Benifits of BGP

[er.satishkm]

A company's network is spread over six locations.six different-2 cities.Headqurter is situated in Sydney and branch offices are located in the other cities.on the headquarters office OSPF network is running and branch offices are running bgp networks.so i have a question why they use bgp.and what are the banifits to use BGP on the branch (Clients) offices.plz explain.?

[Jon Marshall]

Satish

Difficult to say without the information provided.

Generallys speaking BGP is used when you have multiple entry and exit points to and from your network (your network being your LANs and WANs). It allows you to influence both inbound and outbound traffic.

If you only have one exit and entry point from your network then there is little benefit to be gained from BGP. Having said that the one area where you may find BGP being used even when there is only one exit/entry point is if you are running an MPLS network. Some providers will only allow you to use BGP as the dynamic routing protocol to peer with their MPLS cloud.

Jon

[ameya_oke]

Hi Satish,

BGP is an industry darling because of the kind of customization power is provides.

There are more than 13 attributes that can be tweaked and twised to infulence the incoming and outgoing traffic.

Also the branch offices which required high redundancy(Dual WAn links with 2 different ISPs), you would have BGP running, not on all branch offices and certainly not where you have only 1 WAN link.

Generally an office which demands 24*7*365 operations, a high redundancy protocol is required and BGP is certainly best at that.

BGP due to its slow convergence is an asset for a large cloud and it is due to this feature it is most suited for internet.

There are many more advantages of BGP, i am sure you would find many docs on CSC.

please rate if helps

Ameya

[Mohamed Sobair]

Satish,

There are multiple factors to use BGP. As the name implies , BGP is a Boarder Gateway Protocol (Path Vector Protocol) that is commonly used to connect different Autonomous Systems, basically connects two or more different Companies/Authorities.

However, In some occations, you would also prefer to run BGP inside your Networks between your Edge routers withing the AS.

Themain reason for this approach is that when you run IBGP between your AS boarder routers , You maintain BGP attributes along the Path. If you are running OSPF/EIGRP within your Network and BGP as well and perform redistribution between both, you have simply negate or dis-maintaining the Attributes of BGP which would be lost once redistribution Occurs.

Another reason would be Some Service Providers prefer to run BGP as thier main routing protocol with the customers, especifically between PE - CE routers, because it provides better Administrative Overhead and Control.

Besides all of that, when BGP initially was designed, it was because it eleminate the affect of instability between The Local IGPs and BGP in such away to prevent instability of Interior Gateway Protocols to have an effect on the External BGP links , thats one of the reasons to have an External routing Protocol to connect different ASs.

Your answer could be one of the above, and its all depend on the design requirment to use Particularly BGP in the branches, as they could have External clients require that, Or required by the Provider, or They could have a Network needs to maintain BGP attributes along the path expecifically when connecting Boarder Edge routers.

HTH

Mohamed