[Asterisk-Users] Push VLAN to Polycom via DHCP

[Joseph Finley]

Matt Darnell wrote:
> On Mon, 28 Mar 2005 14:29:15 -0600, Jerry <jjones at quiddesign.com> wrote:
> 
>>On Mar 27, 2005, at 12:10 AM, Matt Darnell wrote:
>>
>>
>>>>>Has anyone been succesful pushing a VLAN setting to a Polycom phone
>>>>>via DHCP?
>>>
>>>> Chicken or the egg!  How can the Polycom reach the proper DHCP server
>>>>if it is not on the correct VLAN?  That's why Ciscos and Polycoms
>>>>support CDP, so the CDP-capable switch can supply the correct voice
>>>>VLAN.
>>>
>>>I 'assumed' the phone would reboot with the new VLAN setting and get a
>>>new IP address from the DHCP server on the phone VLAN - there would be
>>>two DHCP servers.
>>>
>>>I can't think of any other way to make it work with DHCP.  If it isn't
>>>designed to work that way, why would they put the option in the DHCP
>>>section.
>>>
>>>-Matt
>>
>>I had always understood that they only supported VLAN discovery via
>>CDP. But reading the 1.4 admin guide it says this...
>>
>>VLAN ID
>>See 2.2.1.2.2
>>DHCP Menu
>>on page 7
>>Special Case: Cisco Discovery Protocol (CDP)a overrides
>>Local FLASH which overrides DHCP VLAN
>>Discovery.
>>a. Can be obtained from a connected Ethernet switch if the switch
>>supports CDP.
>>
>>This seems to imply that DHCP can be used to spec a VLAN.
> 
> 
> 
> Looks like logic has let us down again.
> 
> After talking with Polycom it doens't do what it reads.  Here is the
> quote from the manual:
> 
> ********
> VLAN Discovery
> 
> Disabled - No VLAN discovery via DHCP.
> 
> Fixed - Use predefined DHCP private option values of 128, 144, 157 and
> 191. If this is used, the VLAN ID Option field will be ignored.
> 
> Custom - Use the number specified in the VLAN ID Option field as the
> DHCP private option value. VLAN ID Option 128 through 254 (Cannot be
> the same as Boot Server Option)
> 
> The DHCP private option value (when VLAN Discovery is set to Custom).
> Default is 129.
> *******
> 
> I can't see how that could mean anything else.
> 
> Maybe I should sleep on it.


We run the Polycom's with our phone system here, in my case a Shoretel 
and could not get the Polycom's to work on our VLAN.  We have to 
manually set the VLAN ID and IP address.  We chaulked it up to a CDP 
problem on the Polycom.