SIP-T21(P) E2 YEALINK IP PHONES IN THE NETWORK CREATE CONGESTION ON PORTS

[abhijit_roy]

Hi All,

      I am facing an issue in last couple of months, I have 4 no's of X440G2-48p-10G4 access switches in the network, one of the switch in the network got connected with above mentioned IP Phones like as follows due to scarcity of the physical port

 User End Port Connected to Internet port of IP Phone, and P.C Port of IP Phone connected to Desktops, I have observed that on those particular ports where IP Phones are connected facing port congestion issues,  and counters are incremental, and fluctuation in voice calls, for that for testing I have bypass the IP Phone and connect one to one like P.C to Switch and IP Phone to Switch, on that scenario I have observed port congestion in ports connected to IP Phone and there is no congestion in P.C Port, all the IP phones are apparently new.

So I was wondering if I have to enable any specific Protocol like lldp or anything else to avoid this scenario for access switches, and also please suggest about the recommended practice to connect IP Phones in the network.

[Gabriel_G]

Hello,

I would be suspicious of pause-frames from the VOIP phone causing this issue. Pause-frames are messages sent by an end device to tell a link-neighbor to slow down. This can in turn cause congestion for that port, especially if there is a work-station behind the VOIP phone.

To check for incoming pause-frames, check the command:

show port flow-control

In EXOS, you can tell the switch to ignore pause-frames with the following command:
disable flow-control rx-pause port <#>

Generally, ignoring pause-frames will not negatively impact the VOIP phone, but there may be a limitation of the VOIP phone as to how fast it can switch frames to the workstation.

Hope that helps!