Skinny Client Control Protocol
Encyclopedia
The Skinny Call Control Protocol (SCCP, or short Skinny) is a proprietary network terminal control protocol originally developed by Selsius Systems
.
The SCCP technology is now owned and defined by Cisco Systems, Inc.. SCCP is a lightweight protocol for session signaling with Cisco CallManager. Examples of SCCP clients include the Cisco 7900 series of IP phones, Cisco IP Communicator
softphone and the 802.11b wireless Cisco 7920
, along with Cisco Unity voicemail server. CallManager acts as a signaling proxy for call events initiated over other common protocols such as H.323
, Session Initiation Protocol
(SIP), ISDN and/or MGCP.
(RTP) over UDP
-transport for the bearer traffic (real-time audio stream) with other Skinny clients or an H.323 terminal. SCCP is a stimulus-based protocol and is designed as a communications protocol for hardware endpoints and other embedded systems, with significant CPU and memory constraints.
. Cisco also has marketed a Skinny-based softphone called Cisco IP Communicator.
, SocketIP, and Digium
have implemented this protocol in VoIP Terminals (phones), Media Gateway Controller
s, and Softswitch
es. An open source implementation is available in the Asterisk (PBX)
& FreeSWITCH
systems. IPBlue markets a software phone (soft phone) which uses SCCP for signaling and emulates a Cisco 7960 hardware phone. The Cisco Unified Application Environment, the product acquired by Cisco when they purchased Metreos
supports using SCCP to emulate Cisco 7960 hardware phones allowing applications to access all Cisco line-side features.
Selsius Systems
Selsius Systems was a telecommunications company in Dallas, Texas that developed and marketed some of the first IP telephony gear. It was co-founded by Richard Platt and David Tucker...
.
The SCCP technology is now owned and defined by Cisco Systems, Inc.. SCCP is a lightweight protocol for session signaling with Cisco CallManager. Examples of SCCP clients include the Cisco 7900 series of IP phones, Cisco IP Communicator
Cisco IP Communicator
Cisco IP Communicator is a VoIP softphone software application. It can register with a Cisco Unified Communications Manager or Cisco Unified Communications Manager Express using either SIP or Cisco's proprietary Skinny Client Control Protocol....
softphone and the 802.11b wireless Cisco 7920
Cisco Wireless IP Phone 7920
The Wireless IP Phone 7920 is a mobile phone branded by Cisco Systems, Inc. that communicates via IEEE 802.11b technology. According to C. Giancarlo, senior vice-president of switching, voice, and carrier systems at Cisco , the 7920 was not intended to replace traditional mobile phones...
, along with Cisco Unity voicemail server. CallManager acts as a signaling proxy for call events initiated over other common protocols such as H.323
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector that defines the protocols to provide audio-visual communication sessions on any packet network...
, Session Initiation Protocol
Session Initiation Protocol
The Session Initiation Protocol is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol . The protocol can be used for creating, modifying and terminating two-party or multiparty sessions...
(SIP), ISDN and/or MGCP.
Protocol components
A SCCP client uses TCP/IP to communicate with one or more Call Manager applications in a cluster. It uses the Real-time Transport ProtocolReal-time Transport Protocol
The Real-time Transport Protocol defines a standardized packet format for delivering audio and video over IP networks. RTP is used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications, television services and...
(RTP) over UDP
User Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...
-transport for the bearer traffic (real-time audio stream) with other Skinny clients or an H.323 terminal. SCCP is a stimulus-based protocol and is designed as a communications protocol for hardware endpoints and other embedded systems, with significant CPU and memory constraints.
Origin
Cisco acquired SCCP technology when it acquired Selsius Corporation in 1998. As a remnant of the Selsius origin of the current Cisco IP phones, the default device name format for registered Cisco phones with CallManager is SEP -- as in Selsius Ethernet Phone -- followed by the MAC addressMAC address
A Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet...
. Cisco also has marketed a Skinny-based softphone called Cisco IP Communicator.
Other implementations
Other companies like Symbol TechnologiesSymbol Technologies
Symbol Technologies is a manufacturer and worldwide supplier of mobile data capture and delivery equipment. The company specializes in barcode scanners, mobile computers, RFID systems and Wireless LAN infrastructure. Symbol Technologies is a wholly owned subsidiary of Motorola, and headquartered in...
, SocketIP, and Digium
Digium
Digium, Inc. is a privately held communications technology company based in Huntsville, Alabama. Digium specializes in developing and manufacturing communications hardware and telephony software, most notably the open-source telephony platform Asterisk....
have implemented this protocol in VoIP Terminals (phones), Media Gateway Controller
Media Gateway Controller
A Media Gateway Controller is a system used in certain Voice over IPtelephony architectures. An MGC controls a number of dumb terminals, the Media Gateways...
s, and Softswitch
Softswitch
A softswitch is a central device in a telecommunications network which connects telephone calls from one phone line to another, typically via the internet, entirely by means of software running on a general-purpose computer system...
es. An open source implementation is available in the Asterisk (PBX)
Asterisk (PBX)
Asterisk is a software implementation of a telephone private branch exchange ; it was created in 1999 by Mark Spencer of Digium. Like any PBX, it allows attached telephones to make calls to one another, and to connect to other telephone services including the public switched telephone network and...
& FreeSWITCH
Freeswitch
FreeSWITCH is a free and open source communications software for the creation of voice and messaging products. It is licensed under the Mozilla Public License , a free software license...
systems. IPBlue markets a software phone (soft phone) which uses SCCP for signaling and emulates a Cisco 7960 hardware phone. The Cisco Unified Application Environment, the product acquired by Cisco when they purchased Metreos
Metreos
Metreos was a software company that created and sold development and runtime tools for creating voice over Internet Protocol software applications. The company was founded by and Mark Richards and was based in the Austin, Texas, United States. On June 8, 2006 Cisco Systems announced that it was...
supports using SCCP to emulate Cisco 7960 hardware phones allowing applications to access all Cisco line-side features.