Collection of IS-IS Labs

A collection of IS-IS labs created by me, during CCNP Studies.

1. Based around a Frame-Relay Backbone, with 3 areas and their L1/L2 routers. Download project files



2. A different and more complex topology, with Frame Relay p2p links and other good stuff thrown in. Download

IS-IS Authentication

1-) Clear text:

# router isis
# isis password MyPaSS

2-) Area password:

# router isis
# area-password YesAnAreaPass

3-) Domain password:

# router isis
# domain-password ThisWouldBeEasy

4-) MD5 Authentication:

Use it either under an interface or the whole router process; first create your key-chain. (Eg: keyISIS)

# interface s1/0
# isis authentication key-chain keyISIS
# isis authentication mode md5

or under router process

# router isis
# isis authentication key-chain keyISIS
# isis authentication mode md5

you can also limit it to level-1 or level-2 and send-only

# isis authentication mode md5 { level-1 | level-2 }
# isis authentication send-only { level-1 | level-2 }

IS-IS Pseudonode and DIS (Designated IS)

In IS-IS a broadcast link itself is modeled as a pseudo-node that connects all attached routers to a star topology.
The pseudo-node is represented by the DIS (Designated router)



On broadcast type links a DIS is elected for both Level-1 and Level-2, if they exist.
A router with highest priority or highest SNPA (MAC,DLCI,..) address is selected as DIS.
Default priority is 64. (can be between 0-127)
DIS election can be preempted, any priority change will take effect immediately.

There is no backup DIS (unlike OSPF) and all routers in a LAN establish adjacencies with each other and the DIS.

The DIS creates and maintains the pseudo-node LSP.
This LSP contains the adjacent ISs, just like the network lsa in OSPF.