BGP

[rakeshvelagala]

Hi All,

We have a customer who formed BGP relationship with one of the ISP neighbor. The way they implemented is, they just form neighbor and they advertise only their subnet  but do not receive any from the ISP.

They just use static route to point to ISP.

Can anyone please advise, why there is a need to do this? (Any advantage)

Can't they just point to ISP using a static route without having to buy BGP AS?(If say saving Money)

Can they just get the routing table from ISP? 

I know that they are various thing we need to consider.

1)Can router handle the load?

2)Do they have dual links?

But other than this any specific advantage? Please advice.

Thanks

[Akash Agrawal · Accepted solution]

Hi,

Customer needs to have BGP session with ISP to advertise its internal network and its cutomer's networks to outside world. Else it needs to purchase ip pool from its ISP and ISP would do BGP origination and advertisement of that ip pool. Problem in this case is , when customer changes the service provider, he would need to re-assign ip addresses in his network given by new ISP. This is not easy and it is pain.

For outgoing traffic, if customer is having only one upstream link to ISP-1, no point of taking full routing table, insted it can have default route to push all traffic towards ISP-1. Now this default route can be taken via BGP from service-provider or static route. Customer must be redistributing static into IGP to make it available to other routers in the network.

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Regards,
Akash