Configuring SIP extensions has become one of the most requested support questions we receive. Asterisk, CISCO and ShoreTel all support SIP extensions. Candidly, SIP is an excellent protocol and one that most IT professionals are already familiar with. This is an application level protocol and looks an awful lot like HTTP etc. Ever go to a webpage and get a 404 error, “page not available”? Well SIP error messages are very similar. If you get a 404 SIP error message, it means phone not available. Though H323 and MGCP are certainly more mature protocols, they are most useful for “call processing”. SIP has the added dimension of being useful for presence information. Setting up SIP extensions on ShoreTel is a breeze and we have setup up everything from CISCO through Polycom desk phones and a handful of wireless handsets as well. ( I am working on getting my iphone connected to ShoreTel using a wireless SIP phone and I am breathlessly awaiting the release of 3.0). X-Lite makes a great SIP softphone on ShoreTel and I have included a soundless SIP configuration video for those of you familiar with ShoreTel administration. This configuration is built using cally the same in 8.1 so enjoy!Version 9 of ShoreTel, but it is basically the same in 8.1 so enjoy!