Identifying Neighbors and Defining Peer Groups

BGP does not promiscuously attach to other routers—neighbors must be predefined. The neighbor command is used to identify each neighbor and its AS. If the neighbor AS is the same as this router's AS then this is an iBGP connection. If the AS is different, this is an external neighbor. After the neighbor is defined, further neighbor commands are used to describe the policy used to filter routes to the neighbor.  Router(config-router)#neighbor ip-address remote-as auto..

Maintaining the Topology Table

The topology table may be recalculated because a new network is added to the network, successors change, or because a network is lost. Figure 3-4 illustrates the traffic flow seen when a router loses a connection.  Figure 3-4. Traffic Flow Used to Maintain the Topology Table Just as the neighbor table tracks the receipt of the EIGRP packets, the topology table records the packets that have been sent by the router to the neighbors. It also identifies the status of the ..

Populating the FIBs

IP prefixes from each routing process are inserted in the central forwarding information base (FIB). This is the routing table used for actual packet forwarding. When there are two equal-length prefixes from the different RIBs or different routing processes or protocols, an administrative distance is applied to break the tie. This distance typically is applied to the whole routing process—with the notable exception being BGP, which has different administrative distances for..

Using an Internal ISDN PRI Module

You can configure an ISDN PRI controller module by using the controller T1 command set as follows: Router8#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router8(config)#isdn switch-type primary-dms100 Router8(config)#controller T1 0 Router8(config-controlle)#framing esf Router8(config-controlle)#clock source line primary Router8(config-controlle)#linecode b8zs Router8(config-controlle)#pri-group timeslots 1-24 Router8(config-controlle)..

Reverse-Tunnel Forwarding

You configure Reverse-Tunnel Forwarding on the Mobile Node so that it requests this feature when it registers with the Foreign Node: RouterMobile#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. RouterMobile(config)#ip mobile router RouterMobile(mobile-router)#reverse-tunnel RouterMobile(mobile-router)#exit RouterMobile(config)#end RouterMobile# When a Mobile Node communicates with another device elsewhere on the network (called th..