Avoiding Routing Loops When Redistributing

Routing loops occur when a routing protocol redistributes routes into another protocol and then receives the same routes back—a process called route feedback. Because the metric is reset through redistribution, the routing protocol could see the redistributed path as more attractive. The potential for confusion is enormous, as shown in Figure 11-3; routes distributed from OSPF to EIGRP are distributed back to EIGRP at two redistribution points, causing the routing tables of..

Configuring Bandwidth over a Multipoint Network

In addition to being used in the EIGRP metric, the bandwidth command influences how EIGRP uses NBMA virtual circuits (VCs). If the serial line has many VCs in a multipoint configuration, EIGRP will assume that each VC has an even share of bandwidth. EIGRP will confine itself to using half that share for its traffic. This limitation is important—no other routing protocol does this—but will work best if the bandwidth is correctly defined. A 56-kbps link that has a bandwidth..

DoS/Worm-Mitigation Strategies

A proactive approach to mitigating DoS/worm flooding attacks within campus environments is to respond immediately to out-of-profile network behavior that indicates a DoS or worm attack using access-layer policers. Such policers could meter traffic rates received from endpoint devices, and when these exceed specified watermarks (at which point they no longer are considered normal flows), these policers could mark down excess traffic. In this respect, the policers would be fai..

Configuring Cisco IOS MLP LFI for Frame Relay on a Cisco Router

This section describes the configuration tasks involved in setting up the LFI feature for Frame Relay virtual circuits on a Cisco router. Note that the Cisco IOS software supports LFI via MLP, LFI via MLP over Frame Relay, and LFI via MLP over ATM. In this section, only the configuration tasks concerning LFI via MLP over Frame Relay virtual circuits are discussed. NOTE The Cisco IOS MLP LFI feature for Frame Relay and ATM virtual circuits is released in Cisco IOS Release 12..

Setting Up Frame Relay with Point-to-Point Subinterfaces

Probably the cleanest way to set up a Frame Relay network is to use point-to-point subinterfaces. If you have a host site that connects to two or more branches through a Frame Relay WAN, you could configure the central host router like this: Central#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Central(config)#interface Serial0 Central(config-if)#description Frame-Relay host circuit Central(config-if)#no ip address Central(config-if)#e..