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New Member

EIGRP;OSPF;BGP

Hi Experts!

i have to know why most ISPs Run EIGRP;OSPF;BGP ON THEIR Network?i know BGP IS Important For external AS.WHY they not use only routing protocol either OSPF or EIGRP not both of Them WITH BGP for external AS...

i truly appreciate ur reply...

7 REPLIES

Re: EIGRP;OSPF;BGP

BGP is exterior routing protocol which means it run between different autonomous systems. for e.g between customer and ISPs or between ISPs.

EIGRP, OSPF are interior gateway routing protocols which will run wihin a autonomous system (AS). So, you will always prefer to run a single interior routing protocol i.e EIGRP/OSPF/IGRP/RIP within you network.

If your network have multiple interior routing protocol, then you need to configure re-distribution between routing protocols.

In BGP, again there is iBGP (interior BGP) which will run within AS and eBGP (Exterior BGP) which will run between different AS.

hope it help ... rate if it does ...

Re: EIGRP;OSPF;BGP

Hi ,

Routing protocols like OSPF , Eigrp are designed as IGP to be run within an AS considering the convergence , number of routes that would be in the IGP to handle and route flapping . IGP's can handle route flapping within an AS and would be fine .

BGP is EGP designed to handle large number of routes and convergence is not a problem among multiple AS rather than considering Convergence within an AS .

Using BGP within an AS would be an added advantage to IGP .

Hope this helps

regards

vanesh k

New Member

Re: EIGRP;OSPF;BGP

Hi appreciate all ur replys

Re: EIGRP;OSPF;BGP

In Addition to the above posts, BGP is most versatile protocol when it comes to enforcing policies.

With BGP you can have traffic control to a certain set of AS and this is very important from an ISP point of view.

Also there are more than 1,50,000 routes on the internet and no IGP can support that amny routes.

HTH

Narayan

New Member

Re: EIGRP;OSPF;BGP

Hi Narayan;10xs for ur reply!!!

New Member

Re: EIGRP;OSPF;BGP

OSPF is nice because it is a smart protocol for maintaining your Routing table as compared to manually entering and updating your network information in RIP to keep the Table update.

Hope this helps

New Member

Re: EIGRP;OSPF;BGP

EIGRP is a Cisco protocol that is only supported on Cisco routers. Most ISP's have multi-vendor networks and use OSPF or IS-IS because they are standards based protocols which can be used between differenet vendor's routers. BGP is used to talk between service provider and customer.

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