BigIron RX Series Configuration Guide xxiii53-1001810-01Overview of BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .738Relationship between the BGP4 route table and the IP route table739How BGP4 selects a path for a route . . . . . . . . . . . . . . . . . . . . 740BGP4 message types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741Brocade implementation of BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . 743Memory considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744Configuring BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744When parameter changes take effect . . . . . . . . . . . . . . . . . . . 746Activating and disabling BGP4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 748Note regarding disabling BGP4. . . . . . . . . . . . . . . . . . . . . . . . . 748Entering and exiting the address family configuration level . . . . . 749Filtering specific IP addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749Defining an AS-path filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .751Defining a community filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .751Configuring a switch to allow routes with its own AS number . . . .752BGP Null0 routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .753Aggregating routes advertised to BGP4 neighbors. . . . . . . . . . . . .757Configuring the BigIron RX to always compare Multi-Exit Discriminators(MEDs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .757Disabling or re-enabling comparison of the AS-path length . .758Redistributing IBGP routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .758Disabling or re-enabling client-to-client route reflection. . . . . . . . .759Configuring a route reflector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .759Enabling or disabling comparison of the router IDs . . . . . . . . . . . .759Configuring confederations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .760Configuring route flap dampening . . . . . . . . . . . . . . . . . . . . . . . . . .763Originating the default route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .764Changing the default local preference . . . . . . . . . . . . . . . . . . . . . .764Changing the default metric used for redistribution. . . . . . . . . . . .765Changing administrative distances . . . . . . . . . . . . . . . . . . . . . . . . .765Requiring the first AS to be the neighbor’s AS . . . . . . . . . . . . . . . .766Neighbor local-AS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .766Enabling fast external fallover . . . . . . . . . . . . . . . . . . . . . . . . . . . . .767Setting the local AS number. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .767Changing the maximum number of shared BGP4 paths . . . . . . . .768Treating missing MEDs as the worst MEDs. . . . . . . . . . . . . . . . . . .768Customizing BGP4 load sharing. . . . . . . . . . . . . . . . . . . . . . . . . . . .769
