Multipath channel connection

Multipath channel (MPC) allows you to code a single transmission group for host-to-host communication that uses multiple write-direction, read-direction subchannels, as illustrated in Figure 1.

Figure 1. Two multipath channel connections

A diagram that shows two nodes connected by 2 multipath channel connections consisting of multiple write-direction and read-direction subchannels.

There are multiple advantages to using MPC:

Because each subchannel operates in only one direction, the half-duplex turnaround time that occurs with other channel-to-channel connections is reduced.
If you code a transmission group in which the subchannels are divided between two physical channels, you can increase availability because the transmission group will have a path to use even if one physical channel is down.
Because each transmission group can use more than one channel, and because the turnaround time required for half-duplex is reduced, throughput is increased.

APPN host-to-host channel connections enable two VTAMs to communicate using APPN protocols over MPC connections. APPN host-to-host channel connection support requires the definition of transport resource list major nodes and local SNA major nodes, rather than channel-attachment major nodes. For more information about APPN host-to-host channel connection, see Transport resource list major node and APPN host-to-host channel connection.

To define MPC support, code the following definition statements:

VBUILD TYPE=CA
GROUP LNCTL=MPC
LINE
PU

Code only one LINE definition statement for multipath channel support. The subchannels on the physical channel are represented by the subchannel addresses coded on the READ and WRITE operands on this statement. One READ subchannel in one host and the corresponding WRITE subchannel in the other host form a complete path. In the two sample definitions that follow, note that the subchannel read addresses in one definition deck match the subchannel write addresses in the other.

Code one PU definition statement for the LINE definition statement.