Skinny Client Control Protocol: Difference between revisions

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{{distinguish|Signalling Connection Control Part}}

'''SCCP''' is a proprietary terminal control protocol originally developed by Selsius Corporation. It is now owned and defined by [[Cisco Systems, Inc.]] as a messaging set between a skinny client and the Cisco [[CallManager]]. Examples of skinny clients include the Cisco 7900 series of IP phone such as the [[Cisco 7960]], [[Cisco 7940]] and the [[802.11b]] wireless [[Cisco 7920]]. Skinny is a lightweight protocol which allows for efficient communication with Cisco Call Manager. Call Manager acts as a signalling proxy for call events initiated over other common protocols such as [[H.323]], [[SIP]], [[ISDN]] and/or [[MGCP]].

The '''Skinny Client Control Protocol''' ('''SCCP''') is a proprietary network terminal control protocol originally developed by [[Selsius Systems]], which was acquired by [[Cisco Systems]] in 1998.

SCCP is a lightweight IP-based protocol for session signaling with Cisco Unified Communications Manager, formerly named ''CallManager''.<ref>{{cite web |url=http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_5_1/ccmsys/a08procl.pdf |archive-url=https://web.archive.org/web/20150711070711/http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_5_1/ccmsys/a08procl.pdf |archive-date=2015-07-11 |url-status=live|title=Understanding IP Telephony Protocols|publisher=}}</ref><ref>{{cite web|url=http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080624977.shtml|title=Call States Sent to SCCP Endpoints by Cisco CallManager|website=Cisco}}</ref> The protocol architecture is similar to the [[media gateway control protocol architecture]], in that is decomposes the function of media conversion in telecommunication for transmission via an [[Internet Protocol]] network into a relatively low-intelligence customer-premises device and a call agent implementation that controls the CPE via signaling commands. The call agent product is Cisco CallManager, which also performs as a signaling proxy for call events initiated over other common protocols such as [[H.323]], and [[Session Initiation Protocol]] (SIP) for [[voice over IP]], or [[ISDN]] for the [[public switched telephone network]].

A skinny client uses [[TCP/IP]] to and from one or more Call Managers in a cluster. [[Real-time Transport Protocol|RTP]]/[[User Datagram Protocol|UDP]]/IP is used to and from a similar skinny client or H.323 terminal for the bearer traffic (real-time audio stream). 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.

==Protocol components==

Cisco acquired SCCP technology when it acquired Selsius Corporation in the late 1990's. 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 address]].

AAn skinnySCCP client uses [[TCP/IP]] to andcommunicate fromwith one or more Call ManagersManager applications in a cluster. It uses the [[Real-time Transport Protocol|RTP]]/ (RTP) over [[User Datagram Protocol|UDP]]/IP-transport is used to and from a similar skinny client or H.323 terminal 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.

Some Cisco analog media gateways, such as the VG248 gateway, register and communicate with Cisco Unified Communications Manager using SCCP.

Other companies like [[Symbol Technologies]] and [[SocketIP]] have implemented this protocol in [[VoIP Terminal]]s (phones) and [[Media Gateway Controller]]s or [[Softswitch]]es.

==Origin==

A company named [http://www.ipblue.com/ IPBlue] has created a software phone ([[soft phone]]) which uses SCCP for signaling, too. This phone in fact appears to the Cisco [[CallManager]] server as a 7960 hardware phone.

Cisco acquired SCCP technology when it acquired Selsius Corporation in 1998.<ref>{{cite web|archiveurl=https://web.archive.org/web/20051109224815/http://newsroom.cisco.com/dlls/fspnisapi6d14.html|title=News @ Cisco: Cisco Systems to Acquire Selsius Systems, Inc. for $145 Million|archivedate=9 November 2005|publisher=|url=http://newsroom.cisco.com/dlls/fspnisapi6d14.html}}</ref> For this reason the protocol is also referred to in Cisco documentation as the Selsius Skinny Station Protocol. Another remnant of the origin of the Cisco IP phones is the default device name format for registered Cisco phones with CallManager. It is ''SEP'', as in ''Selsius Ethernet Phone'', followed by the [[MAC address]]. Cisco also has marketed a Skinny-based softphone called Cisco IP Communicator.

==Client examples==

In addition, Cisco has come out with its own version of a skinny softphone called Cisco Unified IP Communicator. Previously, Cisco had a JTAPI/CTI version of a softphone called Cisco IP Softphone.

[[File:Cisco CP7970.jpg|thumb|Cisco 7970]]

Examples of SCCP client devices include the Cisco 7900 series of IP phones, Cisco IP Communicator softphone, and the [[802.11b]] wireless Wireless IP Phone 7920, along with Cisco Unity voicemail server.

==Other implementations==

[[File:Cisco CP7911 Asterisk connected.jpg|thumb|[[Asterisk]] connected]]

Other companies, such as [[Symbol Technologies]], SocketIP, and [[Digium]], have implemented the protocol in VoIP terminals and IP phones, [[media gateway controller]]s, and [[softswitch]]es. An open source implementation of a call agent is available in the [[Asterisk (PBX)|Asterisk]] and [[FreeSWITCH]] systems.<ref>{{cite web|url=http://wiki.freeswitch.org/wiki/Mod_skinny|title=mod_skinny - FreeSWITCH - Confluence|website=wiki.freeswitch.org}}</ref> IPBlue provides a [[soft phone]] that emulates a Cisco 7960 telephone.<ref>http://www.ipblue.com/ IPBlue</ref> Twinlights Software distributes a soft phone implementation for [[Android (operating system)|Android]]-based devices.<ref>http://www.twinlightssoftware.com/ Twinlights Software</ref> The Cisco Unified Application Environment, the product acquired by Cisco when they purchased [[Metreos]], supports using SCCP to emulate Cisco 7960 phones allowing applications to access all Cisco line-side features.

==See also==

*[[de:SkinnyMedia ClientGateway Control Protocol]]

==References==

{{Reflist}}

[[Category:VoIP protocols]]

[[Category:Cisco protocols]]

[[Category:Application layer protocols]]

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