Here is a sample configuration of ISIS for Cisco routers. This example is a level2 only zone (like a backbone area 0 in OSPF).
Note : Loopback addresses are (or should be) always configured with /32 netmask.
It's a good practice to dedicate a contiguous range for all your loopback addresses, this range is most of time the first of your supernet (i.e. your "big" network allocation), or the one with a zero.
Let's begin to create an loopback interface and annonce this IP (In this example we will use the first /24 of our "big" range for loopbacks) :
ip address 10.0.0.1 255.255.255.255
ip router isis
We configure the physical interface, annonce the connected range in ISIS and lower hello interval to 1 second :
ip address 10.10.10.8 255.255.255.252
ip router isis
isis network point-to-point
isis metric 20 level-2
isis hello-interval 1
And finally the configuration of the protocol :
no hello padding
spf-interval 1 1 100
lsp-gen-interval 1 1 100
metric-style wide level-2
passive-interface loopback 100
Each node in ISIS must have a different "net" (= ID), it's a good practice to begin with 49 and end with 00 (see links below).
It is really important to lower sfp-interval to get a faster convergence (~1sec) , lsp-gen-interval helps also but only a few compared to sfp-interval.
Padding is useless (come on, MTU to 9000 for everybody!), so we deactivate it. And we don't need to generate hello packets on the loopback interface, never.
Here are a few commands really important to troubleshoot :
sh isis neighbors
sh isis database
sh isis topology
sh ip route isis
And if you need to announce/originate a default route (make sure your routeur knows how to reach "THE Internet", blackhole spotted otherwise) :
default-information originate always
I definitelly recommand reading :
and, if you have a lot of time, and some Juniper knowledge, is wonderful post :