BigIron RX Series Configuration Guide xxiii53-1002253-01Chapter 26 Configuring BGP4 (IPv4 and IPv6)Overview of BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .739Relationship between the BGP4 route table and the IP routetable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740How BGP4 selects a path for a route . . . . . . . . . . . . . . . . . . . . 740BGP4 message types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 742Brocade implementation of BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . 744Memory considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744Configuring BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745When parameter changes take effect . . . . . . . . . . . . . . . . . . . 749Activating and disabling BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .750Note regarding disabling BGP4. . . . . . . . . . . . . . . . . . . . . . . . .750Entering and exiting the address family configuration level . . . . .751Filtering specific IP addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . .751Defining an AS-path filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .753Defining a community filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .753Configuring a switch to allow routes with its own AS number . . . .754BGP Null0 routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .755Aggregating routes advertised to BGP4 neighbors. . . . . . . . . . . . .759Configuring the device to always compare MEDs . . . . . . . . . . . . . .759Disabling or re-enabling comparison of the AS-path length . .760Redistributing IBGP routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .760Disabling or re-enabling client-to-client route reflection. . . . . . . . . 761Configuring a route reflector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761Enabling or disabling comparison of the router IDs . . . . . . . . . . . . 761Configuring confederations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .762Configuring route flap dampening . . . . . . . . . . . . . . . . . . . . . . . . . .765Originating the default route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .765Changing the default local preference . . . . . . . . . . . . . . . . . . . . . .766Changing the default metric used for redistribution. . . . . . . . . . . .766Changing administrative distances . . . . . . . . . . . . . . . . . . . . . . . . .767Requiring the first AS to be the neighbor’s AS . . . . . . . . . . . . . . . .768Neighbor local-AS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .768Enabling fast external fallover . . . . . . . . . . . . . . . . . . . . . . . . . . . . .768Setting the local AS number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .769Changing the maximum number of shared BGP4 paths . . . . . . . .769Treating missing MEDs as the worst MEDs. . . . . . . . . . . . . . . . . . .770Customizing BGP4 load sharing. . . . . . . . . . . . . . . . . . . . . . . . . . . .770
