I have 5 sites connected with an SCN. They are networked with a Comcast layer-2 Ethernet service. Each site has a simple Cisco 1841 router. I can't seem to find a configuration with direct media path that ensures that all calls have working audio. When i forward calls from one store to another, the phone rings and connects but the audio is dead. The SCN is in a star configuration as per my installer, I also tried adding a line between the two sites in question and it did not correct things. Any ideas how to begin to debug this.