EIGRP uses three tables: the neighbor table, the topology table, and the IP routing table. The neighbor table keeps state information regarding neighbors, and is displayed using the show ip eigrp neighbors command. EIGRP Update messages fill the routers’ EIGRP topology tables. Based on the contents of the topology table, each router chooses its best routes and installs these routes in its respective IP routing table. An EIGRP router calculates the metric for each route bas..
EIGRP Reliable Transport Protocol
Five types of EIGRP packets exist, further categorized as reliable packets and unreliable packets. The reliable EIGRP packets are as follows: • Update— Update packets contain EIGRP routing updates sent to an EIGRP neighbor. • Query— Queries are sent to neighbors when a route is not available and the router needs to ask the status of the route for fast convergence. • Reply— Reply packets to the queries contain the status of the route being queried..
RSVP-DiffServ integration provides a translation between RSVP and DiffServ technologies that is intended to leverage the strengths of each model. RSVP is used for bandwidth reservation at the edge of the network (where there are fewer flows and the most bandwidth constraints), but DiffServ is used over the backbone network so that the backbone routers do not have to keep per-flow states. This topology is shown in Figure 8-4. Figure 8-4. RSVP-DiffServ Integration [View full s..
Mitigating the Detrimental Effects of the BGP Restart
To sum up the earlier discussion, BGP restart causes route flaps, which can lead to transient black holes and increased consumption of link bandwidth and control processor resources. Thus route flaps can degrade the overall network performance. The source of route flaps can be traced back to the BGP restart behaviorspecifically, deletion of routes derived from the failed session. As mentioned previously, peers withdraw routes from a restarting speaker to find alternative pat..
By default, a Catalyst switch detects an error condition on every switch port for every possible cause. If an error condition is detected, the switch port is put into the errdisable state and is disabled. You can tune this behavior on a global basis so that only certain causes trigger any port being disabled. Use the following command in global configuration mode, where the no keyword is added to disable the specified cause: Switch(config)# [no] errdisable detect cause ..
