Clustring WM6.5

Hi ,

I am facing a problem in clustering WM 6.5
I am having two IS running in diff m/c .I have single repository of file system running in m/c A .
should i do configuration settings in both the IS ?
I did the configuration for both the IS
In one IS i am able to see both the IP(hostnames) in cluster hosts.
But in the other IS under the cluster hosts tab ,i am able to see only one cluster host .
what is the problem ?
What is the value i have to give for the node identity ?whether the IP address of the same machine or the Ip address of other machine.