Changing the Router from Level 1-2
By default, routers support both Level 1 and Level 2 routing. Routing at both levels means twice as many hellos and advertisements, twice as much memory consumed, and twice as much processing. However, routing at both levels makes configuration easier. One easy way to optimize IS-IS is to reduce the unnecessary duplication of routing at both levels. IS-IS level is set under the IS-IS process using the is-type level-1 or is-type level-2 commands. Once applied, all interfaces c..
Level 1 router summarization is done only for external routes (redistributed routes from other protocols) because the level 1 router does not receive any routes from the level 2 routers. As such, there is no need to summarize routes from level 2 routers—you can summarize both level 1 and external routes in level 2. External routes can be summarized only at the redistributing router. After the LSP is originated, it cannot be summarized. Summarizing of external ..
Traffic-Shaping Adaptation on Frame Relay Networks
A shaper used with Frame Relay can be configured to vary the shaping rate over time based on the presence or absence of congestion. When there is no congestion, the shaper uses the shaping rate,but when congestion occurs, it lowers the shaping rate, eventually reaching a minimum shaping rate. The minimum rate can be configured, or default to 50 percent of the shaping rate. This lower rate is typically called either the minimum information rate (MIR) or the mincir. To lower t..
Certain traffic types, such as Layer 2 keepalives and Layer 3 routing protocol messages, are absolutely critical to maintaining network stability. Therefore, it is vital to understand how the Cisco IOS Software handles these traffic types, especially when provisioning WAN links that might experience sustained periods of congestion. By default, Cisco IOS Software (in accordance with RFC 791 and RFC 2474) marks Interior Gateway Protocol (IGP) traffic (such as Routing Informati..
You can configure the router to log the total number of TCP sessions, rather than just the number of packets, with the following set of commands: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z.Router1(config)#access-list 122 permit tcp any any eq telnet establishedRouter1(config)#access-list 122 permit tcp any any eq telnetRouter1(config)#access-list 122 permit ip any anyRouter1(config)#interface Serial0/0Router1(config-if)#ip ac..
