SAP - Novell's Service Advertising Protocol, provides information about what servers are available on the network.

SCCP - Signalling Connection Control Part, offers enhancements to MTP level 3 to provide connectionless and connection-oriented network services, as well as to address translation capabilities (SS7).

SCP - Session Control Protocol, manages logical links for DECnet connections.

SCSP - is a routine protocol in the TCP/IP family.

SCTP - Stream Control Transmission Protocol

SDP - Session Description Protocol

SDCP - PPP Serial Data Control Protocol, responsible for configuring, enabling and disabling the SDTP modules on both ends of the point-to-point link.

SDLC - Synchronous Data Link Control protocol, developed by IBM to be used as the layer 2 of the SNA hierarchical network.

SER - Serialization packet, ensures that a single version of NetWare is not being loaded on multiple servers.

SIP - SMDS Interface Protocol, three-level protocol that controls access to the network.

SIP (VoIP) - Session Initiation Protocol

SLP - Servise Location Protocol

SMB - Server Message Block, Microsoft presentation layer protocol providing file and print sharing functions for LAN Manager, Banyan VINES and other networking operating systems.

SMDS - Switched Multimegabit Data Service, broadband networking technology developed by Bellcore.

SMS - Short Message Service (UMTS)

SMS - Short Message Service

SMPP - Short Message Peer to Peer

SMTP - Simple Mail Transfer Protocol, mail service modeled on the FTP file transfer service (TCP/IP).

SNA - Systems Network Architecture, introduced by IBM to provide a framework for joining together many mutually incompatible IBM products for distributed processing.

SNACP - SNA PPP Control Protocol, responsible for configuring, enabling and disabling SNA on both ends of the point-point link (PPP).

SNMP - Simple Network Management Protocol, developed by the Internet community to allow diverse network objects to participate in a global network management architecture.

SOCKS - 

SPANS - Simple Protocol for ATM Network Signalling, developed by FORE Systems for use in ATM networks.

SPP - Sequenced Packet Protocol, provides a reliable virtual connection service for private connections (Banyan).

SPP - Sequenced Packet Protocol, provides reliable transport delivery with flow control (XNS).

SPX - Sequential Packet Exchange, Novell's version of Xerox SPP. It is a transport layer protocol providing a packet delivery service for third party applications.

SRB - Source Routing Bridging, proprietary header of Bay Networks which passes Token Ring information over WAN lines.

SRP - Spatial Reuse Protocol.           

SS7 - Signalling System 7, a common channel signalling system.

STP - Spanning Tree Protocol, prevents the formation of logical looping in the network (DECnet).