Any router in active state for a route must wait for a Reply to each of its Query messages. It is possible for a router to wait several minutes for all the replies, because neighboring routers might also need to go active, and then their neighbors might need to go active, and so on—each withholding its Reply message until it in turn receives all of its Reply messages. In normal operation, the process should complete; to handle exception cases, EIGRP includes a timer called ..
Forming PIM Adjacencies Using PIM Hello Messages
PIM routers form adjacencies with neighboring PIM routers for the same general reasons, and with the same general mechanisms, as many other routing protocols. PIMv2, the current version of PIM, sends Hello messages every 30 seconds (default) on every interface on which PIM is configured. By receiving Hellos on the same interface, routers discover neighbors, establish adjacency, and maintain adjacency. PIMv2 Hellos use IP protocol number 103 and reserved multicast destination ..
The previous section described the technical definition of a VLAN. This section describes practical answers. In a legacy network, administrators assign users to networks based on geography. The administrator attaches the user's workstation to the nearest network cable. If the user belongs to the engineering department and sits next to someone from the accounting department, they both belong to the same network because they attach to the same cable. This creates some interesti..
Configuring Supervisor Synchronization
By default, the active supervisor synchronizes its startup configuration and configuration register values with the standby supervisor. You also can specify other information that should be synchronized. First, use the following commands to enter the main-cpu configuration mode: Router(config)# redundancy Router(config-red)# main-cpu Then use the following command to specify the information that will be synchronized: Router(config-r-mc)# auto-sync {startup-config | config-reg..
Redistributing Static Routes into RIP
The biggest potential problem that you will encounter with redistributing routes into RIPv1 comes from breaking network class boundaries. This version of RIP is classful, so you have to be rather careful about how you distribute routing information from other sources that may be classless. In the example in this recipe, Router1 redistributes a static route for the Class C network 192.168.10.0. But if we tried instead to redistribute a larger range, such as 192.168.12.0/22, RI..
