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polycom phone wont get DHCP address from voice vlan

We have Polycom 501 and 601 phones as well as cisco 7940 phones connected to cisco 3560 switches. We have VLAN 1 for data and VLAN 20 for voice. Last November we added VLAN 50 for data traffic instead of VLAN1. Everything worked fine until last week when the Polycom phones began to fail. When we rebooted them, they failed to get an IP address via DHCP. A cisco phone placed in the same port came up fine as does the PC. The phone gets its IP address from an Edgemarc Router on VLAN 20. The PC will get its ip address from a windows DHCP server from the Data VLAN (VLAN 1 or VLAN 50). When we removed the switchport access vlan 50 statement from a port that a Polycom phone connected to the phone received an ip address and works fine. I have no other vlans. The switches all directly connect back to our 6509 (which the Edgemarc router connects directly into). We have made no changes to our network in the last four months.

I have tried trunking the switchport but it still wont get an ip address if we have set up to access vlan 50. I can really use some hlep on this one.

Thanks!
interface FastEthernet0/3
 switchport access vlan 50
 switchport voice vlan 20
 speed 100
 duplex full
 spanning-tree portfast
end

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frizzell
Asked:
frizzell
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blue-screenCommented:
How does the Polycom learn the VLAN?  Some devices using the default VLAN (1) to make a DHCP request to pick up the VLAN information from the DHCP server.  That would explain why the loss of VLAN 1 caused the problem.

The Cisco IP phones use CDP to learn the VLAN, which is why they would work.  Are the Polycoms set to use CDP?

The port is set to "switchport mode access,"  right?
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frizzellAuthor Commented:
Polycom phone has CDP enabled. If my access vlan 50 statement is removed the phone picks up the voicevlan 20 and the user picks up the data vlan 1.

I did not have switchport mode access set, but i just tried it and the phone still wont pick up a DHCP address.  
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blue-screenCommented:
The next thing I would go next is compare the Wireshark packet traces in both situations (Vlan 1 and Vlan 50) and compare to the working Cisco phone.  Either the wrong CDP information is provided, or the Polycom is interpreting it incorrectly.

An interesting test might be to add a VLAN 1 to that port that does nowhere and see if the mere existence of a VLAN 1 (even without a DHCP server) causes the Polycom to work.

At this point, you need packet traces to figure out who is at fault.
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frizzellAuthor Commented:
I have not had a chance to run a packet trace on the phone yet. I should be able to get to it Thursday.
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frizzellAuthor Commented:
I did some traces on both a cisco phone with VLAN 50 enabled on the port and not as well as a Polycom. both phones worked fine without VLAN 50 enabled and the Cisco phone worked fine with VLAN 50 enabled. The Polycom sees vlan 20 (the voice vlan) it sends out a DHCP request and the DHCP server sends an IP address, but the Polycom phone does not seem to see it.
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blue-screenCommented:
Did anything else change before it started failing?  Firmware updates on the phones or the EdgeMarc?
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frizzellAuthor Commented:
Sorry for the long absence - Nothing was changed on the network that i am aware of or could find (thats what is freaking me out). It is not relegated to just one switch in our network - it is all them.
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blue-screenCommented:
Seeing the packet trace might be inetersting - but it seems like a bug in the Polycom Phone.
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frizzellAuthor Commented:
According to the trace it looks like my problem is with the Polycom phone and will start working on that. Thank you for the help
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