BGP Query

[gaurav_saxena]

We have Internet peering with multiple ISPs at Asia Pacific, Europe, US, UK , Honkong. From these Internet peerings, we are receiving all the internet routes. Is there any way we can filter prefixes based on geography.How we can find out what prefix belongs to which specified geography?

[mchin345]

The BGP Prefix-Based Outbound Route Filtering feature uses Border Gateway Protocol (BGP) outbound route filter (ORF) send and receive capabilities to minimize the number of BGP updates that are sent between BGP peers. Configuring this feature can help reduce the amount of system resources required for generating and processing routing updates by filtering out unwanted routing updates at the source. For example, this feature can be used to reduce the amount of processing required on a router that is not accepting full routes from a service provider network.

More information : http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t4/ftbgporf.htm#wp1027129

[marikakis]

I have never heard of a way to filter prefixes based on geography.

Why would you want to do this ?

To save some router resources or

to influence your outgoing traffic so that circles around the globe are avoided ?

(e.g. traffic for a US destination doesn't exit from you Asia exit point)

M.