DHCP Binding

jaime.garcia · ‎09-10-2010

Every morning some of my IP Phones are stuck on Configuring IP. I run the command Clear IP DHCP Binding * and the phones come back up. I have also created a new voice VLAN just because we were short on IPs. But now that I have created a new voice vlan I am still having to run Clear IP DHCP Binding * on the router.

Current IOS: Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(20)T1, RELEASE SOFTWARE (fc3)

DHCP Config:

no ip dhcp use vrf connected
ip dhcp excluded-address 10.200.1.254
ip dhcp excluded-address 10.200.1.1 10.200.1.30
!
ip dhcp pool Voice-VLAN
   network 10.200.1.0 255.255.255.0
   default-router 10.200.1.254
   option 150 ip 10.200.1.5
   lease 3

My other voice vlan DHCP is configured on a Windows Server. Its on network 10.201.1.0 255.255.255.0

Any ideas of what to do to resolve issue?

Thanks,

Jaime

andrew.prince · ‎09-10-2010

How many phones do you have in the vlan? Make sure no PC's are connected to the voice vlan.

jaime.garcia · ‎09-10-2010

Hi Andrew,

We have currently 180 phones in voice vlan 200 and 40 in (new) voice vlan 201.

Switch ports are configured as follows. We are using the 10/100 ports on the IP Phones for PC connectivity. Do you think that is causing an issue? From what I can tell PCs are grabbing ip addresses for data vlan 20 (Windows DHCP Server).

switchport access vlan 20
switchport voice vlan 200
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
priority-queue out
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
no mdix auto
spanning-tree portfast

and

switchport access vlan 20
switchport voice vlan 201
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
priority-queue out
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
no mdix auto
spanning-tree portfast

Thanks,

Jaime

andrew.prince · ‎09-10-2010

Do you have a layer 3 interface in vlan 201? Does the mac address table in the switch and the arp table in the router for vlan 201 match? Are there any mac/arp entries that exist in both vlan 20/201 ?