Considering RTF's BGP table in Example 11-36, RTF has picked the direct path via AS1 to reach 192.68.11.0/24 because it is shorter. The configuration in Example 11-37 shows how the AS_PATH information can be manipulated to make the AS_PATH longer by prepending AS numbers to the path. Considering the network illustrated earlier in Figure 11-6, Example 11-37 prepends two extra AS numbers to the AS_PATH information sent from RTC to RTA to change RTF's decision about reaching 192..
Updating the Routing Table in Active Mode with DUAL
Figure 3-6 shows feasible and advertised distance. Figure 3-6. Feasible and Advertised Distance—Active Mode When no alternative route is found in the routing table, the following actions are taken (using the network in Figure 3-6 as an example). The topology table of Router A starts with a path (successor) of A to D to G to X. The feasible distance is 20, and the advertised distance from Router D is 15. When Router D dies, Router A must find an alternative path to ..
Setting Payload Scrambling on an ATM Circuit
The command to enable scrambling varies depending on the type of circuit. For a T3 ATM circuit, you must use the command atm ds3-scramble, as follows: Router2#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router2(config)#interface ATM0/0 Router2(config-if)#atm ds3-scramble Router2(config-if)#exit Router2(config)#end Router2# For E3 circuits, scrambling is actually enabled by default, but you can disable it with the no form of the comm..
Special Rules Concerning Intra-area and Interarea Routes on ABRs
OSPF has a couple of rules concerning intra-area and interarea routes that take precedence over the simple comparison of the cost calculated for the various routes. The issue exists when more than one ABR connects to the same two areas. Many designs use two routers between the backbone and each nonbackbone area for redundancy, so this design occurs in many OSPF networks. The issue relates to the fact that with two or more ABRs, the ABRsthemselves, when calculating their own ..
Providing a Backup to Frame Relay Virtual Circuits
Using secondary connections to back up the main Frame Relay virtual circuits allows organizations to continue their business operations by ensuring network connectivity in the event of failures to the primary connections. Provisioning a secondary backup connection to the primary Frame Relay virtual circuit can prevent a single point of failure in the network. Some Frame Relay carriers offer network redundancy services by provisioning a secondary virtual circuit as a backup t..
