Managing communications quality over a SIP trunk
SIP trunk service is a rapidly growing public IP service where Internet Telephony Service Providers inject themselves between the enterprise VoIP deployment and the public switched telephone network. Gateways in the central office are generally more efficient and higher capacity than those deployed in the enterprise. The SIP trunk service reduces the number of PSTN connections into the enterprise office, relegating all outbound and inbound traffic through the enterprise Session Border Controller and ultimately to the IP-connected user. As an unregulated IP service, the SIP trunk attracts little or no tax or distance charges so it reduces cost and greatly improves enterprise numbering plan flexibility and total circuit capacity.
SIP trunk service extends the IP portion of the session far closer to Bob than to Alice. If Bob were in Vienna and Alice was in Chicago, the IP portion of the session would likely be all the way between Chicago and Vienna with the PSTN portion being only a local call in Vienna. This greater IP physical length introduces the need for unconventional SIP trunk quality management far beyond the limits of the IT organisation's typical sphere of control since the enterprise does not own the network of the ITSP and its global network of gateway service partners.
The SIP trunk service also allows for two enterprises to connect directly over VoIP without gateway or PSTN interaction, which facilitates the HD voice promise of IP phone vendors.
Standard WAN technologies for service management include traffic shaping, QoS and CoS. However, these capabilities do not provide end-to-end insight into the user experience and are therefore unable to manage demanding real time communications and the associated quality requirements. Instead, these tools are focussed on the network, packet queuing buffers, bandwidth prioritization and operational loads – necessary functions for network survivability and contract compliance, but not particularly useful in managing the user's SIP trunk experience.
Psytechnics benefits for SIP trunk deployments
Psytechnics offers particularly extensive features for managing services not normally in the control domain of ITSP tools, carrier management tools or enterprise QoS tools. Psytechnics customers have routinely used our technologies to diagnose persistent problems in ITSP networks that they do business with. Critical features include:
| • | Management of user experience, even over a SIP trunk, in real time |
| • | Detailed real time call visibility significantly reduces support costs since only experience-affecting problems engage engineering resources |
| • | Highly accurate problem diagnosis accelerates corrective action, reducing time-to-repair |
| • | Objective view of before-after service quality state strengthens negotiations at project signoff of new sites, services, infrastructures or site upgrades |
| • | Ability to pinpoint faults eliminates finger-pointing and trouble-ticket bouncing often associated with poorly equipped external service providers |
With Psytechnics Experience Manager solutions in place, common SIP trunk quality issues such as echo, distortion, noise, and varying volume levels – none of which are visible by typical WAN management tools – are rapidly identified and corrected, often before users experience is impacted.
