瘦小客户端控制协议（SCCP：Cisco Skinny Client Control Protocol）是用于思科呼叫管理器及其 VOIP 电话之间的思科专有协议。有些供应商也支持该协议。
在 VOIP 解决方案中，要求 LAN 或者基于 IP 的 PBX 的终端机操作简单，易于上手且相对便宜。相对于 H.323 推荐的相当昂贵的系统，SCCP 定义了一个简单且易于使用的架构。通过 SCCP，H.323 代理可以与瘦客户机进行通信。在这样的情况下，电话充当了 IP 上的瘦客户机。代理服务主要用于 H.225 和 H.245 信令。
在 SCCP 结构中，大量的 H.323 处理任务就落在了称为 Cisco 呼叫管理器的 H.323 代理上。终端（电话）运行瘦客户端，这样该客户机只需消耗少量处理开销。客户机通过面向连接（基于 TCP/IP ）的方式与呼叫管理器通信，从而建立到另一个 H.323 兼容终端的呼叫。一旦呼叫管理器建立这个连接，那么两个 H.323 终端就可以通过无连接（基于 UDP/IP）通信方式实现音频传输。这样，通过限制从 H.323 到呼叫管理器建立呼叫的复杂性、以及为终端间的实际音频通信使用 Skinny 协议来降低整个过程的费用和负荷。
协议结构
瘦客户机（即一个以太网电话）使用 TCP/IP 传输和接收呼叫，并使用 RTP/UDP/IP 和其它客户机或 H.323 终端进行音频通信。瘦信息通过 TCP 端口 2000 传送。信息类型如下所示：
| Code | Station Message ID Message |
| 0x0000 | Keep Alive Message |
| 0x0001 | Station Register Message |
| 0x0002 | Station IP Port Message |
| 0x0003 | Station Key Pad Button Message |
| 0x0004 | Station Enbloc Call Message |
| 0x0005 | Station Stimulus Message |
| 0x0006 | Station Off Hook Message |
| 0x0007 | Station On Hook Message |
| 0x0008 | Station Hook Flash Message |
| 0x0009 | Station Forward Status Request Message |
| 0x11 | Station Media Port List Message |
| 0x 000A | Station Speed Dial Status Request Message |
| 0x000B | Station Line Status Request Message |
| 0x 000C | Station Configuration Status Request Message |
| 0x000D | Station Time Date Request Message |
| 0x000E | Station Button Template Request Message |
| 0x 000F | Station Version Request Message |
| 0x0010 | Station Capabilities Response Message |
| 0x0012 | Station Server Request Message |
| 0x0020 | Station Alarm Message |
| 0x0021 | Station Multicast Media Reception Ack Message |
| 0x0024 | Station Off Hook With Calling Party Number Message |
| 0x22 | Station Open Receive Channel Ack Message |
| 0x23 | Station Connection Statistics Response Message |
| 0x25 | Station Soft Key Template Request Message |
| 0x26 | Station Soft Key Set Request Message |
| 0x27 | Station Soft Key Event Message |
| 0x28 | Station Unregister Message |
| 0x0081 | Station Keep Alive Message |
| 0x0082 | Station Start Tone Message |
| 0x0083 | Station Stop Tone Message |
| 0x0085 | Station Set Ringer Message |
| 0x0086 | Station Set Lamp Message |
| 0x0087 | Station Set Hook Flash Detect Message |
| 0x0088 | Station Set Speaker Mode Message |
| 0x0089 | Station Set Microphone Mode Message |
| 0x 008A | Station Start Media Transmission |
| 0x008B | Station Stop Media Transmission |
| 0x 008F | Station Call Information Message |
| 0x009D | Station Register Reject Message |
| 0x 009F | Station Reset Message |
| 0x0090 | Station Forward Status Message |
| 0x0091 | Station Speed Dial Status Message |
| 0x0092 | Station Line Status Message |
| 0x0093 | Station Configuration Status Message |
| 0x0094 | Station Define Time & Date Message |
| 0x0095 | Station Start Session Transmission Message |
| 0x0096 | Station Stop Session Transmission Message |
| 0x0097 | Station Button Template Message |
| 0x0098 | Station Version Message |
| 0x0099 | Station Display Text Message |
| 0x 009A | Station Clear Display Message |
| 0x009B | Station Capabilities Request Message |
| 0x 009C | Station Enunciator Command Message |
| 0x009E | Station Server Respond Message |
| 0x0101 | Station Start Multicast Media Reception Message |
| 0x0102 | Station Start Multicast Media Transmission Message |
| 0x0103 | Station Stop Multicast Media Reception Message |
| 0x0104 | Station Stop Multicast Media Transmission Message |
| 0x105 | Station Open Receive Channel Message |
| 0x0106 | Station Close Receive Channel Message |
| 0x107 | Station Connection Statistics Request Message |
| 0x0108 | Station Soft Key Template Respond Message |
| 0x109 | Station Soft Key Set Respond Message |
| 0x0110 | Station Select Soft Keys Message |
| 0x0111 | Station Call State Message |
| 0x0112 | Station Display Prompt Message |
| 0x0113 | Station Clear Prompt Message |
| 0x0114 | Station Display Notify Message |
| 0x0115 | Station Clear Notify Message |
| 0x0116 | Station Activate Call Plane Message |
| 0x0117 | Station Deactivate Call Plane Message |
| 0x118 | Station Unregister Ack Message |
相关协议：RTP、RTSP、SIP、H.323、Megaco、H.248
组织来源：瘦小客户端控制协议（SCCP）是 Cisco 专有协议。