OSPF or IBGP?

[forsudhaji]

Dear Friends,

I have a small query....Whats the difference between using OSPF as IGP and using IBGP.

Say I am an ISP and have POP's in multiple locations..What is the difference between the 2 options below:

a) Bringing all core BB routers under Area 0

b) running IBGP with them..

Pls let me know..

Sudha.

[Georg Pauwen]

Hello,

if you are running OSPF as your IGP, you only need BGP on your edge routers. If you run only BGP without an IGP, you will need to configure static routes between your BGP peers, which will obviously conserve memory. What are you trying to achieve ? Is this a lab/test scenario, or a real-life situation ? In the latter case, you will need BGP anyway, in order to exchange information with other ISPs, and most likely also with your customers.

Regards,

GP

[forsudhaji]

Thanx for ur reply...I will explain u my full realtime scenario...

Assume we have POP in many locations say a,b,c,d,..up to h ; b and d being the locations where we have internet gateways..Routers within all locations runs IGP with different areas..They have no common area among them (as are 0)..But they use IBGP between locations to distribute routes of one location to others.

In this scennario..I want to know whether using Area0 is advantage or using IBGP??

What is the adv/disadv of both??

Pls let me know..

Sudha.

[forsudhaji]

Thanx for ur reply...I will explain u my full realtime scenario...

Assume we have POP in many locations say a,b,c,d,..up to h ; b and d being the locations where we have internet gateways..Routers within all locations runs IGP with different areas..They have no common area among them (as are 0)..But they use IBGP between locations to distribute routes of one location to others.

In this scennario..I want to know whether using Area0 is advantage or using IBGP??

What is the adv/disadv of both??

Pls let me know..

Sudha.

[spremkumar]

Hi

OSPF is basically designed with 1 backbone area and mutiple stub/NSSA/TSA.Backbone Area can contain few hundred routers also the other areas.This will be ok within an organisation point of view.

But this wont be the same in the case of IBGP which is more resource extensive as mentioned by the previous post.

BTW You can run OSPF in ur backbone with IBGP carryiing only the external routes(defaults) to your peers,so in case of any G/W failure at your end still you would be getting defaults from u r ibgp peer.

regds

prem