Filtering Subnets of a Summary Using the aggregate-address Command
Manual BGP route summarization, using the aggregate-address BGP router subcommand, provides the flexibility to allow none, all, or a subset of the summary’s component subnets to be advertised out of the BGP table. By allowing some and not others, the aggregate-address command can in effect filter some routes. The filtering options on the aggregate-address command are as follows: ■ Filtering all component subnets of the summary from being advertised, by using the summary-..
When the boot field is not a hex 0 or 1, routers choose the OS through the use of the boot system configuration command. If the configuration register calls for a full-featured IOS (boot field 0x2-F), the router reads the startup-configuration file for boot system commands. If present, the router tries each boot system command, in succession, until it finds an IOS to load. If there are no boot system commands, the router takes the default action, which is to load the first fi..
WFQ Drop Policy, Number of Queues, and Queue Lengths
WFQ uses a two-step process called modified tail drop to choose when to drop packets. First, WFQ considers the absolute limit on the number of packets enqueued among all queues; this limit is called the hold-queue limit. If a new packet arrives, and the hold-queue limit has been reached, the packet is discarded. That part of the decision is based not on a single queue, but on the whole WFQ queuing system for the interface. Second, WFQ considers the length of the queue into w..
Enhanced IGRP and Bandwidth Control
Before continuing with Enhanced IGRP and bandwidth-related commands, you should understand bandwidth control. By default, Enhanced IGRP limits itself to 50 percent of the configured bandwidth. A benefit of controlling Enhanced IGRP usage is that it limits the Enhanced IGRP traffic in case of failure. This makes the rest of the bandwidth available for data traffic. Another advantage is that you avoid losing Enhanced IGRP packets, which could occur when Enhanced IGRP generates ..
To enable locally administered user IDs, use the following set of configuration commands: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#username ijbrown password oreilly Router1(config)#username kdooley password cookbook Router1(config)#aaa new-model Router1(config)#aaa authentication login local_auth local Router1(config)#line vty 0 4 Router1(config-line)#login authentication local_auth Router1(config-line)#exi..
