Voice vlan for IP phones

[jinhoffoyc]

Hello,

I have a very annoying problem here. The initial setup was done by a 3rd party company but no one knows about the details. When I initialize an IP phone, I always have to connect to the normal ‘access vlan’ port to get an IP from the DHCP server first. And once the configuration importing job is completed through web access, I need to move the cable connection to the ‘voice vlan’ port otherwise phones are not operating properly. *with the voice vlan ports, IP phones are not able to receive any IP addr. and access & voice vlan IDs are the same.

This is my first experience using ‘voice vlan’ command, so not too sure which part I have to start for troubleshooting though..

I appreciate your advice in advance!

Thank you!

[Joseph W. Doherty]

A bit confused by what you describe.  Often VoIP phones are on dual (data/voice) VLAN access/edge ports, but your voice VLAN ports are only that?

[jinhoffoyc]

Yes so what they set up was like this,

1. voice vlan ports for IP phones: switchport access vlan 1000 / switchport voice vlan 100 (vlan 1000 is for public internet)

2. Access vlan ports for IP phones: switchport access vlan 100

As I said the DHCP server is reachable only with ‘2’ and IP phone’s working when connecting to ‘1’ only

Thank you

[Joseph W. Doherty]

Although the voice VLAN is the same for both ports, on port 1, voice frames are tagged but not so on port 2, a significant difference likely contributing to the issues you describe.  DHCP and/or the VoIP phones (and/or possibly other network configuration options) need to be configured for working with port types 1 and/or 2.  I.e., there may be more involved than the switch port configs, alone.

Possibly you can obtain a solution through these forums (the knowledge is here, along with many willing to help) but you might want to get a local contract network engineer to look at this.

[jinhoffoyc]

Noted well thank you for your advice Joseph

[Martin L]

what is switchport config right now? Is there PC connected  switch voice port options should be 

switchport voice vlan {vlan-id | dot1p | untagged | none}

2 valn options (4 ways for voice) are well-explained in following article 

https://www.learncisco.net/courses/icomm-ccna-voice/cisco-uc-solution-maintenance/switch-configuration.html

Regards, ML
**Please Rate All Helpful Responses **

[jinhoffoyc]

I will copy and paste it here when I get it

thank you for the info

[Reza Sharifi]

If the phones are Cisco and laptops/PCs are daisy chained off the phones, vlan 1000 is used for data, and vlan 100 is used for voice, the config should look like this for every port:

interface GigabitEthernetx/x

switchport access vlan 1000
switchport mode access
switchport voice vlan 100
spanning-tree portfast edge

HTH

[jinhoffoyc]

It is one to one and nothing’s connected in the back of the IP phones

[Reza Sharifi]

So, you are using one physical port for each phone and one physical port for each PC/laptop?

If this is the case, you are using twice as many ports as you need to.

HTH 

[jinhoffoyc]

Thanks for your response

Yes but personally I would rather not using the port in the back of IP phones as it doesn’t support gigabit, too slow.

thank you

[Reza Sharifi]

So, in that case, you just need a voice vlan for the phones and one data vlan, all configured as access ports.

Also, can you post the output of "sh run" from your switch?

HTH

[Joseph W. Doherty]

"So, in that case, you just need a voice vlan for the phones and one data vlan, all configured as access ports."

Ditto and would simplify other supporting configuration needs.

[jinhoffoyc]

I will try it.. as I don't have access the switch unfortuantely and the access port command info was from the NOC team.

They said DHCP is running from the core switch though, probably I need to ask them to look into it..

thank you anyway

* this is all I got

interface GigabitEthernet1/0/1
description *** IP Phone **
switchport mode access
switchport voice vlan 100
srr-queue bandwidth share 1 30 35 5
priority-queue out
mls qos trust dscp
auto qos trust dscp
storm-control broadcast level 10.00
storm-control multicast level 15.00
spanning-tree portfast edge

interface GigabitEthernet1/0/2
switchport access vlan 1000
switchport mode access
switchport voice vlan 100
srr-queue bandwidth share 1 30 35 5
priority-queue out
mls qos trust dscp
auto qos trust dscp
storm-control broadcast level 10.00
storm-control multicast level 15.00
spanning-tree portfast edge

[Joseph W. Doherty]

I think what @Reza Sharifi also had in mind would be:

interface GigabitEthernet1/0/1
description *** IP Phone **
switchport mode access
switchport voice vlan 100
switchport access vlan 100

interface GigabitEthernet1/0/2
description *** Data only **
switchport access vlan 1000
switchport mode access
switchport voice vlan 100

The above would create untagged data and voice ports, with a VLAN for each.