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SF200-24P VLAN Assignment to VoIP Phones


I have recently purchased 2 Cisco SF200-24P switched to be deployed in an upgrade to one of my client's networks.

The network will be carrying VoIP data, general data for 2 business and data for guest wireless access.

My idea is to keep all categories of data separate using VLANs.

I have implemented similar scenarios before using VLANs on Netgear and TP-Link switches.

This time I decided to use Cisco switches and at the moment I am regretting my decision because of the time I have had to spend getting the VLANs working on a test setup in my office.

I am using a VLAN aware Draytek 3200 router to provide IP addresses by DHCP with a different IP subnet for each VLAN.

My problem is that VoIP phones (of various types) will not receive an IP address by DHCP if they are assigned a VLAN ID by the PVID on the connected switch port of the SF200.

The curious and annoying thing is that if a laptop, PC or a router is attached to the same switch port it will receive an IP address in the correct subnet.

In other words... if I configure (say) Port 2 of the SF200 as an untagged access port with a PVID of 20 and tell the Draytek 3200 to assign by DHCP IP addresses in the subnet to VID 20 then a VoIP phone will not receive an IP address, but other devices will.

The VoIP phone just hangs waiting for the IP address.

Another curious thing is that I can see that the Draytek has issued the correct IP address to the VoIP phone from the Draytek DHCP table.

I have tried Yealink IP phones, Cisco IP phones, Aastra IP phones and Gigaset IP phones and the same thing happens.

All these phones receive IP addresses without any problem in non VLAN environments and I have used them successfully in similar configurations with other VLAN aware switches.

I can only think that it is something to do with Cisco's Smartport or Auto Voice VLAN functions which other switches did not have.

However, I have tried disabling these functions and it makes no difference.

A two hour job has taken me two days and I have given up and I am seeking help!

Thank you

Stephen Killen

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