4.6, 4.7, 4.8 related tasks, smth miswritten in WB ?

Hi,

I understand that 4.6-8 tasks are related to each other and the goal is to get R4's loopback as a /24 in R5 routing table.

OK, but how to do this because :

- R5 doesn't have OSPF enabled on serial 0/1/0 ?

I enabled it, disabled peer neighbor route on p2p serial links between R4 and R5 but the  summarization doesn't work for some reason, it gets as a /32 route in R5's routing table (4.6 task)

- ensure neighbor relationship between R4-R5 on the back2back serial connection... well I did this ... but as I said, R4's loopback 0 reaches R5 as a /32

In the SG, OSPF is being enabled on R4's serial0/0/0. what for ???? R2 doesn't have it's FR interface enabled for OSPF, in fact they're running EIGRP. SO, what's the reason ??

I still think my approach is the lucky one but not final as I mentioned.

I would appreciate any comments on this.

 

Thanks so much,

Ciprian.

 

EDIT : Forgot to say that in the diagram provided, an OSPF adj is drawn between R4 and R5, but no area defined ? Is it possible ?

Thanks !

Comments

  • I understand that 4.6-8 tasks are related to each other and the goal is to get R4's loopback as a /24 in R5 routing table.

    OK, but how to do this because :

    - R5 doesn't have OSPF enabled on serial 0/1/0 ?

     

    Hi Ciprian,

    You should advertise the network using either "network" command or you can enable OSPF directly in the interface. So, either of these configuration should be done in order to get your OSPF neighborship up. It means you need to enable OSPF in s0/1/0 interface since you are not allowed use "network" command for this particular task.

     

    I enabled it, disabled peer neighbor route on p2p serial links between R4 and R5 but the  summarization doesn't work for some reason, it gets as a /32 route in R5's routing table (4.6 task)

    In order for a summarization to work, you should have configured it on the ABR as the "area x range" command is used when you need inter-area summarization. So, just configure the point-to-point link in "area 0" & advertise 155.1.4.4 network into area 4. Once you summarize this network into /24 block, R5 can see the /24 network as required.

     

    In the SG, OSPF is being enabled on R4's serial0/0/0. what for ???? R2 doesn't have it's FR interface enabled for OSPF, in fact they're running EIGRP. SO, what's the reason ??

    Since the s0/0/0 interface was to be referenced for "ip unnumbered" command on interface s0/1/0 on R4, you would have to enable OSPF for that particular interface. Otherwise, your OSPF neighborship wouldn't come up. :)

    Hope this helps!

     

  • Hi Hari,

    well now all makes sense, you seem to be for me like was the apple for Newton scientist ;)

    So, here it's the story, in my words now, for future readings :

    - I configured the loopbacks for the unnumbered p2p serial conection between r4 and r5, and obviously enabling Ospf of FR link didn't make sense :)) BUT this is a good point, that OSPF or the running protocol should be enabled on the interface used in the unnumbered configuration.

    - Next, is the ABR summarization; well yes all the routers in an area should hAve the same DB, SO the summarization is configured on True ABRs, meaning they have at least one area 0 connection. In this case, it's the p2p connection and yes, summarization will work this way.

    - Your first bullet is easy to understand, ospf can be enabled by using network command under the process or using the interface level command.

    Thank you very much Hari !!!

    Ciprian.

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