IBM CIP Protocols

Document ID: 17529

Contents

Introduction
Prerequisites
      Requirements
      Components Used
      Conventions
XCA Major Node
Switched Major Node
Subchannel and Path Configuration
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Introduction

The Cisco Systems Network Architecture (CSNA) implementation supports standard External Communication Adapter (XCA) configurations and switched major node configurations. For communication with the channel-attached 7000 router, no special configuration parameters or procedures are necessary in the Virtual Telecommunications Access Method (VTAM).

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

XCA Major Node

The IBM 3172 is transparent to VTAM because it cannot be addressed. The 3172 is not a physical unit (PU) like an IBM 3745/3756 or an IBM 3174. The 3172 is defined to the host control program, which can be multiple virtual storage (MVS) or virtual machine (VM), as a channel-to-channel machine, such as the 3088. This provides VTAM a physical connection out to the LAN through a subchannel.

Over this path, VTAM and LAN stations establish switched-like connections. This path is for one specific service access point (SAP), and for two or more VTAMs using different SAPs to share the LAN adapter.

A new major node type, the XCA, is introduced in VTAM V3R4 to support the physical connection. The XCA definition defines to VTAM all downstream Systems Network Architecture (SNA) resources attached to the LAN through the 3172. VTAM still provides the SNA routing, session, and data flows as it does under standard SNA environments.

Switched Major Node

SNA views PU Token Ring connectivity through the IBM Gateway Communication Controllers, such as IBM 3745 and IBM 3172, as switched or dial connections. VTAM on the SNA host defines switched connections using a VTAM switched major node. The switched major node identifies the Token Ring station PUs and their associated logical units (LUs). These can dial to the host mainframe or the host mainframe can call the station.

Both call-in and call-out are supported for the PU 2.0 and PU 2.1 SNA node types.

• Call-in support allows a node to initiate a Logical Link Control (LLC) connection by sending a TEST or exchange identification (XID) inbound to the mainframe.

• Call-out support allows the channel-attached mainframe to initiate an LLC connection with a LAN or WAN-attached node by sending a TEST outbound to the mainframe.

Subchannel and Path Configuration

For parallel channel connections, configuration information must be provided to determine which subchannels are used for CSNA.

For the Enterprise System Connection (ESCON) channel connections configuration, information must be provided to determine which paths, such as logical link address, logical partition (LPAR) number, coding unit (CU) logical number, and devices are used for CSNA.

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Related Information

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