Avaya VOIP phone reboot on Cisco Network


Why would a small group of users would have their Avaya ip phones boot on them when a call comes in?

I have a 2 building network, building one is all Cisco 6500vss in the core and all on native vlan.  The access and distribution layers are a mix of Cisco, Foundry and HP in the process of moving to all Cisco and implementing vlans as we go.  All the Avaya IP Phone server/call managers are on vlan 1 plugged into access layer equipment.

In building two we have all Cisco and a routed link between both building over a 8gig etherchannel on SM fiber between two Cisco 6500vss core switches.  There is no vlan 1 in building 2 all the PCs and phones are on the same vlan 560 and plugged inline to each other.  There are no high bandwidth applications so it was recommended to us by a VAR that we do not(almost regretting this now) QOS the voip traffic.

This handfull of users gets their calls bumped on they 1600 series Avaya phones at the start of a call.  We believe the cable plant is all below the 100meter mark for POE.  All the phones are currently POE, however we are testing an inline power for one user with the problem.  As of yet we have not validated any pairs being open on the cable in the wall.

The network is being blamed for this issue, and I am open to the idea that its the network however the group of people that have the problem continue to have the problem whereas other people dont have the problem at all or are completely terrified to report the problem.  I dont see how a network problem could tell a phone to boot at the beginning of a call.  If it was a network interuption with POE you would think that the ip phone would boot at random.  Same if it was a cable plant issue.  

Building 2 has about 120 people in it, about 10 people have reported the issue.  Im pretty good with networking but I am a noob when it comes to voip.

Any help on this issue is greatly appreciated.
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are these phones powered by PoE?  If so, they may be exceeding the power supply upon ring.

That would explain why it takes out a group (the same group).
Also, only upon ring...but not _always_.

The ring will draw more power, but if all users are not touching their phones...it may just be under the max to trip the PoE power supply/injector.

If there is one or more people on the handset, the power requirements go up.

Same goes if the ring is hitting more than one unit...such as a group ring or a shared line appearance.  Two phones ringing draws more juice than just one.

Also...if the power supply is near max (or acting flaky) it could be just random that one ring trips it, while another doesn't.
Eric-arupAuthor Commented:
Sorry forgot to mention something, isnt that always the case 10 seconds after you post.

We too a data capture of the voip traffic, we cant capture the problem on demand as it cant be reproduced on demand.  In that capture for the RTCP packets we saw no OOS and no lost packets.  We did see a small ammount of UDP Jitter but nothing higher then 40ms and usually is was ZERO or 10ms.

You can check the power use on the Cisco switch, and the class of individual phones.  Also, turning on lldp may glean something out of the phones.

One of these (http://www.cyberguys.com/product-details/?productid=18358) might help if it's a poe problem.

switch01#show power inline
Module   Available     Used     Remaining
          (Watts)     (Watts)    (Watts)
------   ---------   --------   ---------
1           370.0      260.0       110.0
2           370.0      262.4       107.6
3           370.0      227.8       142.2
4           370.0      239.4       130.6
6           370.0       43.4       326.6
switch01#show power inline Gi1/0/24
Interface Admin  Oper       Power   Device              Class Max
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/24  auto   on         7.0     Ieee PD             2     15.4
Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------
Gi1/0/24              15.4                 15.4

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Eric-arupAuthor Commented:
sorry for the late response, I was out on a unexpected medical issue the day after I asked this questions.  I'll award points anyway.

Other people are now working on the issue, I think some duplexing errors were found on the nic inside the phone switch.
Can you update this on what you found to be the problem? I have a similar thing going on at a site.
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