My home (Ethernet) network uses a D-Link DIR-825
router with a Motorola SB5100
to connect to the Internet via Comcast. Besides some switches used to distribute Ethernet throughout the house and within my home office, I have a VOIP device connected to the router that I use for work. My experience with that device has been great (plugged it in, flashed it, and it worked), but I was worried that I would not be able to get two VOIP devices to play nicely on my network.
router with a Motorola SB5100 to connect to the Internet via Comcast. Besides some switches used to distribute Ethernet throughout the house and within my home office, I have a VOIP device connected to the router that I use for work. My experience with that device has been great (plugged it in, flashed it, and it worked), but I was worried that I would not be able to get two VOIP devices to play nicely on my network.I signed up for Vonage through their web site, moving my land line phone number to the Vonage connection. It was 7 days before the number was moved.
Vonage provides a device they call V-Portal for free as part of establishing service with them. The installation instructions place this between the cable modem and existing router. I reluctantly proceeded this way and quickly discovered that the V-Portal includes an embedded router and firewall.
Within 15 minutes I had come upon a deal breaker. I use PPTP VPNs to connect to various networks for work. Going through my D-Link and the V-Portal, I was able to establish VPNs, but within 2-3 minutes the VPN was dropped. This is presumably a double-NAT issue, since data was traversing two routers.
My response was to reconfigure my setup to have my D-Link router connected to the cable modem with the V-Portal plugged into an Ethernet port off of that. My VPNs stopped dropping and the V-Portal still worked with my phone. The only negative of this configuration is that I had to connect a computer to the LAN port on the V-Portal to access the web management interface and enable management through the WAN, since the WAN interface on the V-Portal is the one that is accessible from my home network.
With the networking side appearing to work, I prepped the home phone network for Vonage. This simply meant disconnecting the network from the provider interface. In other words, I removed the cable coming from outside the house from the interior connection junction for my phones. This put all the phones in the house back in business.
One remaining problem slowly became apparent. During a call, audio on our side of the call would go dead for one to several seconds. The people to whom we were talking claimed no similar problem.
The most likely culprit seemed to be dropped outgoing packets. My initial cynical conclusion was that Comcast somehow determined these were Vonage VOIP packets and intentionally dropped them.
Looking for a solution within my reach, my attention turned to the D-Link router. It is a well regarded product with many features, any of which could be causing a problem. Browsing the options within the Advanced tab of the configuration application yielded many possible culprits and an equal number of promising options for a solution.
My first forays were changes to the WAN Shaping configuration, all with no efficacy. My attention then turned to the QOS engine. When I looked at Internet sessions, I could see that connections for both my work VOIP and Vonage devices had higher numerical priority values than other connections. Reading the on-line help indicated that lower numerical priority values were actually given higher priority. That sounded wrong (VOIP should have higher priority). I considered setting up a rule to force a lower numerical priority for Vonage, but instead simply disabled the QOS engine. Based on our experience since, that seemed to be the ticket: no more audio dropping during calls. Having QOS turned off has not adversely affected on-line Call Of Duty play in any noticeable way, either.
