BGP - redistribute connected

Unanswered Question
Jan 30th, 2009

Hello,

Is there any downside to using redistribute connected in a full mesh BGP environment, when OSPF is used as the IGP?

Reason I need to use redistribute connected is because of the few hundred VLAN interfaces I have on my 6500s, and did not want to put individual network statements for them all of course.

I just wanted to see if anyone has experienced problems with doing that, since it will put your point to point links and loopbacks into the BGP table, and those networks are the only networks in my OSPF table, for next hop reachability.

Thanks for any input.

I have this problem too.
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Giuseppe Larosa Fri, 01/30/2009 - 13:25

Hello Jason,

be aware that iBGP will propagate updates there are not going to be used for their higher AD (200) in comparison to OSPF (110) = to be not installed in the routing table.

I would decide to use a route filter and to redistribute in BGP ip subnets that represent services / clients and would keep in OSPF all the infrastructure links and loopbacks.

In this way you can minimize OSPF database and make effective usage of iBGP as a way to provide scalability.

This is common practice in service provider environments or big entreprise.

Hope to help

Giuseppe

Jasonch518_2 Sun, 02/01/2009 - 10:43

Thanks for the input from both of you.  I think I will go with the filter to deny the routes that I do not want to have in my BGP table, since they will already be in OSPF, aka the infrastructure links.

 

Jason.

 

celiocarreto Sun, 02/01/2009 - 09:37

Hi,

I would use summary-routes and put them into IGP via

ip route x.x.x.x y.y.y.y Null 0

in BGP now only few of network satements can be used.

Regards, Celio

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