NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
Solved
Voice VLAN command - LLDP seems to stop working
I have a strange issue with the voice vlan command that I'm trying to isolate between our switches and Shoretel phones, but it seems there's no debug options for LLDP on this switch.
We use the...
FWIW this issue seems to be fixed. Originally the config was
interface 1/0/1
voice vlan 10
switchport mode access
switchport access vlan 20
But the switch would randomly stop passing the tagged VLAN traffic. I changed the config to:
interface 1/0/1
voice vlan 10
switchport mode trunk
switchport trunk native vlan 20
switchport trunk allowed vlan 10,20
I haven't had a single DHCP failure/VLAN tag drop since moving to this config.
This behavior seems to only occur on the M4300 series - the M4100 actually rejects switchport mode access as a valid option when using voice VLAN (I have those access ports configured in general mode but I'll be updating them later for the sake of consistency). Maybe it would be nice in future updates to prompt users to use a trunk config when enabling voice VLAN on switchports so they don't spend their time flailing about like I did (this problem lasted for like, seven or eight months!). :)
To be clear, it wasn't LLDP failing to maintain the voice VLAN tag, it was the switch refusing to pass tagged traffic and the phone dropping the VLAN tag after DHCP repeatedly failed (which is normal Mitel/Shoretel behavior).
If anyone else googles this problem hopefully they find this post. :) :womanvery-happy:
We have a stack of six s3300 switches and I think we may be seeing the same thing. Have been using voice vlan for a couple years now and it's worked fine with polycom cx600s. All of a sudden today our data dhcp scope filled up and we noticed a lot of the polycoms are on the data vlan. Anyone heard any more on this? We are going to scheduled a reboot for after-hours.
Hi,
We experienced that issue on a single location. On a 2nd location, we never had that problem.
- On the problematic location, we used the default voice vlan, vlan #2.
- On the other location, we used a different voice vlan number than the default one.
- Exported and compared both config file.
- On the problematic location, found some LLDP network-policy configuration that was not part of our 2nd location switch. (lldp med network-policy 1 app voice mode vlan-id val 2 cos enable auth enable dscp 46)
- Removed these extra lines from the problematic switch config file
- Reload that modified config file into the switch
No new occurrence since...
NETGEAR Academy
Boost your skills with the Netgear Academy - Get trained, certified and stay ahead with the latest Netgear technology!
Join Us!
