Link-state routing protocols, such as Open Shortest Path First (OSPF)[] and Intermediate System-to-Intermediate System (IS-IS)[], utilize a replicated distributed database model and are considered to be more-complex routing protocols. Link-state protocols work on the basis that routers exchange information elements, called link states, which carry information about links and nodes in the routing domain. This means that routers running link-state protocols do not exchange rout..
Cisco IOS processes the Access Control Entries (ACEs) of an ACL sequentially, either permitting or denying a packet based on the first ACE matched by that packet in the ACL. For an individual ACE, all the configured values must match before the ACE is considered a match. Table 21-8 lists several examples of named IP ACL permit and denies commands that create an individual ACE, along with their meanings. Table 21-8 Examples of ACL ACE Logic and Syntax The Port Number f..
The Level 2 capable routers in Figure 7-13 contain all the specific routes in their IP routing tables. For example, Router E has 18 specific routes in Example 7-18. Example 7-18. IS-IS Routes in the IP Routing Table of Router E E#show ip route | include L2 i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area i L2 156.26.2.0 [115/31] via 172.16.15.161, Serial0/0 i L2 156.26.3.0 [11..
The ip summary-address eigrp configuration command allows you to configure manual summary addresses on a per-interface basis: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#interface Serial0/0.2 Router1(config-subif)#ip summary-address eigrp 55 172.25.0.0 255.255.0.0 Router1(config-subif)#exit Router1(config)#end Router1# EIGRP can automatically summarize subnet routes into classful network-level routes. You c..
Introduction to the Cisco Frame Relay Implementation
Cisco's Frame Relay implementation supports the basic Frame Relay protocol and conforms with the local management interface (LMI) specifications originally developed by the consortium of Cisco Systems, StrataCom, Northern Telecom, and Digital Equipment Corporation (DEC). This consortium of the four companies is popularly known as the "Gang of Four." One of the main objectives of the collaboration by the Gang of Four was to enhance the interoperability of future Frame Relay pr..
