GillettPetree626

To pass the BSCI exam and earn your CCNP, you've got to know ISIS inside and out. There are several similarities among ISIS and OSPF, but a single significant difference is that ISIS has three distinct types of routers - Level 1 (L1), Level two (L2), and L1/L2.

L1 routers are contained in a single region, and are connected to other places by an L1/L2 router. The L1 uses the L1/L2 router as a default gateway to reach destinations contained in other places, a lot like an OSPF stub router makes use of the ABR as a default gateway.

L1 routers have no particular routing table entries regarding any destination outdoors their own place they will use an L1/L2 router as a default gateway to reach any external networks. ISIS L1 routers in the very same place ought to synchronize their databases with each other.

Just as we have L1 routers, we also have L2 routers. Anytime we're routing between locations (inter-place routing), an L2 or L1/L2 router need to be involved. All L2 routers will have synchronized databases as properly.

Both L1 and L2 routers send out their personal hellos. As with OSPF, hello packets let ISIS routers to type 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 very same link, they will not type an adjacency.

An ISIS router can act as an L1 and an L2 router at the exact same time these routers are L1/L2 routers. An L1/L2 router can have neighbors in separate ISIS areas. The L1/L2 router will have two separate databases, though - 1 for L1 routes and an additional for L2 routes. L1/L2 is the default setting for Cisco routers operating ISIS. The L1/L2 router is the router that tends to make it feasible for an L1 router to send data to another region.

In the next component of my ISIS tutorial, we'll take a far more comprehensive look at these ISIS hellos! --- Bloco de notas --- Não é possível encontrar "csv" --- OK  --- --- Bloco de notas --- Não é possível encontrar "csv" --- OK  --- --- Bloco de notas --- Não é possível encontrar "csv" --- OK  ---