IBM z/OS Communications Server

A high-performance foundation for building and deploying networking applications on z/OS

Get an overview

IBM z/OS® Communications Server provides a set of communications protocols that support peer-to-peer connectivity functions for both local and wide-area networks, including the most popular wide-area network, the Internet. It also provides performance enhancements that can benefit a variety of TCP/IP applications.

IBM z/OS Communications Server, a high availability enterprise transaction and data server, provides common applications, such as FTP, Telnet and the remote execution of applications. Built for optimum productivity, it provides a secure platform for developing and sharing mainframe workloads.

IBM z/OS Encryption Readiness Technology (zERT) Network Analyzer, a new z/OSMF plugin, is now available for you to easily query and analyze the cryptographic protection attributes of your z/OS TCP/IP and Enterprise Extender connections.

What's new

Updates and enhancements for z/OS 3.1 Communications Server

z/OS Communications Server performance summary reports

Benefits High-speed connectivity

Supports high-bandwidth and high-speed networking technologies, including Shared Memory Communications (SMC), which provides significant performance improvements for TCP protocol workloads.

High availability

Uses z/OS Parallel Sysplex® technology to enable high availability application support.

Network security

Protects sensitive data and the operation of the TCP/IP stack on z/OS.

IPv6 enablement

Enables IPv6, the successor to aging IPv4 technology, to handle the demands of internet usage with 128-bit addressing.

Network management

Collects network topology, status, and performance information.

Simplification and usability

Makes it faster and easier to configure policy-based networking functions by using Configuration Assistant.

z/OS Encryption Readiness Technology

zERT is an intelligent network security discovery and monitor feature of z/OS Communications Server. It is a core capability of IBM Z pervasive encryption.

IBM zERT Network Analyzer is a web-based interface on z/OSMF. It helps you determine which z/OS TCP and Enterprise Extender traffic is or isn’t protected according to specific query criteria.

With z/OS V2R5, zERT Policy-based Enforcement allows policy-based rules that describe different levels of cryptographic protection along with optional actions to take when TCP connections match those rules. With z/OS 3.1, IBM zERT Network Analyzer provides enhancements for database connection authentication, improved upgrade support, and a user interface refresh.

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Enhanced AT-TLS

AT-TLS (Application Transparent — Transport Layer Security) provides TLS encryption and decryption of TCP/IP connections based on policies created with the IBM Network Configuration Assistant. The z/OS sockets application sends and receives clear text (unencrypted) data as usual while AT-TLS applies TLS protection to the data at the TCP transport layer. With z/OS 3.1, AT-TLS supports several new System SSL features.

Explore the AT-TLS information hub

Enhanced network security

Get enhanced network security and compliance for more secure data transfer and higher productivity:

  • z/OS UNIX syslogd support for secure logging over TCP
  • FTP Server JES access control
  • SMF 1154 records for compliance evidence
Explore the security enhancements

Enhanced modernization and simplification

Get enhanced application modernization and simplified operating system management for optimized business operation:

  • Communications Server exploitation of the IBM Function Registry for z/OS
  • Support for 64-bit Java
Explore enhanced simplification Explore enhanced application development

Network support for z/OS Container Extensions

z/OS V2R4 Communications Server has added network support for z/OS Container Extensions which provides native z/OS support for Linux Docker based application workloads.

Network support for z/OS Container Extensions

Shared Memory Communications - Direct multiple IP subnet support (SMC-Dv2)

z/OS V2R4 Communications Server, with TCP/IP APAR PH22695 and SNA APAR OA59152, is enhanced to support SMC-Dv2. Unlike the original Shared Memory Communication - Direct Memory Access (SMC-D) protocol, SMC-Dv2 does not require that the communication peers reside within the same IP subnet.

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Shared Memory Communication - Remote multiple IP subnet support (SMC-Rv2)

In z/OS V2R5 Communications Server, SMC-Rv2 and IBM z15 with RoCE Express2 will support “routable RoCE” connectivity over multiple IP subnets for communications across IBM Z systems.

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Supports OSA-Express Enhanced Inbound Blocking and IBM RoCE Express3

z/OS V3R1 Communications Server is enhanced to support:

  • OSA-Express Enhanced Inbound Blocking (EIB). It is a QDIO performance enhancement that might be beneficial for OSA interfaces with a high volume of inbound network bulk or streaming traffic.
  • Shared Memory Communications over Remote Direct Memory Access (SMC-R) function to support the next generation IBM RoCE Express3 feature. The IBM RoCE Express3 feature allows TCP/IP stacks on different LPARs within the same central processor complex (CPC) to leverage the power of these state-of-the-art adapters to optimize network connectivity for mission critical workloads by using Shared Memory Communications technology.


Explore hardware support

Network management for IBM Cloud Provisioning and Management for z/OS

IBM Configuration Assistant for z/OS Communications Server plays a key role for the network administrator as part of the IBM Cloud Provisioning and Management for z/OS solution.

Explore Cloud Provisioning and Management for z/OS

TCP/IP usability enhancements in z/OS V2R5

z/OS V2R5 Communications Server provides the following TCP/IP usability enhancements to enable improved efficiency in system automation, the reduction of unwanted delays in system initialization, and improved certificate-related problem determination for AT-TLS and IPSec.

  - Notification of availability of TCP/IP extended services

  - AT-TLS and IPSec certificate diagnostics

  - IPSec certificate reporting enhancements

Get more technical information
New function APAR summary Version 3 release 1

Information on z/OS Communications Server new function APARs available for z/OS 3.1.

Version 2 release 5

Information on z/OS Communications Server new function APARs available for z/OS V2R5.

Version 2 release 4

Information on z/OS Communications Server new function APARs available for z/OS V2R4.

Related products IBM z16

The latest iteration of IBM Z® mainframes with on-chip AI inferencing and industry-first quantum-safe technologies.

IBM z/OS Parallel Sysplex

A feature of IBM z/OS that helps to boost server communications with clustering technology.

IBM z/OS Management Facility

A feature of IBM z/OS that allows communicating with and managing various aspects of a z/OS system through a web browser interface.

Next steps

Discover IBM z/OS Communications Server. Schedule a no-cost 30-minute meeting with an IBM Z and LinuxONE representative.

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