BGP Help Please !!!

[volv]

Does anyone out there know how to help me with the following scenario ?

Consider this... 2 adjacent routers (lets say R1 & R2) peered via loopbacks are within an (AS) consisting of 5 other BGP speaking routers, You are asked the following.

1)Set up an ospf peering between the connecting serial interfaces, and place a newly created loopback on R1 into OSPF also.

2)Have this new loopback advertised into the entire BGP AS so that all of the other BGP speakers have both the OSPF peered address range, and the new loopback on R1 int their BGP tables, without the use of the "network" statement or by "redistribution" ?????

thanks

 

[SnowNinja]

What area of study is this question from?

-SnowNinja

 

[volv]

This is a CCIE study example and any help would be appreciated

 

[andreyts]

neighbor x.x.x.x remote-as yyy
neighbor x.x.x.x update-source loopback 0

I am think this is the way to connect between them.

Best Regards,

Andrey
CCNA

 

[volv]

Based on my understanding, this command is used to establish peering relationships between the neighbor and the local router's loopback address (when using "update-source loopback 0") and the reverse configuration has to be implemented on the remote router for proper peering to be established... I did try your suggestion, but, was unable to get the desired result,if your configuration is done in a different way, i would be very interested in the outcome.

 

[lambent]

under "router bgp", use "aggregate-address" to advertise if it said that you cannot use "network" or "redistribution" command.

 

[volv]

Hi Lambert, do you have to do anything clever with the aggregate-mask to get this working, as both of the required networks are /24 that was all i used for this (aggregate-mask) however still with no joy.

 

[lambent]

All I know is that once your IGP installs routes in your routing table, you can use the bgp command "aggregate-address" to advertise the prefixes with options like summary-only.

If the question doesn't ask you to suppress more specific prefixes, that means you can ignore the summary-only option so those more specific prefixes will also be advertised together with the summary route.

Say if you have 2 prefixes:

192.168.1.0/24
192.168.2.0/24

If you want to "advertise" these 2 prefixes without using "network" or "redistribute" commands, then you need to do this:

!
router bgp 65000
aggregate-address 192.168.0.0 255.255.0.0
!

This will advertise the prefix 192.168.0.0/16, together with the more specific prefixes 192.168.1.0/24 and 192.168.2.0/24.

Also make sure you have either a full-mesh iBGP sessions between neighbors or use route reflectors.