Cisco 8851 and 8861 phone slows down internet upload speed

[DJ Kulkarni]

Hi,

I have strange issue for cisco 8851 and 8861 when I use them connect to the switch port of phone the laptop internet speed is different

And when I connect the 7941 or 7961 phone it is quite good.Phones are in same vlan and auto qos is enabled

Switch is 3650 for the CUCM and 3550 switch is connected to the phone everything is wired

Firmware version on 8851  is 11-5-1-18

Regards,

DJ

[Andrew West]

Have you looked into the software versions on the switch ?

What about opening a TAC case?

[DJ Kulkarni]

Hi,

yes the software version is good latest one rebooted the switch but same issue

Checked the config setting on the phone all good.No Idea why that happens

Regards,

DJ

[Randall White]

Make sure the phone has negotiated 1000Mb/Full Duplex with both PC and Access Switch.

Check the phone's web page under Network and Access. While you are there, look for Collisions and some of the other packet errors. Next, check the Switchport and PC to make sure they agree with the phone on Speed and Duplex.

A couple of years ago, I had some problems with 8851s not negotiating 1000Mb with the switch. Upgrading switch firmware fixed the problem. I am also running 11-5-1-18 on my phones. I have a few locations where the cable plant won't allow me to run 1000Mb. In those cases, I manually set the phone to run 100/Full on both Network and Access ports.

Randall