According to David Byrd of Broadvox, agents and VAR's need more training when it comes to SIP. As he wrote in his Wild Mushroom post, "Too often we encounter a situation where an agent sells a SIP Trunk with no understanding of the difference between it and a PRI. This can lead to a disastrous situation. First, an agent needs to understand that the bandwidth require per phone call is more with G.711 not less than a PRI. Second, IP enabled equipment is required. This can be an IAD, IP PBX or, in the best case, the addition of an IP board or card. It is also very important to check the carrier’s interoperability IAD and IP PBX list."
Inter-Op and codecs are just a couple of things that Agents and VAR's need to learn. The world of TDM is defined by standards and pre-set configurations. The world of IP is wide open - no standards, just a bunch of specs that engineers and geeks tweek to get things to work. Being a Net-Head means a world of possibility, but it also means that pre-sales checking becomes paramount.
There are lots of places to get training. Alteva has a cert program that costs about $350, which includes sales and product training. As Byrd mentions, SIP School is around. MegaPath offers MPLS University. Avaya has a SIP for Dummies book. Almost every carrier has training on their product. I know that you get inundated with training webinars, but services today are not what you were selling five years ago. Take the time to take a few. Or lose out to other Agents who DO take the training - and become the Preferred Partners for the carriers.
Agents and VAR's can also test their knowledge with the TCA's Certified Telecom Professional certification program. The program includes subject material that can be reviewed before or after taking the exam. (Testers get 2 shots at getting a passing grade of 70.))