Cisco CP-7942G Administration Guide - Page 20

What Networking Protocols are Used? Chapter 1 An Overview of the Cisco Unified IP Phone Table 1-1 Supported Networking Protocols on the Cisco Unified IP Phone (continued) Networking Protocol Real-Time Control Protocol (RTCP) Session Description Protocol (SDP) Purpose Usage Notes RTCP works in conjunction with RTP to provide QoS data (such as jitter, latency, and round trip delay) on RTP streams. RTCP is disabled by default, but you can enable it on a per phone basis by using Cisco Unified Communications Manager. For more information, see the "Network Configuration Menu" section on page 4-24. SDP is the portion of the SIP protocol that determines which parameters are available during a connection between two endpoints. Conferences are established by using only the SDP capabilities that are supported by all endpoints in the conference. SDP capabilities, such as codec types, DTMF detection, and comfort noise, are normally configured on a global basis by Cisco Unified Communications Manager or Media Gateway in operation. Some SIP endpoints may allow these parameters to be configured on the endpoint itself. Session Initiation Protocol (SIP) SIP is the Internet Engineering Task Force (IETF) standard for multimedia conferencing over IP. SIP is an ASCII-based application-layer control protocol (defined in RFC 3261) that can be used to establish, maintain, and terminate calls between two or more endpoints. Like other VoIP protocols, SIP is designed to address the functions of signaling and session management within a packet telephony network. Signaling allows call information to be carried across network boundaries. Session management provides the ability to control the attributes of an end-to-end call. You can configure the Cisco Unified IP Phone to use either SIP or Skinny Client Control Protocol (SCCP). Skinny Client Control Protocol (SCCP) SCCP includes a messaging set that allows communications between call control servers and endpoint clients such as IP Phones. SCCP is proprietary to Cisco Systems. Cisco Unified IP Phones use SCCP for call control. You can configure the Cisco Unified IP Phone to use either SCCP or Session Initiation Protocol (SIP). Transmission Control Protocol (TCP) TCP is a connection-oriented transport protocol. Cisco Unified IP Phones use TCP to connect to Cisco Unified Communications Manager and to access XML services. Transport Layer Security TLS is a standard protocol for securing (TLS) and authenticating communications. When security is implemented, Cisco Unified IP Phones use the TLS protocol when securely registering with Cisco Unified Communications Manager. Trivial File Transfer Protocol (TFTP) TFTP allows you to transfer files over the network. On the Cisco Unified IP Phone, TFTP enables you to obtain a configuration file specific to the phone type. TFTP requires a TFTP server in your network, which can be automatically identified from the DHCP server. If you want a phone to use a TFTP server other than the one specified by the DHCP server, you must manually assign the IP address of the TFTP server by using the Network Configuration menu on the phone. User Datagram Protocol UDP is a connectionless messaging (UDP) protocol for delivery of data packets. Cisco Unified IP Phones transmit and receive RTP streams, which utilize UDP. Cisco Unified IP Phone 7962G and 7942G Administration Guide for Cisco Unified Communications Manager 7.0 1-6 OL-15483-01