DonnieGorton579

出典: くみこみックス

To pass the BSCI exam and earn your CCNP, you have got to know ISIS inside and out. There are numerous similarities between ISIS and OSPF, but one particular key distinction is that ISIS has 3 various kinds of routers - Level 1 (L1), Level two (L2), and L1/L2. L1 routers are contained in a single location, and are linked to other places by an L1/L2 router. The L1 utilizes the L1/L2 router as a default gateway to reach destinations contained in other regions, a lot like an OSPF stub router uses the ABR as a default gateway. what is an ionizer L1 routers have no precise routing table entries regarding any destination outdoors their own area they will use an L1/L2 router as a default gateway to reach any external networks. ISIS L1 routers in the same area must synchronize their databases with each other. Just as we have L1 routers, we also have L2 routers. Anytime we're routing in between places (inter-region routing), an L2 or L1/L2 router should be involved. All L2 routers will have synchronized databases as properly. what is an ionizer Each L1 and L2 routers send out their personal hellos. As with OSPF, hello packets enable ISIS routers to form adjacencies. The essential difference right here is that L1 routers send out L1 hellos, and L2 routers send out L2 hellos. If you have an L1 router and an L2 router on the exact same link, they will not form an adjacency. tumbshots An ISIS router can act as an L1 and an L2 router at the very same time these routers are L1/L2 routers. An L1/L2 router can have neighbors in separate ISIS places. The L1/L2 router will have two separate databases, though - one particular for L1 routes and another for L2 routes. L1/L2 is the default setting for Cisco routers operating ISIS. The L1/L2 router is the router that makes it achievable for an L1 router to send information to another location. In the subsequent portion of my ISIS tutorial, we'll take a much more comprehensive appear at these ISIS hellos!