Voice VLAN vs. VLAN fields

[FSaucedo]

hi all, 

we are reconfiguring switch ports for our new VoIP phones and are wondering what/how the two different VLAN fields work in the port configurations.  I looked through the documentation but it was not very detailed. All it says:

So now I am hoping someone who has worked with these can help clarify. 

Just so you know, we can set VLAN to 50 and leave Voice VLAN empty, the phone connects properly. If we leave VLAN with default 1 and set Voice VLAN to 50, the phone does not connect correctly (it adds it to VLAN 1). If we use both at 50, the phone connects properly. Do we set both to 50 (our VLAN ID for phones) or do we just use the Voice VLAN fields and set the VLAN on the phone itself to specify teh VLAN ID?

Thanks in advance!

[ww · Accepted solution]

It is for phones with integrated switch. You could connect a client behind the phone.

https://documentation.meraki.com/MS/Port_and_VLAN_Configuration/Configuring_the_MS_Access_Switch_for...

[FSaucedo]

After all of that searching, I could not find this. Thank you!

[Mloraditch]

The voice vlan field enables CDP/LLDP to send that vlan number to a properly enabled device and it will put itself on that vlan. Those devices will be IP phones or ATAs usually.

The errors you are experiencing sound like the phones are not handling the info properly. Suffice it to say there are some unique situations with various vendors where the CDP/LLDP info may not work right for a variety of reasons. Sometimes you have to enabled cdp/lldp on the phones, sometimes they use dhcp options for vlans, sometimes old dhcp options may interfere.

Based on what you are posting both vlans work in and of themselves so that leads to me to think something is up with the phones. 

Can you tell us what manufacturer/model of ip phones you are using and with what type of pbx?

[RaphaelL]

Both ww and Mloraditch are right. 

Side note , you "can" put the same VLAN ID for both access and voice vlan but it is not recommended and you will end up with issues. Don't do that. 

I have seen some phones that do not use the voice vlan at all and stops working when a voice vlan is configured. I don't remember the SKUs to be honest,  I will have to look at my notes.

[FSaucedo]

They are Vertical VIP9820 phones and our PBX is a Vertical Summit 800. Like I mentioned, the phones connect properly once I set the VLAN ID in the fields.

We just found out that these phones have a UI where you can specify the VLAN for teh phone and the PC if attached so we just added the configuration there and, with @ww help, we were able to properly finish configuring the ports. I was just wondering why there was a second VLAN field and its purpose.

Thanks for your help though!