence Number LS Checksum Length TTZ ID TLVs . . . . . . E = 1 : Edge router of TTZ E = 0 : Internal router of TTZ TTZ ID: ID of TTZ to which router belongs 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. Page 10

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

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

Contents Ø Introduction Ø Operation Simplified (new) Ø Changes to OSPF Protocol § LSA Change – I bit § TTZ TLV in RI LSA (new) Ø Smooth Migration to TTZ (new) Ø Next Step Page 13

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

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