Polycom uses CDP???!!!

[chipk]

Ok, so we are installing an Asterisk PBX and went with Polycom phones. I'm the network guy, not the phone guy, so I've been involved only peripherally.

Can anyone explain to me why these stupid phones use CDP to decide which VLAN they belong in? I have all Cisco switches in a multiple-vlan, routed environment. I figured these phones would be smart enough to use the "switchport voice vlan 999" on the access interfaces. However, it ignores that, and appears to go to whatever vlan the PBX tells it to. This is beyond stupid to me.

Why aren't these phones smart enough to pick up a voice vlan from teh Cisco device? Is there a way to remedy this? CDP is a security risk anyway, and if I want to turn it off, now I can't because the Polycom phones rely upon it.

Any help/direction would be greatly appreciated.

 

[segment]

CDP is used on Polycoms to ask your switch what VLAN ID the phone should use without requiring manual configuration of the phone. If you're not using VLAN's you can turn it off in the phone configuration menu

perl -e 'print $i=pack(c5,(40*2),sqrt(7600),(unpack(c,Q)-3+1+3+3-7),oct(104),10,oct(101));'

 

[chipk]

Unfortunately the separate vlan is required because of the number of phones and for traffic prioritization. This still sounds crazy to me because I have Avaya and Cisco phones that don't use CDP to find the vlan. Thanks anyway.

 

[Sympology]

I'm kinda guessing here and I can't speak about the Polycoms, but you'll proberbly find that the discovery for the Cisco Vlans is a proprietary Cisco protocol. Many SIP phones don't fully support Cisco gear as they are true open standard phones.

Only the truly stupid believe they know everything.
Stu.. 2004