[c-nsp] holdtime for DIS in ISIS

[Shiraz]

Hi all,

I'm having a small network where 3 - 7200 boxes are connected to each other
via a 2950 switch and running ISIS on pretty much default configuration. All
3 routers have established L1 adjacency only with each other.

One of the routers (RouterA) has been forced to be DIS on this LAN by
increasing its priority to 127 (isis priority 127 interface conf. command).

Now the question is that why "holdtime" of the DIS for its 2 neighbors
appears to be lot lesser than the normal hold time for ISIS adjacency.
Following is output from one of the neighbors (RouterC) of DIS (RouterA):


RouterC>sh clns neighbors 

System Id      Interface   SNPA                State  Holdtime  Type
Protocol
RouterA          Fa0/0       0001.c90a.e006      Up     7         L1   IS-IS
<< "holdtime less than 10 seconds"
RouterB          Fa0/0       0015.2ba8.751b      Up     26       L1  IS-IS


Due to presence of a wireless link (end-to-end Ethernet which is not in a
good condition) between RouterA and RouterC, the L1 adjacency between
RouterA and RouterC often breaks.

Any help? Should I increase the hello-multiplier of RouterA to increase the
holdtime? What is the actual reason of holdtime to be lesser incase of a
DIS?

BR.