Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90051)

184 Chapter9
Describing Asynchronous Devices
How to Access Multisessions
How to Access Multisessions
Multisession is the ability to have a device on a DTC simultaneously
associated with multiple sessions, jobs, or processes on one or more
hosts.
Each port can support up to 5 connections and connections can only be
active one at a time; the other connections are in a “hold” state. The
connection establishment method (Session or Programmatic, that is,
FOPEN) for multiple connections associated with a particular port is
determined by the first established connection. If this is a session then
the other multisession connections to that port must be session.
Similarly, if the first connection is established through the use of a
programmatic process, the other multisession connections must be
established through the use of a programmatic process.
Multisession is only available in a PC-based network environment (that
is, when the DTCs are managed by an OpenView Windows Workstation
on the LAN).
Multisession is supported on switched ports only and some restrictions
apply to nailed devices. See the list below:
Switched Ports: Multisession is supported only for switched ports.
Non Switched Ports: The DTC User Interface is not accessible to
non switched ports. For Multisession to establish another connection
it needs the DTC User Interface.
Nailed LDEV: If a switched port is configured as a nailed LDEV on
a system, then multiple sessions from that port to that system are
not possible because the port can have only the one connection
associated with the assigned LDEV on the host system. Although
multiple sessions to that particular host are not possible, it is
possible to establish multiple sessions from that switched port to
other systems.
Non Nailed LDEV: If a switched port is configured as a non nailed
LDEV on a system, then multiple sessions from that port to that
system are supported in addition to multiple sessions to multiple
systems.