Help on BGP issue

[K.Prashant Rao]

Hi All,

 

Please see the attached wordpad document,

 

Thanks

--
Prashant K Rao

[K.Prashant Rao]

I took the topology from CCIE Theory  CBT Nuggets (Jeremy) BGP Part 4

--
Prashant K Rao

[Fahad Rahmani]

Hello.

I see you have followed good ip addressing scheme, but have missed at some places, this is what we follow in our network-effect.

network.network.lower_router_number-higher_router_number.Router_number.
So, this is what it would become if you connect R1-R2-R3, and the network is 192.168.x.x or 10.0.x.x.

192.168.12.1-192.168.12.2 R1-R2;  192.168.23.2-192.168.23.3 R2-R3
10.0.12.1 - 10.0.12.2 R1-R2; 10.0.23.2 - 10.0.23.3 R2-R3

I agree it will not work always, but as long as you have routers till 9 in number, it is very simple, we will post the complete scheme for MLS "int vlan" and other scenario - best ip addressing scheme.. this keeps things simple and will allow us to focus on issue rather then ip addressing scheme...
I hope that this makes sense.

You are trying to reach from R1 to R5.
R1 has route to the destination, using next hop as 10.12.1.2 -->
B    192.168.30.0/24 [200/0] via 10.12.1.2, 00:27:03
And by further lookup, you can find that 10.12.1.2 is reachable via s1/0

life is good so far.. let's move on to R2 and find out whether it has reachability to source and destination ip's...
B    192.168.30.0/24 [20/0] via 5.5.5.5, 00:27:33
D       5.5.5.5 [90/2297856] via 10.25.1.2, 00:42:56, Serial1/1

LIFE seems to be good... so far..

Let's move on to R5 and see whether it has the route to source & destination...

C    192.168.30.0/24 is directly connected, Loopback0 // So it is destination/source.

But we don't have any route to 10.12.1.2, why ?

Of course:
as 10.12.1.0 is being advertised only by EIGRP in ASXXXX, so what could be the solution...

1. default route on R5 pointing to R2.
2. default static route on R5 pointing to R2.
3. redistribute eigrp into BGP - very bad design, you will not do this usually in real world.. why would you redistribute you IGP into BGP and let world know about all your networks.
4. Redistribute EIGRP's selected route "distribute-list or any other mechanisim" - ok
5. Redistribute connected on R2 in BGP, that will tell R5 how to reach 10.12.1.0 network...

Here we have a classical scenario.. consider 10.12.1.0 not as link between R2-R1 but as server farm in your internal network, and indeed you would like the world to reach this ip... follow the above solutions and get it advertised to the world...

Do let me know the following:
1. did this resolved the issue.
2. Was response comprehendable.
3. Do you think we need to standardize on the format.
4. Anything else, which would help us, and make us more comprehendable.

Have a great day.
Regards.

On Wed, Apr 15, 2009 at 8:33 AM, K.Prashant Rao <per...@gmail.com> wrote:

[K.Prashant Rao]

Thanks a lot for the explanation Fahad Bhai.

 

Yes, I too was thinking about the first two options

 

1. default route on R5 pointing to R2.
2. default static route on R5 pointing to R2.

 

I would imagine, the solution you mentioned are in the order of most appropriate and preferred way (top to bottom)   -- right ?

 

Regarding the IP addressing scheme - I will start to follow our standard conevention as explained by you, from now on.

 

My responses:-

 

1. did this resolved the issue. --  YES.
2. Was response comprehendable. --  YES.
3. Do you think we need to standardize on the format.  -- Yes, we could come up with something like a template, which if logically designed, would let us enter our problem and steps taken in a more organized format.

4. Anything else, which would help us, and make us more comprehendable. -- Yes, more of some tips / suggestions like the IP addressing scheme that you just mentioned, will help us put our doubts across in a standard and more structured way and naturally, the responses from whoever is providing the solution will also be better.

 Thank you

Peru

--
Prashant K Rao