I suspect that what would help more than VLAN would be QOS. Configure your ProCurve to prioritize voice traffic from the phones. VLAN can help with that, but it's not essential for that.
You might also try connecting one of the phones separately from the computer - by that I mean give the phone its own dedicated drop from the switch. See if that helps. What are your workstations doing, though, that would be saturating your pipe to the extent that your voice quality is poor? VoIP packets really aren't that big - on the order of 32kbps depending upon what codecs you're using. Have you tested the packet latency from the computer and/or the phone to the Allworx server? We recently deployed an Asterisk VoIP system for a client and have spent a little time troubleshooting sound quality issues. All of the phones at the local site to the server are brilliant (and no VLAN). The phones at one of their remote sites, connecting back to the server over IPSEC VPN, needed some help but I think we're on top of that problem now. Best wishes and aloha, Ben M. Schorr Chief Executive Officer ______________________________________________ Roland Schorr & Tower www.rolandschorr.com <http://www.rolandschorr.com/> [email protected] From: Evan Brastow [mailto:[email protected]] Sent: Thursday, December 17, 2009 1:40 PM To: NT System Admin Issues Subject: OT: VLAN question Preface: I have no idea what I'm talking about. With that out of the way, I have a network consultant and a phone supplier that are a little bit at odds. We just purchased an Allworx IP phone system. All was going well until it was made active today and because apparent that voice quality was horrible. The IP part is only internal... External calls go over standard analog lines. But the problem is with internal calls as well as external. The Allworx phones share a 100Mbps network with the computers. We're a small company (smaller than ever) with about 25 computers and 19 phones, BUT, a lot of those phones and computers are out in production areas and receive VERY little use (i.e., someone will log in/out of a job once every few hours, and make a phone call once a day out there.) There are probably only about 8-10 active computers, and fewer active phones. The way it's configured is that the phone sits on the same cable as the computer. It goes from the wall jack to the phone, and then from the phone to the computer. The phone are on the same subnet as, and get IP addresses from the same DHCP server as the computer network. When phone calls are made, there's echoing, latency, static, etc... The switch is an HP ProCurve 2810-48G. Cabling is all CAT5 at least. The phone supplier is telling me that the way to segment the traffic to make sure there are no voice quality issues is to create a VLAN on the switch. But my IT consultant is saying, "What's to segment? Everything's on the same cable and on the same subnet?" It appears now that the phone supplier is saying that he can create a VLAN, and then they would use the Allworx phone system server as a DHCP server for the phones, which would put them on their own subnet, thereby making all the traffic flow better and the calls clearer. He said he'd have to link the two VLANS together as there are computer apps that interface with the phone system. So, my question is (because I don't know much about this end of networking,) does this sound like creating a separate VLAN is really going to help improve bandwidth and increase call quality? Thanks so much J Evan ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
