Sample transport resource list major node definitions

The following example shows transport resource list (TRL) major node definitions for the two hosts shown in Figure 1. Each TRL major node describes the transport characteristics of the multipath channel that is being used by the APPN host-to-host connection.

Figure 1. APPN host-to-host channel connection

A diagram that shows two VTAMs, A11N and A12N, that are connected by using a Type 2.1 channel.

LNCTL=MPC indicates that the link is a multipath channel-attachment link that can be used as an APPN host-to-host connection.

The READ operand specifies the subchannel addresses used to read data from the adjacent host. The WRITE operand specifies the subchannel addresses used to write data to the adjacent host.

For each subchannel address on the READ operand, the corresponding subchannel address is coded on the WRITE operand in the adjacent host to provide a complete path. The READ subchannel address and the corresponding WRITE subchannel address must reference the same physical connection between the two nodes, but the two addresses do not need to be identical. For example, node A11N can have a READ subchannel address of BC0, and node A12N can have a corresponding WRITE subchannel address of BD0 as long as A11N's BC0 is physically connected to A12N's BD0.

Although a pair of subchannel addresses is defined in this example, the subchannel addresses can be defined as a single address, a range of addresses, or both.

MAXBFRU=6 specifies that VTAM® uses six 4K buffer pages to receive data when activating the multipath channel.

REPLYTO=3.0 specifies that VTAM waits 3 seconds for completion of a multipath channel (MPC) XID I/O operation after starting a channel program. If this timeout expires, a message is written to inform the operator that a timeout has occurred.

***********************************************************************
* TRL Major Node for A11N                                             *
***********************************************************************
*************************************************
* TRANSPORT RESOURCE LIST MAJOR NODE FOR        *
* APPN HOST-TO-HOST CHANNEL.                    *
* LINE AND PU STATEMENTS AND A TG               *
* CODED SO THAT IT FLOWS OVER TWO SEPARATE      *
* CHANNELS (CHPID'S).                           *
*************************************************
MPCTRL  VBUILD TYPE=TRL,CONFGDS=CTC1011
* VIRTUAL CONNECTIONS USING TWO CHANNEL PATH IDS TO A12N
MPC1    TRLE   LNCTL=MPC,                                              X
               READ=(BC0,BE0),                                         X
               WRITE=(BC1,BE1),                                        X
               MAXBFRU=6,                                              X
               REPLYTO=3.0

***********************************************************************
* TRL Major Node for A12N                                             *
***********************************************************************
*************************************************
* TRANSPORT RESOURCE LIST MAJOR NODE FOR        *
* APPN HOST-TO-HOST CHANNEL.                    *
* LINE AND PU STATEMENTS AND A TG               *
* CODED SO THAT IT FLOWS OVER TWO SEPARATE      *
* CHANNELS (CHPID'S).                           *
*************************************************
MPCTRL  VBUILD TYPE=TRL,CONFGDS=CTC1011
* VIRTUAL CONNECTIONS USING TWO CHANNEL PATH IDS TO A11N
MPC1    TRLE   LNCTL=MPC,                                              X
               READ=(BC1,BE1),                                         X
               WRITE=(BC0,BE0),                                        X
               MAXBFRU=6,                                              X
               REPLYTO=3.0