RIP Convergence and Loop Prevention
The most interesting and complicated part of RIP relates to loop-prevention methods used during convergence after a route has failed. Some protocols, like OSPF, IS-IS, and EIGRP, include loop prevention as a side effect of their underlying route computations. However, RIP, like other distance vector protocols, uses several loop-prevention tools. Unfortunately, these loop-prevention tools also significantly increase convergence time—a fact that is certainly the biggest negat..
Hello packets are sent to multicast MAC-layer addresses to determine whether other systems are running IS-IS. There are three types of hello packets in IS-IS: one for point-to-point interfaces, one for level 1 routers, and one for level 2 routers. The hellos sent to level 1 and level 2 routers are given to different multicast addresses. Therefore, a level 1 router connected to a common wire where a level 2 router resides does not see level 2 hellos, and vice versa. ..
NLSP is a link state interior gateway protocol for IPX networks. NLSP, which is based on the OSI Intermediate System-to-Intermediate System (IS-IS) protocol, has features similar to those of other link state protocols, such as OSPF. Like other link state protocols, NLSP supports hierarchical addressing and fast convergence. NLSP has the capability to use hierarchical routing techniques to aggregate and summarize IPX network numbers. Route aggregation and summarization are us..
Bridges provide more user bandwidth by reducing the number of devices contending for the segment bandwidth. But bridges also provide additional bandwidth by controlling data flow in a network. Bridges forward traffic only to the interface(s) that need to receive the traffic. In the case of known unicast traffic, bridges forward the traffic to a single port rather than to all ports. Why consume bandwidth on a segment where the intended destination does not exist? Transparent ..
A campus network’s core layer provides connectivity of all distribution-layer devices. The core, sometimes referred to as the backbone, must be capable of switching traffic as efficiently as possible. Core devices, sometimes called campus backbone switches, should have the following attributes: ■ Very high throughput at Layer 3 ■ No costly or unnecessary packet manipulations (access lists, packet filtering) ■ Redundancy and resilience for high availability ■ Advanc..
