Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Stub area and totally stub area and default route 0.0.0.0/0 and other conce

Cisco curriculum CCNP1 V3.0 Article 6.7.1 says:

((A stub area does not accept information about routes external to the AS. the ABR on the stub automatically propagates a 0.0.0.0/0 default route within the area)).

(( A totally stubby area is a stub area that blocks external Type 5 LSAs and summary (Type 3 and Type 4) LSAs from entering the area.

This way, intra-area routes and the default of 0.0.0.0/0 are the only routes known to the stub area.,,,,,,,should not it say “ to the totally stub area” instead of “to the stub area” ?

ABRs inject the default summary link 0.0.0.0/0 into the totally stubby area)).

1- Both area (stub and totally stub) have got type 1 and type 2

2- Stub area has got type 3 only, whiles totally stub has not got that .

3- Both of them have got default route 0.0.0.0/0.

4- Now we can conclude that the difference between the stub and totally stub is only type 3,,,Am I right ?

5- Does the default route for stub area is of type 3 (why I am saying that see below) ? If so,,that means there is no difference between stub and totally stub!!! Any explanation

6- And suppose the default route is of type 3,,,what does that mean ?

If you look to the second figure in the link below

http://www.cisco.com/warp/public/104/21.html

It shows me that the default route that will be injected in Stub area and totally stubby area is type 3,,,,,,,,Is this typo ? because it looks different form what the Cisco curriculum states,,,,,,,Any comment ?

In another document (Internet work Expert Lab)

“A stub area blocks OSPF external routes (LSA 5) form entering the area. The ABR of a stub area automatically generates a default route (LSA 3) into the stub area “.

  • Other Network Infrastructure Subjects
2 REPLIES
Bronze

Re: Stub area and totally stub area and default route 0.0.0.0/0

Hello,

-->This way, intra-area routes and the default of 0.0.0.0/0 are the only routes known to the stub area.,,,,,,,should not it say “ to the totally stub area” instead of “to the stub area” ? <--

The totally stubby area would only have the default (type 3) route, while the stub area would have the inter-area routes AND the default route. So I think the statement above should read ´This way, inter-area routes and the default of 0.0.0.0/0 are the only routes known to the stub area.,,,,,,,should not it say “ to the totally stub area” instead of “to the stub area” ?

Also, the default route injected in both stub and totally stub areas is a type 3, where in the curriculum does it say something else ?

The difference between stub and totally stub is that the totally stubby area would not allow type 3 & 4 inter-area routes (which the stubby area does allow), and instead only generate a default type 3.

Does that make sense ? It can be somewhat tedious to get the concept...

Regards,

Nethelper

New Member

Re: Stub area and totally stub area and default route 0.0.0.0/0

You are saying : ((The totally stubby area would only have the default (type 3) route, while the stub area would have the inter-area routes AND the default route.)),,,

That is fine

((So I think the statement above should read ´This way, inter-area routes and the default of 0.0.0.0/0 are the only routes known to the stub area))

Correct me if I am wrongor

A-

"1-Intra-area (Type 1 and Type 2)

2- Inter-area (Type 3 only not type 4)

3- Default of type 3 (I did not say type 0.0.0.0/0 because I think you consider it a typo? ) are the only routes known to the stub area".

alternatively :

B-

"1-Intra-area routes (Type 1 and Type 2)

2- No inter-area routes

3- Default of type 3 are the only routes known to the totally stubby area".

((where in the curriculum does it say something else ? ))

Shall I consider that there is typo in Cisco curriculum ?

((The difference between stub and totally stub is that the totally stubby area would not allow type 3 & 4 inter-area routes {which the stubby area does allow}, and instead only generate a default type 3.

))

1- Yes that is fine with totally stubby area it does not allow inter-area (type 3 and type 4).

2- But with stub area it does allowe inter-area type 3 only not type 4 (It does not allow type 4).

3- The reason I am saying that, that one guy in this forum has prooved that for me form RFC

142
Views
0
Helpful
2
Replies
This widget could not be displayed.