Adjacancies IS-IS uses Protocol Data Units, or PDU’s to communicate. This is like a packet in OSPF terminology. An IS-IS Hello PDU, or IIH, ...

NET Value A Network Entity Title, or ‘NET’, is an address that identifies the router. It consists of the router’s system ID, and the area a...

Inter-Area Routing To route a packet outside an area, a level 1 router sends the packet to the nearest level 2 capable router. The nearest r...

Level 1 routers will only share routing information with other Level 1 routers. This makes them stub routers. In the topology above, area 40...

Like OSPF, IS-IS uses areas. Areas can be either a backbone area, or normal area. To support this concept, a router may be one of the follow...