Border Gateway Protocol (BGP) is the back bone protocol that connects the internet. It falls under the External Gateway Protocols (EGP), interestingly it is the only routing protocols used in the external networks.
BGP is a robust protocol that can handle 100k routes, which are increasing. That as for IPv4 addresses, IPv6 addresses will have even more routes!
Manipulation of routes within the BGP cloud is one of the most challenging tasks a network engineer will be given. To manipulate the routes various Path Attributes (PAs) can be changed. They are done mainly by using:
- neighbor distribute-list (standard ACL / extended ACL)
- neighbor prefix-list
- neighbor filter-list
- neighbor route-map