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..
The operation of RSVP is shown in Figure 14-12. Because the routed path from sender to receiver may be asymmetric, such as when the path for traffic from Host A to Host B is via R1, R2, R3, and the return path is via R3, R1, senders must prime the routers to expect reservation requests for a particular flow. This is accomplished by using path messages from the sender to the first hop router toward the receiver. The first hop router inserts its own address as the..
This section presents a sample network to summarize the configuration for MPCs and MPSs. Figure 10-9 Sample MPOA Network illustrates the network where two MPCs interconnect through one MPS. Figure 10-9. Sample MPOA Network The MPCs reside inside of Catalysts equipped with MPOA-capable LANE modules. The MPS resides in a 7204 router. Each MPC has one LEC enabled. The MPS has two LECs enabled, one for each of the two ELANs. The LECS and LESs reside in the 7204 rout..
Mitigating the Detrimental Effects of BGP with MPLS Restart
you learned that the BGP graceful restart mechanism allows a speaker to announce its capability to preserve the BGP-related IP forwarding state across the BGP restart. The BGP with the MPLS graceful restart mechanism[5] extends the BGP graceful restart procedure to MPLS. In essence, during the establishment of the pre-restart BGP session, an LSR informs its peers about its capability to preserve the MPLS forwarding state across the BGP restart. When the LSR restarts, its pee..
To participate in STP, each port of a switch must progress through several states. A port begins its life in a Disabled state, moving through several passive states and, finally, into an active state if allowed to forward traffic. The STP port states are as follows: ■ Disabled—Ports that are administratively shut down by the network administrator, or by the system because of a fault condition, are in the Disabled state. This state is special and is not part of the n..
