Earning your CCNP certification and passing the BSCI exam depends on knowing the details of many Cisco technologies, ISIS chief among them. To help you prepare for exam success, here's a list of ISIS terminology and basic concepts that will help you pass this tough exam. Enjoy! ISIS Terms: Domain: section of the network under common administrative control Area: logical segment of the network composed of contiguous routers and their data links Intermediate System: A router. End System: A host device. The four levels of ISIS routing: Level 0: ES-IS routing in the same subnet. Level 1: IS-IS routing in the same area. Level 2: IS-IS routing in the same domain. Level 3: Inter-domain routing performed by InterDomain Routing Protocol (IDRP). ISIS Adjacency Possibilities: L1: Can form adjacency with any L1 in the same area and any L1/L2 in the same area. L2: Can form adjacency with any L2 in any area, and with an L1/L2 in any area. L1/L2: Can form adjacency with any L1 in the same area, L1/L2 in any area, and L2 in any area. A router interfaces SNPA (Subnetwork Point Of Attachment) is its highest DLCI number if its on a Frame network, and its MAC address if the interface is on an Ethernet segment. ISIS Hello Types: ESH: ES Hello Sent by End Systems to discover a router. ISH: IS Hello Send by Intermediate Systems to announce their presence. End Systems listen for these. IIH: IS-to-IS Hello Send by one IS to be heard by another IS. These hellos makes IS-IS adjacencies possible. Best of luck on your CCNP exams! |
