04-19-2010 07:06 AM - edited 03-15-2019 10:20 PM
Ok this is a weird problem. My Cisco phones at random times (days or weeks)
and random phones (different buildings) are getting a data vlan IP address.
The phones are still up and when a user can receive (phone rings) and call
other extensions but when they connect the phone goes busy. If you power
cycle the phone it will receive a new IP address on the voice vlan. I think
it is losing the voice vlan IP and getting the data vlan IP when the lease
is up and it tries to request an IP again. But like I said if you power
cycle it will get the voice vlan IP, confused.
<br>
I am assuming this is a routing program since it is coming across vlans to
get the data vlan IP. We have 2 separate vlans on 2 different DHCP server.
The data vlan DHCP server is windows server 2003 and the Voice vlan is
currently on our cisco 4507r. We did have a server 2000 box with the
DHCP server for the voice vlan but changed it when we had the phone system
upgrade. I had ip helper-address pointing to the DHCP server and still had
phones getting a data vlan IP.
<br>
The 4507r is the core of the network. The Cisco Voice servers are connected
to the gi eth ports on the 4507. The data vlan DHCP server is also connect to
the gi eth ports on the 4507r. The vlans are configured for the ports.
<br>
It is only happening with Cisco IP Phones 7970 series phones.
<br>
We have had this problem since before I started here about 2 years ago. We have
updated the phones verions several times without out a resolution. Also we
recently upgraded to CUCM to the latest and still have this problem. The phone
vendor is looking into this still but I thought maybe there was traffic issue
or a route confusion somewhere that might be a vlan or routing problem.
<br>
I am lost and do not know where else to look to try and trouble shot this.
04-19-2010 09:41 AM
How are your switches configured ("switchport voice vlan" or manually configured dot1q trunks)? Are all of the effected phones on a particular switch? Why do you need an IP Helper command?
What you describe can be caused by VLAN leakage, when misconfigured Native VLANs cause traffic from one VLAN to seep into another VLAN. It can also be caused by IP Helper commands, so I'm courious how those fit into all of this.
04-19-2010 10:45 AM
The switches are configured
4507r client ports
switchport access vlan 10
switchport mode access
switchport voice vlan 172
qos trust cos
qos trust device cisco-phone
tx-queue 3
priority high
shape percent 33
spanning-tree portfast
service-policy output auto-qos-voip-policy
3560 client ports
switchport access vlan 10
switchport trunk ecapsulation dot1q
switchport mode access
switchport voice vlan 172
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
spanning-tree portfast
The ip helper was just a troubleshooting step. Thought I forward all the request to the DHCP server that it needed to receive the IP address. I currently do not have it on.
The Native VLAN 1 is used for all the VLANs.
08-09-2023 09:02 PM
Any solutions to this??
08-10-2023 12:17 AM
@anish.gupta11 Please do not ask the same question on multiple posts. https://community.cisco.com/t5/ip-telephony-and-phones/7821-phones-registered-in-data-vlan-without-dhcp-option-150/m-p/4037801#M386856
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