Configuration Guide User guide

814 BigIron RX Series Configuration Guide

53-1002484-04

Overview of BGP4

•Using the IP default route as a valid next hop for a BGP4 route . . . . . . . . 858

•Enabling next-hop recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858

•Modifying redistribution parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861

•Using a table map to set the tag value . . . . . . . . . . . . . . . . . . . . . . . . . . . . 864

•Changing the keep alive time and hold time . . . . . . . . . . . . . . . . . . . . . . . . 865

•Changing the BGP4 next-hop update timer . . . . . . . . . . . . . . . . . . . . . . . . . 865

•Changing the router ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865

•Adding a loopback interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 866

•Changing the maximum number of paths for BGP4 load sharing . . . . . . . 867

•Configuring route reflection parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 867

•Filtering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 870

•Displaying BGP4 information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900

•Generalized TTL security mechanism support . . . . . . . . . . . . . . . . . . . . . . 931

Overview of BGP4

BGP4 is the standard Exterior Gateway Protocol (EGP) used on the Internet to route traffic between

Autonomous Systems (AS) and to maintain loop-free routing. An autonomous system is a collection

of networks that share the same routing and administration characteristics. For example, a

corporate Intranet consisting of several networks under common administrative control might be

considered an AS. The networks in an AS can but do not need to run the same routing protocol to

be in the same AS, nor do they need to be geographically close.

Routers within an AS can use different Interior Gateway Protocols (IGPs) such as RIP and OSPF to

communicate with one another. However, for routers in different ASs to communicate, they need to

use an EGP. BGP4 is the standard EGP used by Internet routers and therefore is the EGP

implemented on the device.