06-20-2011 02:08 AM - edited 03-16-2019 05:32 AM
Dear All,
I have one-way audio issues with IP phones 7962G connected to a catalyst 3750. The problem is calling between two IP phones one the same switch and same VLAN.
The scaniors are as follows:
1. Both IP phones on the same switch and same VLAN. The called phone rings but there is only one-way audio.
2. Both IP phones on the same switch but different VLANs. No problem at all.
3. Each IP phone on different swicthes but on the same VLAN. No problem at all.
I have also done wireshark capture and see ARP request sent by one of the phones but unanswered.
Catalyst 3750
IOs version: 3750-ipbasek9-mz.122-55.SE3.bin
Port Settings:
interface FastEthernet1/0/8
switchport mode access
switchport voice vlan 81
ip arp inspection limit rate 100
mls qos trust device cisco-phone
spanning-tree portfast
spanning-tree bpduguard enable
spanning-tree guard root
service-policy input IPPHONE+PC
ip verify source port-security
Thank you in advance.
Solved! Go to Solution.
06-20-2011 03:40 AM
I run loads of phones on this type of switch, without problem.
Try this config just for troubleshooting.
NB - you are using vlan 1 for your datatraffic - is that intentional ??
conf t
!
default int fast 1/0/8
!
interface FastEthernet1/0/8
shut
switchport mode access
switchport access vlan 1
switchport voice vlan 81
spanning-tree portfast
no shut
The purpose of this test is findout if its a port config problem.
06-20-2011 02:30 AM
Remove "msl qos", service-policy, arp inspectio, and ip verify commands and try again.
06-20-2011 02:38 AM
Dear Paolo,
I have tried what you suggested with plain default config and I still have the issue. Strangly it sometimes works even with the config I posted. I think the problem could be related to ARP bordcast. Either the switch is not sending ARP brodcast or the called phone is not responding for the ARP request.
Thanks
06-20-2011 03:40 AM
I run loads of phones on this type of switch, without problem.
Try this config just for troubleshooting.
NB - you are using vlan 1 for your datatraffic - is that intentional ??
conf t
!
default int fast 1/0/8
!
interface FastEthernet1/0/8
shut
switchport mode access
switchport access vlan 1
switchport voice vlan 81
spanning-tree portfast
no shut
The purpose of this test is findout if its a port config problem.
06-20-2011 03:45 AM
Dear Keanej,
No I don't use VLAN 1 as data VLAN. It was a type when I posted the config. The port is configured for dynamic VLAN with VMPS support as follows:
switchport access vlan dynamic
06-20-2011 04:24 AM
I've seen this before...
can you please try removing all and any qos config from the switch ?
Or have you resolved already ?
06-20-2011 05:22 AM
I did as you requested. It works the first time and then after a while I had same problem. Can I modify ARP or CAM timeout in Cat 3750?
Another observation: If I set the data VLAN to static on the port or connect a PC to the IP Phone, it is working.
06-20-2011 05:34 AM
So it seems related to dynamic VLAN, is that a absolute need for you?
Or try update IOS.
06-20-2011 05:38 AM
I thought it was IOS issue and I updated it the latest version. As for dynamic VLAN, yes we need it. We run VMPS for data part.
06-20-2011 05:41 AM
Then if you're sure config is right, your only resolution is a TAC case.
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