My DSL upgrade saga took another step towards completion today, when Verizon installed a new phone line at home. Amazingly enough, it’s already in their DSL database, and Verizon’s DSL sales website allowed me to order DSL. I don’t have an install date for the DSL service yet, but I’m two steps closer to the finish line.
I was surprised that Verizon’s business DSL department gives you a choice of buying a new DSL modem ($99) or providing your own. I took the opportunity to order a Sangoma S518 PCI DSL card instead of an external box. Supposedly, their Linux drivers are solid (Sangoma has been involved with Linux practically forever), and there are a couple big advantages to native DSL interfaces, rather then DSL-to-Ethernet bridges. The biggest advantage is buffering–right now, my DSL modem has at least a couple seconds worth of buffers on it. If I send outbound traffic as fast as I can, I rapidly get to the point where nothing makes it out in under 2 seconds. So, even if I use extreme care in setting up QoS prioritization rules for VoIP traffic, the VoIP packets will still end up stuck in the DSL modem’s buffers. To combat this, I’ve been forced to rate-limit my outbound traffic to about 75% of the theoretical limit; even then it can really suck at times. Several people on Asterisk mailing lists have commented that their S518 has really made their VoIP performance shine.
In addition, since the S518 is directly talking to the phone company, it can tell exactly what speed I’m currently provisioned at and can log problems via syslog. My current nasty DSL box can’t do anything but blink lights at me when there’s a problem.
All in all, it looks like a decent improvement, especially since it’s only $115 or so online.