z/OS Communications Server Part 1 - SNA & VTAM

This two-day course introduces SNA at a conceptual and terminological level and teaches and explains the significant issues involved in VTAM installation and implementation. Attendees will learn how to define the network in order to optimize response time and throughput. Particular attention is paid to the implementation of VTAM network definitions in order to enable support of local and cross-domains.

This course is also available for one-company, on-site presentations and for live presentation over the Internet, via the Virtual Classroom Environment service.

Classroom dates (High Wycombe) - click to book!

29 July 2019 5 September 2019

Virtual Classroom Environment dates - click to book!

27 May 2019

What is a 'Virtual Classroom Environment'?


What do I need?

  • webcam
  • headphones with microphone
  • sufficient bandwidth, at least 1.5 Mb/s in each direction.


On successful completion of this course you will be able to:

  • define startup and session establishment procedures to the z/OS Communications Server (VTAM)
  • reinforce understanding of SNA architecture implementation
  • define network resources (major/minor nodes) to VTAM
  • avoid the most common mistakes made by new users
  • identify and code routing requirements for a VTAM network
  • code the definitions to support cross-domain communication
  • understand uses of VTAM console commands and communications controller hardware
  • describe various backup/recovery facilities.

Who Should Attend

All those who support VTAM based networks in any capacity will benefit from this course.


A knowledge of z/OS concepts. A basic understanding of network concepts would be helpful but is not mandatory.


2 days

Fee (per attendee)

£950 (ex VAT)

Course Code



SNA - Introduction

What is SNA?; Pre-SNA networks; SNA hardware and software; SNA elements; Sessions; SNA layers; SNA message units; Session establishment sequence.

Network Addressable Units

SNA NAUs; SSCP functions; CMC and Data Hosts; PU types; Message flow; Address awareness; VTAM & NCP network addresses; SNA network addresses; Sample network addresses; Local addresses; Address conversion..

Network Installation

Network planning; Network installation; MVS installation considerations; VM installation considerations; Network related data sets; VTAM start procedure; Structure of SYS1.VTAMLST; The ATCSTR00 member of SYS1.VTAMLST; The ATCCON00 member of SYS1.VTAMLST.

Network Definition

Major & minor nodes.

SNA Sessions

Sessions and half-sessions; Half-session layers; Session types; Logon request process; LU-LU session types.

Console Commands

The START command; The DISPLAY command; The VARY command; The MODIFY command; The HALT command.

SNA Resources

Applications and local terminals; Application programs; Local terminals; VTAM and application programs; The Application Major Node; TSO session establishment; VTAM and Local SNA terminals; The Local SNA Major Node; VTAM and Local non-SNA terminals; The Local non-SNA Major Node; VTAM and TCP/IP; The Application Major Node for TCP/IP.

User-Coded Tables

Assembled Tables; Unformatted System Services (USS) logon procedure; Mode Tables; USS Tables; USSCMD macro format; USSPARM macro format; SNA/SCS message 10 example; SNA character set; Non-SNA/3270 message 10 example; 3270 commands and orders.

Multi-Systems Networking Facility

MSNF terminology; Path control; Transmission groups; Explicit and virtual routes; The PATH statement; The Class of Service table (COS); Channel to Channel Adapters; Cross domain logon processing; Cross Domain Resource Managers; Dynamic CDRSC definitions; Cross Domain Resources; Adjacent SSCP Table.


Why APPN?; APPN node types; Resource registration; Resource location; LU-LU session activation; Locating resources; Route calculation; APPN Class Of Service; APPN COS definition in VTAM; APPN route setup; APPN routing; High Performance Routing; APPN/HPR and SNA; APPN/HPR message formats; ANR operation; RTP features; RTP path switching; APPN and Subarea SNA; APPN definitions in ATCSTR00.

What the students say

Very informative and useful. Pitched at a good level and explained clearly.

z/OS Systems Programmer

Barclays Bank plc

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