ok- just checking you left the TLan unplugged for 30-60 secs to verify ?
a few thoughts ...
double check config - mentioned previously - make sure 2md NRS is set to alternate and not failsafe per say along with proper IP settings
- was the 7.5 failover ever tested to know for sure it worked originally ? Assuming previous Nortel releases used same network connection (ie 4.9,5.0,5.5) did it actually work as advertised on previous releases.
- your remote site may be a private network but are you Layer 1 via "dark fibre" or through a managed service ( MPLS or some type of layer 2/3 service)
- Rlse 7.5 - turn on your PCAP (Primary NRS)and collect the packets for a few minutes. Both scenarios - TLAN connected and TLan disconnected on Primarary NRS - my terminolgy is probably wrong but you should see the keep alive and heart beat type stuff from the remote system.- something that the alternate NRS is verifying the Primary is alive.
- If error isolation still in doubt then if you have the equipment at the main site configure an Alternate NRS on the 2nd SS and test - you will have to change config on all SS to reflect the change. This setup should take the other variables out of play.
Only some food for thought...
TGD