I have three Dell switches in two different buildings. A powerconnect 3424, 2848, 5224. The 5224 and 2848 are connected via a fiber link. The 3424 is connected via a gigabit port on the 5224. They are upstairs from each other. There is only one other switch on the network, a small 5 port netgear gigabit switch (that I have taken out to troubleshoot with no difference). Here is the problem. We just switched to a VOIP system. We have Broadview Networks and Mitel phones. Maybe 35 phones. We have 50mb/10mb bandwidth and that is fine. The system works great when we call out to a phone number or someone calls in. When we dial an internal extension, sometimes the audio is only one way and one person cannot hear. If we hangup and keep trying, after 4 times or so, it will work. I was told this is likely a switch issue. All my switches have IP's so I can manage them, but nothing has been setup. They are default configs. We also have a sonicwall pro 3060 between the cable modem and our network. Can someone help with this? I heard perhaps creating VLANS, but I do not know how. I need someone to help!