Cisco CCNP / BSCI Exam Tutorial: 10 ISIS Details You Must Know!
Chris Bryant, CCIE #12933, lists 10 ISIS details you must know in order to earn your CCNP. ccnp, certification, cisco, isis, level, router, end, system, iis, hello, type, adjacency, level-1 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.