Introduction to z/OS Communications Server

z/OS® Communications Server is a network communication access method. It provides both Systems Network Architecture (SNA) and Transmission Control Protocol/Internet Protocol (TCP/IP) networking protocols for z/OS.

The TCP/IP protocol suite (also called stack), includes associated applications, transport- and network-protocol layers, and connectivity and gateway functions. See z/OS Communications Server: IP Configuration Guide for more information about z/OS Communications Server IP protocols.

The SNA protocols are provided by VTAM® and include Subarea, Advanced Peer-to-Peer Networking (APPN), and High Performance Routing protocols. z/OS Communications Server provides the interface between application programs residing in a host processor, and resources residing in an SNA network; it also links peer users in the network. See z/OS Communications Server: SNA Network Implementation Guide for more information about z/OS Communications Server SNA protocols.

For the purposes of this library, the following descriptions apply:

The IBM® z Systems product line consists of the IBM z13 (z13).
The IBM zEnterprise® System (zEnterprise) product line consists of the IBM zEnterprise EC12 (zEC12), the IBM zEnterprise BC12 (zBC12), the IBM zEnterprise 196 (z196), and the IBM zEnterprise 114 (z114).
The IBM System z10™ product line includes IBM System z10 Enterprise Class (z10 EC) and the IBM System z10 Business Class (z10 BC).
The IBM System z9® product line includes IBM System z9 Enterprise Class (z9® EC) (formerly known as the IBM System z9 109 [z9-109]), and the IBM System z9 Business Class (z9 BC).
The IBM eServer™ zSeries product line includes the IBM eServer zSeries 990 (z990), and 890 (z890).
The IBM System 390 (S/390®) product line includes the IBM S/390 Parallel Enterprise Server Generation 5 (G5) and Generation 6 (G6), and the IBM S/390 Multiprise 3000 Enterprise Server.

The Start of change z13, End of change zEC12, zBC12, z196, z114, z10 EC, z10 BC, z9 EC (formerly z9-109), z9 BC, z990, and z890 servers are also known as z/Architecture® servers. z/OS V2R1 Communications Server runs only in z/Architecture mode on IBM z Systems, IBM zEnterprise, IBM System z10, and the IBM System z9 servers.