Assuming an organization has already implemented IP telephony and is running internal calls over their WAN via VoIP, the final step in moving to an all VoIP environment is to move to SIP trunking. Though SIP trunking may offer a significant cost savings opportunity on paper, the flawless implementation is key to overall success.
After the rate negotiations, contracts, design, and testing of SIP trunking have been completed, SIP trunking for outbound voice calls should be the first production implementation in the migration plan. The SIP trunks can be added to the environment with existing trunks left in place. All outbound calls would go over the SIP trunks, and the PSTN trunks would be used for overflow or if the SIP trunks fail. The advantages of this are:
* Lower costs--Take quick advantage of lower usage charges that SIP trunking offers for outbound calls (usually 25-50% less)
* Highly Available--Failover if the SIP trunks go down or have a problem, which will minimize service outages
* Low Security Risk--Outbound calling has fewer security challenges than in-bound calling via SIP trunking
* Easy to Implement--Not having to port numbers, 911 can still go over PSTN, advanced feature requirements are minimal, and users will not see any changes.
If SIP trunking is being implemented in a centralized model (out of a few data centers, which is recommended), the IP network infrastructure, SBC, SIP trunks, Service Provider, support/troubleshooting, reporting, and billing are all validated prior to a larger rollout.
As organizations look to deploy SIP trunking to lower their voice telecommunications expenses and further integrate voice into a unified communications strategy, outbound voice offers the best first production step.
For more details on "Implementing SIP Trunking," register for VoiceCon, where I will be presenting on this topic in detail and sharing best practices based on years of experience.
