Mainframe Networks - an Introduction

This two-day course introduces mainframe personnel to networks in a Z Systems environment. The course describes mainframe networks at a conceptual and terminological level, giving attendees a sufficient depth of detail to enable them to discuss issues relating to their organisation's networks with confidence and understanding.
The course introduces the important aspects of SNA, VTAM, APPN and TCP/IP, and explains their relationships. Attendees are also taught about the use of Console commands and how to use TSO commands to interrogate a TCP/IP network.
A number of practical, hands-on exercises are included throughout the course.

This course is available for exclusive, one-company presentations and for live presentation over the Internet, via RSM's Virtual Classroom Environment service.

What you will learn

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

  • understand the concepts of SNA/VTAM/APPN
  • understand and use the terminology of SSCP, CP, EN, NN. LEN, LU and PU
  • describe addressing in SNA/VTAM/APPN and TCP/IP
  • explain how TCP/IP fits into z/OS, especially for VTAM and TCP/IP applications.
  • stop and start VTAM, TCP/IP and TN3270
  • use the z/OS commands to interrogate a SNA/VTAM/APPN and TCP/IP network
  • use the TSO commands to interrogate a TCP/IP network (e.g. NETSTAT, PING, etc.)

Who Should Attend

Operators, Operations Analysts and others working in a z/OS based computing environment.


Familiarity with the z/OS environment and the ability to use TSO/ISPF.


2 days

Fee (per attendee)

£1250 (ex VAT)


This includes free online 24/7 access to course notes.


Hard copy course notes are available on request from

at £50.00 plus carriage per set.

Course Code



Introduction to SNA

What is SNA?; Pre-SNA networks; SNA hardware and software; SNA elements; Sessions; SNA layers; SNA message units; Session establishment sequence; Why APPN?; APPN node types; Resource registration; Resource location; LU-LU session activation; Locating resources.

Network Addressable Units

SNA Network Addressable Units (NAUs); SSCP/CP functions; PU types; Message flow; Address awareness; Subarea network addresses; APPN network address; Local addresses; Address conversion.

SNA Sessions

Sessions and half-sessions; half session layers; session types; setup flows; initiation sequences; logon request processing; LU-LU session types.

Console Commands

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

TCP/IP Overview

What is TCP/IP?; Why are we interested in TCP/IP?; What does TCP/IP comprise?; Internetworking principles; IPv4 addressing; IPv4 subnetting; IPv4 variable subnetting; Network Address Translation; One to One NAT; Network Address Port Translation (NAPT); TCP/IP protocol stack; IPv4 Address Resolution Protocol; IPv4 Dynamic Host Configuration Protocol; Why IPv6?; IPv6 addressing; IPv6 prefixes and address types; Global unicast address format; Anycast address; Multicast address; Required host information; Port numbers; IPv4 Transport Protocol message formats; IPv4 Internet Protocol: message format, packet format, header format; Extension Headers.

An Overview of TCP/IP on z/OS

TCP/IP for z/OS; TCP/IP access to SNA applications; How the gateway works; SNA access to TCP/IP applications; Communications Storage Manager ; Device connectivity and attachments; Direct vs indirect attachment; Direct attachment problem; Virtual IP addressing - the solution; Sharing attachments across LPARs; UNIX Systems Services considerations.

TCP/IP for z/OS - Command Overview

Available TCP/IP commands; The START and STOP commands; The MODIFY command; The DISPLAY command; The VARY command; The OBEYFILE command; The NETSTAT and onetstat commands; NETSTAT command options.

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