Troubleshooting SIP

Next Generation voice services are being delivered using SIP signalling. SIP based Voice over IP promises to reduce telephony costs and provides unique opportunities for integrating voice and Internet services. Voice services are being provided from SIP based telephones, soft phones and phone adaptors from customer premises over DSL access. SIP servers located within telecommunications service providers can deliver connectivity to external and international carriers but the telecom authority may not be the authority which deliver Internet services directly to the customer. In the event of failures in the services, technical staff need to be able to troubleshoot the voice services to discover the source of the fault locating it to customer premises equipment failure, configuration failures in customer equipment, failures within ISP service equipment or failures within the carrier voice services. Also increasingly customers are themselves implementing SIP based PBXs on their own site and wish to carry trunk connections using SIP between sites or into carrier services.

This course will provide an understanding of how to locate and troubleshoot faults within SIP based operational VoIP services. It will assume that the staff attending have already undergone initial training in the operation of the SIP signalling protocol for delivery of VoIP. It will, through practical hands-on workshops teach the SIP troubleshooting skills needed to recognise faults, locate them to the failing component and to fix these where that is feasible. The course will also provide an understanding of how SIP is being used between SIP based PBXs on customer sites acting as trunking paths to other SIP servers, both within the customer premises and within the carrier environment. It will also teach how this SIP trunking can be used for inter-carrier connection in the future. As ISDN based voice services declines, the voice features for call transfer, diversion, and other service features must be provided using SIP. The course will demonstrate how these key services may now be delivered using SIP and how to troubleshoot failures.

The course will use PC based protocol analysis software to isolate signalling faults and to reconstruct voice carried over the network in order to monitor voice quality. The course will address the different mechanisms used within IP and Ethernet protocols to deliver QoS and how QoS is affected by failures caused by incorrect sizing and network design at both the customer site and within the IP network delivered by the ISPs.