Re: SIP trunking
Thanks for the question!
Benefits from SIP include the following:
Scale: You can scale up and down with SIP Trunking quickly. Need 20 additional call paths? If you have the bandwidth available, there isn't a delay to drop additional copper for traditional PRI service.
Flexibility: You can mix SIP solutions to meet business goals. Running a heavy outbound campaign? Use a Usaged based carrier for when you need the extra capacity, without impacting your inbound trunks.
Cost Savings: Use existing data connections to route voice calls and avoid copper line taxes. MPLS is a fantastic way to ensure data delivery on an existing network.
Advanced Features: DID anywhere, faxing, outbound call services, E911 and a vast array of carriers to select
Geo Diversity: Using SIP allows for easier failover if there is a single site failure or even device failure. Difficult to add redundancy to a PRI, easy in the SIP world.
SIP can add some complexity as it is an IP Service. Common mistakes I see are specifically around expectations or lack of experience with SIP and WAN technology by system administrators.
An overused internet connection with a 6 year old firewall is not conducive to great call quality. Also connections without any type of quality of service on their WAN connection will experience some sort of call quality issues due to internet traffic. Organizations that have high availably requirements will want to invest in a second, diverse internet connection.
Deploying a network monitoring solution and ACTIVLY monitoring your connections will help isolate issues when they arise and keep things working well. Lastly, working with a provider that has experience in deploying SIP will help ease these concerns and make it a successful project.