Connecting Cisco Switches to Avaya/Polycom/HP and Etc Phones

Only Cisco & Mitel phones will use CDP to discover the Voice VLAN, however other methods exist to inform the IP Phones of the voice VLAN. Ericsson/Aastra, Nortel & Avaya all use DHCP they boot on the access VLAN and via DHCP options discover the Voice VLAN, they then release the IP address and restart using 802.1q tagged frames.
Although the functionality of an Access port configured like this:

CODE

switchport mode access
switchport access vlan 10
switchport voice vlan 100

is the same as a trunk configured like this

CODE

switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
switchport trunk native vlan 10
switchport trunk allowed vlan 10,100


There are other implations of hard-coding the port as a trunk which is why I wouldn't recommend it.

I have sucessfully deployed several Nortel, Ericsson & Mitel IP Telephony systems using access ports with voice vlans.

Back to the original problem though... Are you plugging the phones directly into the switch using a fully-wired patch cable (i.e. not via the infrastructure cabling)? Are you trying to hard-code speed & duplex (don't....). Have you done any debugging?




I've always understood from Cisco that non-cisco devices should have a proper .1q trunk configured.

For example:
http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a0080891554.shtml

It doesn't make a huge difference, I suppose, because you end up with something similar in either case.

Like you, I have deployed Nortel, Ericsson and Siemens IP phones using my particular bias when it comes to switch configuration. :)

Not that I've often had power issues. Once I found a switch that was refusing to grant power due to being "out of memory", which was somehow caused by a damaged stackport.

LLDP - now theres a thing. Yes this should work but its only supported on the newer Catalysts (2960, 3560, 3750) and 6500's. For some reason (to sell more product...) Cisco have refused to add LLDP to the older switches. I know Nortel support LLDP as well as the newer Cisco IP Phones. Ericsson/Aastra certainly don't in the latest firmware but its supposed to be coming? Not sure about Mitel or Avaya?


I have some Polycom phones going to an Adtran T1 L3 switch (PoE, basically a Cisco!) that they say can use CDP. The phones are SPIP-500/501

I recall HP switches used CDP until firmware updates in 2005/2006.

Don't forget Cisco supports LLDP, though, if your phones support it.

Avaya does support LLDP. Avaya phones also work with either switchport voice vlan OR 802.1Q trunk ports using DHCP/Text files to configure VLAN assignment.

I have heard, If we add one by one Avaya or Nortel IP Phones to cisco switches (mostly 48 port), SOME TIMES last couple of phone finds not enough power to bootup. This usually happens when all the 48 ports are used.

Courtesy
http://www.tek-tips.com/viewthread.cfm?qid=1517008&page=1