Session Initialization Protocol. Offers many of the same architectural features as H.323, but relies on IP-specific technologies such as DNS. It also incorporates the concept of fixed port numbers for all devices and allows for the use of proxy servers.


C21 Communications provides solutions and products designed to reduce the cost of telephony for SoHo and SME businesses, right through to global enterprises.

C21 Communications Ltd. Harwell International Business Centre, 173 Curie Avenue, Harwell, Didcot, Oxfordshire, OX11 0QG.


Contact Number: +44 1235 838592