3Com 3031 Command Reference Manual page 529

This command configures the synchronous serial interface to work in bidirectional
data simultaneous transmission mode. That is, the SDLC primary station can send
data to the secondary station and receive data at the same time.
Example
Configure the SDLC data to use the bidirectional transmission mode.
[3Com-Serial1/0/0] sdlc simultaneous
sdlc status
Syntax
sdlc status { primary | secondary }
undo sdlc status
View
Synchronous serial interface view
Parameter
primary: The primary station of the end, controlling the whole connection
process.
secondary: The secondary station of the end, controlled by the primary station.
Description
Using the sdlc role command, you can configure the SDLC role the device acts.
Using the undo sdlc role command, you can restore the default SDLC role.
By default, the device has no role.
The SDLC is a kind of link layer protocol in unbalanced mode. That is, the statuses
of the devices on the two connected ends are unequal: one is primary and the
other is secondary. The primary side, being the primary station, whose role is
primary, plays the dominant role and controls the whole connection process. While
the other side, being the secondary station, whose role is secondary, receives
control passively.
Therefore, the user needs to configure the role for the interface encapsulated with
SDLC protocol. On the SDLC role configuration, the roles should be decided by the
status of the SDLC device connected with the local router. If the SDLC device
connected with the local interface is primary, the local interface is to be set
secondary, and vice versa.
In general, the central IBM mainframe is primary, whereas terminal devices,
including UNIX hosts and ATM, are secondary.
Example
Configure the SDLC device connected with the Serial1/0/0 as primary, and the
local interface as secondary.
[3Com-Serial1/0/0] sdlc role secondary
sdlc timer ack
Syntax
sdlc timer ack mseconds
undo sdlc timer ack
DLSw Configuration Commands 529