ASBR (rtr4) sh ip ospf | in RFC Supports NSSA (compatible with RFC 3101) sh ip ospf database self-originate OSPF Router with ID (4.4.4.4) (Process ID 1) Router Link States (Area 4) Link ID ADV Router Age Seq# Checksum Link count 4.4.4.4 4.4.4.4 453 0x80000005 0x00541B 3 Type-7 AS External Link States (Area 4) Link ID ADV Router Age Seq# Checksum Tag 172.16.1.0 4.4.4.4 452 0x80000001 0x008FA9 0 172.16.2.0 4.4.4.4 452 0x80000001 0x0084B3 0 sh ip ospf border-routers OSPF Router with ID (4.4.4.4) (Process ID 1) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 3.3.3.3 [1] via 10.1.34.3, GigabitEthernet0/0, ABR/ASBR, Area 4, SPF 5 <-----ABR & ASBR sh ip ospf | in It It is an autonomous system boundary router It is a NSSA area sh ip ospf da nssa-external OSPF Router with ID (4.4.4.4) (Process ID 1) Type-7 AS External Link States (Area 4) LS age: 1601 Options: (No TOS-capability, Type 7/5 translation, DC, Upward) <--- applicable for translation LS Type: AS External Link Link State ID: 172.16.1.0 (External Network Number ) Advertising Router: 4.4.4.4 LS Seq Number: 80000003 Checksum: 0x8BAB Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 LS age: 1601 Options: (No TOS-capability, Type 7/5 translation, DC, Upward) <--- applicable for translation LS Type: AS External Link Link State ID: 172.16.2.0 (External Network Number ) Advertising Router: 4.4.4.4 LS Seq Number: 80000003 Checksum: 0x80B5 Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 ABR (rtr3) ABR translates Type 7 into Type 5 the Forward Address is coppied and is flooded into all other areas so R3 becomes an ASBR! sh ip ospf | in RFC Supports NSSA (compatible with RFC 3101) sh ip ospf border-routers OSPF Router with ID (3.3.3.3) (Process ID 1) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 4.4.4.4 [1] via 10.1.34.4, GigabitEthernet0/0, ASBR, Area 4, SPF 7 <----- ASBR i 2.2.2.2 [1] via 10.1.23.2, GigabitEthernet0/3, ABR, Area 0, SPF 10 sh ip ospf | in It It is an area border and autonomous system boundary router <******** It is a NSSA area sh ip ospf | in Pe Perform type-7/type-5 LSA translation ABR#sh ip ospf database self-originate | be Type-5 Type-5 AS External Link States Link ID ADV Router Age Seq# Checksum Tag 172.16.1.0 3.3.3.3 1862 0x80000001 0x004205 0 172.16.2.0 3.3.3.3 1862 0x80000001 0x00370F 0 sh ip ospf da external OSPF Router with ID (3.3.3.3) (Process ID 1) Type-5 AS External Link States LS age: 5 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 172.16.1.0 (External Network Number ) Advertising Router: 3.3.3.3 LS Seq Number: 80000004 Checksum: 0x3C08 Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 LS age: 5 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 172.16.2.0 (External Network Number ) Advertising Router: 3.3.3.3 LS Seq Number: 80000004 Checksum: 0x3112 Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 rtr2 sh ip ospf | in RFC Supports NSSA (compatible with RFC 3101) rtr2#sh ip ospf border-routers OSPF Router with ID (2.2.2.2) (Process ID 1) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 3.3.3.3 [1] via 10.1.23.3, GigabitEthernet0/3, ABR/ASBR, Area 0, SPF 7 <-----ABR & ASBR sh ip ospf da self-originate | be ASB Summary ASB Link States (Area 2) Link ID ADV Router Age Seq# Checksum 3.3.3.3 2.2.2.2 801 0x80000002 0x00BC69 sh ip route ospf | in E1 E1 - OSPF external type 1, E2 - OSPF external type 2 O E1 172.16.1.0 [110/23] via 10.1.23.3, 00:13:20, GigabitEthernet0/3 O E1 172.16.2.0 [110/23] via 10.1.23.3, 00:13:20, GigabitEthernet0/3 sh ip ospf | in It It is an area border router rtr1# sh ip ospf | in RFC Supports NSSA (compatible with RFC 3101) sh ip ospf border-routers OSPF Router with ID (1.1.1.1) (Process ID 1) Base Topology (MTID 0) Internal Router Routing Table Codes: i - Intra-area route, I - Inter-area route i 2.2.2.2 [1] via 10.1.12.2, GigabitEthernet0/2, ABR, Area 2, SPF 15 i 3.3.3.3 [1] via 10.1.13.3, GigabitEthernet0/1, ABR/ASBR, Area 3, SPF 6 <-----ABR & ASBR sh ip ospf database asbr-summary OSPF Router with ID (1.1.1.1) (Process ID 1) Summary ASB Link States (Area 2) LS age: 264 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(AS Boundary Router) Link State ID: 3.3.3.3 (AS Boundary Router address) Advertising Router: 2.2.2.2 LS Seq Number: 80000002 Checksum: 0xBC69 Length: 28 Network Mask: /0 MTID: 0 Metric: 1 sh ip ospf da external OSPF Router with ID (1.1.1.1) (Process ID 1) Type-5 AS External Link States LS age: 1741 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 172.16.1.0 (External Network Number ) Advertising Router: 3.3.3.3 LS Seq Number: 80000001 Checksum: 0x4205 Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 LS age: 1741 Options: (No TOS-capability, DC, Upward) LS Type: AS External Link Link State ID: 172.16.2.0 (External Network Number ) Advertising Router: 3.3.3.3 LS Seq Number: 80000001 Checksum: 0x370F Length: 36 Network Mask: /24 Metric Type: 1 (Comparable directly to link state metric) MTID: 0 Metric: 20 Forward Address: 4.4.4.4 External Route Tag: 0 sh ip route ospf | in E1 E1 - OSPF external type 1, E2 - OSPF external type 2 O E1 172.16.1.0 [110/23] via 10.1.13.3, 00:06:14, GigabitEthernet0/1 O E1 172.16.2.0 [110/23] via 10.1.13.3, 00:06:14, GigabitEthernet0/1