Shulou(Shulou.com)06/01 Report--

1. LSA4 ASBR Summary LSA (ASBR summary LSA) and LSA5 Autonomous system external LSA (Autonomous system external LSA) parsing

LSA type advertiser propagates range advertisements content Link IDADV Router remarks LSA1 all routers have the same Area route, topology RIDRID

LSA2DR only MA network with the same Area mask and topology DR IPDR RID

The last ABR of LSA3, the entire OSPF domain route, mask, Metric route, ABR RID route is marked IA

All OSPF domains outside the domain where the last ABRASBR of LSA4 resides

Location of ASBR ASBR RIDABR RID

LSA5ASBR whole OSPF domain external routing protocol routing

ASBR RIDE2 cost values do not accumulate, E1 cost values accumulate

LSA1 Router LSA (Router LSA)

LSA2 Network LSA (Network LSA)

LSA3 Network Summary LSA (Network summary LSA)

LSA4 ASBR Summary LSA (ASBR summary LSA)

LSA5 Autonomous system external LSA (Autonomous system external LSA)

2. Experimental topology

3. Experimental configuration

R1 configuration

Interface Loopback0

Ip address 1.1.1.1 255.255.255.0

Interface Serial0/0

Ip address 12.1.1.1 255.255.255.0

Interface FastEthernet1/0

Ip address 120.1.1.1 255.255.255.0

Router ospf 110

Router-id 8.8.8.1

Network 1.1.1.0 0.0.0.255 area 0

Network 12.1.1.0 0.0.0.255 area 0

Network 120.1.1.0 0.0.0.255 area 0

R2 configuration

Interface Loopback0

Ip address 2.2.2.2 255.255.255.0

Interface Serial0/0

Ip address 12.1.1.2 255.255.255.0

Interface Serial0/1

Ip address 23.1.1.2 255.255.255.0

Interface FastEthernet1/0

Ip address 120.1.1.2 255.255.255.0

Router ospf 110

Router-id 8.8.8.2

Network 2.2.2.0 0.0.0.255 area 0

Network 12.1.1.0 0.0.0.255 area 0

Network 23.1.1.0 0.0.0.255 area 1

Network 120.1.1.0 0.0.0.255 area 0

R3 configuration

Interface Loopback0

Ip address 3.3.3.3 255.255.255.0

Interface Serial0/0

Ip address 34.1.1.3 255.255.255.0

Interface Serial0/1

Ip address 23.1.1.3 255.255.255.0

Router ospf 110

Router-id 8.8.8.3

Redistribute rip subnets

Network 3.3.3.0 0.0.0.255 area 1

Network 23.1.1.0 0.0.0.255 area 1

Router rip

Version 2

Network 34.0.0.0

No auto-summary

R4 configuration

Interface Loopback0

Ip address 4.4.4.4 255.255.255.0

Interface Serial0/0

Ip address 34.1.1.4 255.255.255.0

Router rip

Version 2

Network 4.0.0.0

Network 34.0.0.0

No auto-summary

4. Conclusion verification

LSA4 Link ID is ASBR RID and ADV Router is ABR RID.

LSA5 Link ID is the route and ADV Router is ASBR RID.

The LAS4 advertisement content is the location of the ASBR, and the LSA5 advertisement content is the external routing protocol route.

5. The difference between E2 and E1.

When E2 is the default, the cost of the redistributed routes used remains the same throughout the OSPF domain, E1 is, and the cost value is cumulative.

You can see that the cost value is 20 at this time. We will select metric-type 1 when we redistribute and see the effect.

R3 (config) # router ospf 110

R3 (config-router) # redistribute rip subnets metric-type 1

As you can see, the route indicates that O E2 becomes 0 E1 and the cost value changes.

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