I have a number of Nortel IP 2004 phones plugged into a Cisco 3560 switch. The PCs are plugged into the back of the phones however I am experiencing slow upload throughput and can only get around 1-2mbit upstream. Data that is sent downstream from servers plugged directly into a vlan20 switch port is going between 40-70mbit so I that is not a problem.
VLAN40 is for voice
VLAN20 is for data
Here is my Cisco 3560 switchport configuration
switchport access vlan 20
switchport mode access
switchport voice vlan 40
mls qos trust dscp
I have also tried changing the links to trunk lists as per a previous suggestion but that doesn't speed up performance either. Tried changing the voice and data vlan settings on the Nortel phone to tagged and untagged but still no better.
One thing I have noticed however in a test enviroment is when the phone is just powered on before you either get a login prompt from the Nortel server then you can get upwards of 50mbit upstream throughput.
Has anyone come across something like this before or can you provide some suggestions. Are there special options that are given to the phone? Do I need to enable any more special options on the switch?