NSSA and Type 7/5 Translation

Hello,

This question deals with Workbook 1, Section 6 - OSPF, Task 6.27 NSSA.

Initially I only shutdown R6's VLAN 146 Ethernet interface and did not shutdown Loopback0 by accident. This prevented Type7/Type5 translation. When I looked at the Type 7 LSA on R3 I saw this:

Rack1R3#sho ip ospf data nssa-external 200.0.0.0

            OSPF Router with ID (150.1.3.3) (Process ID 1)

                Type-7 AS External Link States (Area 2)

  Routing Bit Set on this LSA
  LS age: 945
  Options: (No TOS-capability, No Type 7/5 translation, DC)
  LS Type: AS External Link
  Link State ID: 200.0.0.0 (External Network Number )
  Advertising Router: 150.1.6.6
  LS Seq Number: 80000001
  Checksum: 0xF73A
  Length: 36
  Network Mask: /24
        Metric Type: 2 (Larger than any link state path)
        TOS: 0
        Metric: 20
        Forward Address: 0.0.0.0
        External Route Tag: 0

 

Why did having the Loopback 0 (which is in area 1) up cause this to occur?

 

Thanks,

Drew

Comments

  • Hello,

    This question deals with Workbook 1, Section 6 - OSPF, Task 6.27 NSSA.

    Initially I only shutdown R6's VLAN 146 Ethernet interface and did not shutdown Loopback0 by accident. This prevented Type7/Type5 translation. When I looked at the Type 7 LSA on R3 I saw this:

    Why did having the Loopback 0 (which is in area 1) up cause this to occur?

    Thanks,

    Drew

    Not sure if I clearly understood your question. The R3 should also have type-7 LSA in order to perform translation between type-7 & type-5 LSA since it's an ABR which connects a NSSA with the transit area. So, for allowing external routes to transit the stub, it sould be configured as NSSA.

    Hope this helps!

Sign In or Register to comment.