Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

IP phone acts as a switch or a hub?

My PC is attached to the IP Phone and the IP phone is connected to a 4006 switch. My PC is on a separate VLAN as the IP phone. Started sniffer on my PC to capture sent and received traffic on my PC's NIC. Surprised to see that the sniffer trace contained voice traffic also. Do that mean the IP phone acts as a hub instead of a switch?

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: IP phone acts as a switch or a hub?

That is correct. The IP phone is a hub.

5 REPLIES
Cisco Employee

Re: IP phone acts as a switch or a hub?

That is correct. The IP phone is a hub.

Cisco Employee

Re: IP phone acts as a switch or a hub?

This reply is incorrect. The current IP phones have a 3 port *switch* (aka C3PO), with one port internal. They support 802.1q, have 4 queues (1P3Q1T), and prioritize CoS 5 traffic (voice) over data. CoS 5 traffic goes into the priority queue, all other traffic goes into queues 1-3. The queues are scheduled in round-robin fashion with a priority queue timer to make sure priority traffic gets out.

You are seeing traffic out both ports since one of the design goals was to be able to dual-home the phone for very high-availability designs. Check out CSCdr32892

New Member

Re: IP phone acts as a switch or a hub?

Cannot locate CSCdr32892. Can you send me the URL or forward as an attachment?

Thanks..

Cisco Employee

Re: IP phone acts as a switch or a hub?

Sorry. This is not a bug, so is not posted. The pertinent text is:

"This works as designed. ...[Product design] specified that the

Telecaster MUST support "double homing" of its two links - allowing possible built-in "redundant" links for "very high availability" applications."

Cisco Employee

Re: IP phone acts as a switch or a hub?

There needs to be a correction to my last reply. The phone acts as a switch not a hub. Sorry for the confusion.

288
Views
0
Helpful
5
Replies
CreatePlease to create content