Total Stuby Area between 2 ABRs

[mahesh18]

Hi all,

I tested the Totally Stuby Area between ABR  router and another router which connects to 2 Areas --  in short between 2 ABRs.

Router 1  ABR 1

i config

area 2 stub no-summary

Router 2 ABR2

area 2 stub

after this i did sh ip route on both Routers 1 and 2  and found that nothing changes.

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Then i made Router 2 as Single Area  after this i was able to see all OSPF routes gone from R2 and replaced by single default route.

So my question is Stub Area and totally stub area is not designed to work between 2 ABRs?

Thanks

MAhesh

[Reza Sharifi]

Mahesh,

R1-----area0----R2-----area1-------r3

r2 is ABR and is connected to area 0 and area 1. You deploy stub or stub no-summary on r2 and r3.  r2 will send a default route to r3 and r3 uses this default route to get to other areas.  Remember area 0 (backbone area) can not be configured as Stub or Stub no-summary or NSSA.

HTH

[mahesh18]

Hi Reza,

Thanks for reply.

I did not config area 0 as Stub .

R1 was ABR  between area 0 and 2

R2  was ABR  between Area  2 and 3.

I tried to config Totall stub area between these two.

But both routers R2 and R3 being ABR  thats why  Total stub area config does not work.

Mahesh

[Reza Sharifi · Accepted solution]

Hi Mahesh,

You can't configure stub are between 2 ABRs. Also, you can't connect area 2 directly to area 3.  You supposed to go through area 0 when connecting 2 none-0 areas together.  That is why area 0 is the transit area or backbone area.

HTH

[mahesh18]

Hi Reza,

I was doing Testing in My Home Lab to see how things go.

But now i tested and also came to know that Total stub Area does not work between 2 ABRs.

But i tested in my LAB Stub Area between 2 ABRs  and it did  filtered the E2 Routes to the Router 2  which was ABR.

and when i did sh  ip route on R2

O*IA 0.0.0.0/0 [110/2]   here E2 has been changed by O*IA.

So this shows that Stub Area can work between two ABRs but Total Stub Area does not right?

Thanks

MAhesh

[mahesh18]

Hi Reza,

Many thanks again for you reply.

Seems i have to learn lot from this Cisco Forum

Thanks

MAhesh