I've seen a few questions about this, but none have addressed the issue when dealing with a large number of users. I want to install a bandwidth shaping device that will ensure that we maintain high QoS for VoIP. It will be used for an office that currently has about 65 computer users. I have some potential solutions, but I'd like to hear some recommendations based on experience too. Thanks.

We use a Packeteer PacketShaper at my work. We have several hundred users and at least half of them have VoIP phones as well as PC's. Also, we do video conferencing (another service that requires QoS). The Packeteer works quite well.

Of course, we are using VLAN's and the VoIP is on it's own. We use separate PoE capable switches for the VoIP and do not mix data/VoIP on the same switch. Whenever possible, we have the VoIP switches on their own fibre uplinks to the core switches (separate fibre uplinks from the data switches in the same closets). We try to achieve as much separation between data and VoIP as possible prior to the streams hitting the Packeteer.

An alternative to Packeteer that's a good bit cheaper (no offense to Packeteer, we used one for years), is Netequalizer. I'm pretty sure that it works with VLAN now and has always been a good solution for VoIP QoS.