[cisco-voip] 7936 DHCP issue

[Mike Armstrong]

It sounds like the 7936 doesn't completely understand DHCP.   If you unplug 
the 7936 and reconnect to the same VLAN (perhaps thru a different 
switchport, if possible) does it come up OK with the same IP address it had 
before?  If so, try unplugging it and removing that address from the DHCP 
pool, and see if the 7936 can get another IP from the same pool.  Then, try 
the other VLAN; these test should identify the point in the DHCP handshake 
where it breaks.  Also, what is your lease time -- how does that compare 
with the "several hours" it takes to acquire a new IP on the 2nd VLAN?  If 
you can sniff the switchport when the 7936 is plugged it, it would be an 
interesting trace compared with, say, a 7940 doing the same dance.  We've 
had several problems with the conference phones' initialization, but never 
pinned anything down.

Mike Armstrong
UF/IFAS CREC
Lake Alfred, FL

> Date: Mon, 20 Feb 2006 15:08:24 -0600
> From: "Mike Mike" <voipermike at gmail.com>
> Subject: [cisco-voip] 7936 DHCP issue
> To: cisco-voip at puck.nether.net
> Message-ID:
> <8bbfc1f40602201308x1f224394r878602afaaa26d0b at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Conference phone gets plugged into a port on the first voice vlan and gets
> an IP from the DHCP pool no problem. Customer moves to another switchport
> (same switch) configured on one of the other voice vlans and it takes
> several hours to pull a new IP. Customer is using a different voice vlan 
> for
> each of three floors. The 7936 has the latest firmware but also 
> experienced
> the problem on previous version. Also, a new conf phone has been tried 
> with
> same results. Moving 7940's and 7960's between floors works just fine. 
> Last
> test was to create reservations in each pool but apparently that didn't
> work. Anyone else seen this behavior with the 7936?
>
> Thanks