MTU Size for Comcast with Vocalocity VoIP Service

While working with Comcast tech support on Internet issues at a client’s site we were told to change the MTU size on the WAN interface of the client’s firewall to 1492. Comcast engineer claimed this setting will provide for fewer VoIP voice-quality issues with Comcast Internet services.

I thought I’d pass the information along to those who may be experiencing voice-quality issues with Internet-hosted VoIP services and have Comcast as their Internet Service Provider.

ISP: Comcast Business
Hosted VoIP Provider: Vocalocity / Vonage Business Solutions
Firewall: SonicWALL TZ200