Time to take a SIP?
The latest buzz word in the comms industry is SIP trunking and I know from the feedback we get from customers that there’s a lot of interest in SIP trunks coupled with some very scanty knowledge, so I’ll try to put some light on the subject.
Basically a SIP trunk runs voice communications from a customer’s premises to the local exchange using a broadband link, instead of a conventional ISDN channel. The chief advantage is cost, because a SIP trunk is typically a third less expensive than the monthly rental cost of an equivalent ISDN service. But before you rush out and order up a SIP trunk solution there are some important factors to consider.
The main one is Quality of Service levels. Most ISPs provide broadband, even for business use, on a best-endeavour basis without any guarantees regarding service uptime. This is fine if you don’t mind losing your Internet connection for 20 minutes, but totally unacceptable if your SIP trunk link crashes while you’re speaking about a major deal to a new customer.
To overcome this challenges a new group of Internet Telephony Service Providers (ITSP) now offers uncontended DSL broadband links with service level agreements that provide guarantees of business class service for SIP trunks. But this is not the only issue for SIP trunk use.
There are also interoperability issues with customer premises equipment. There is no standard SIP trunk service so there can be interoperability issues regarding operation with existing phone systems and other hardware. System conflicts have a nasty habit of becoming apparent only in live operation!