The other day we had a major network upset that took out the two redundant network core switches that supply our new corporate office. Loss of the core switches meant that the phones also lost contact with the Branch Offices. This was remedied in about half and hour. What happened next is interesting to say the least.
Most phones came back within 15 minutes of the restoration of the network. However a significant number, some 15% or so, sat there saying "UNABLE TO LOCATE DHCP SERVER". Several others said "INVALID TN" and requested a RESET (one key labelled) and then expected a new TN to be input.
As it happens, the phones had been slated for a firmware upgrade from 0604D9C to 0604D9F. Aparently this was bogging things down because the network had effectively reset all the phones and they were simultaneously trying to upgrade their firmware. Eventually all the phones seeking DHCP eventually found it and went on their merry way. This was not the case for the others with the invalid TNs.
The invalid TN phones required manual intervention. What had happened was that the phones had lost the first digit of their TNs. For example a phone's TN was 64.06 or 75.07 or 85.10 then they would report their TNs as 04.06 or 05.07 or 05.10. there were only about 6 phones like this out of 400 or so. Eventually this place will have 1200 phones so a glitch like this could become significant.
Has anyone had similar experience with these kinds of problems?
SD
03-09-2006, 01:29 PM 
Nortel VoIP Woes 
Linear Mode
