Westermo MR Series - Manual (Page 229)

229 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
Confi gure > SNAIP > SNAIP n 4.76
The unit is capable of sending Systems Network Architecture (SNA) traffic over TCP/IP, using the
DLSw protocol. The unit is also capable of sending HDLC traffic over TCP/IP.
SNA uses Synchronous Data Link Control (SDLC) which is an unbalanced mode in which there
is one master station and 1 or more secondary stations. Each secondary station owns a station
address and can only respond when this address has just been polled by the master. A typical sce-
nario is shown in the diagram below:
Using the Web Page(s):
Description:
This parameter allows you to enter a name for this Ethernet instance, to make it easier to iden-
tify.
Layer 1 interface:
This parameter determines which physical interface is to be used for carrying SNAIP data. This
can be set to either “ISDN”, “Port” or “SharedPort”. If “ISDN” is selected then SNAIP data is
carried over the ISDN BRI physical interface. By selecting “Port”, SNAIP data can be routed to
either ASY 0 or ASY 1 (operating in synchronous mode), as selected by the Sync Port param-
eter below.
To configure ASY 0 or ASY 1 for synchronous operation refer to the Configure > Sync Ports
page.
If ”SharedPort” is selected, the ”l1nb” parameter specifies the SNAIP instance that has sync port
configured. When sync port sharing is enabled only one SNAIP instance can currently own the
sync port. This is determined by the success or otherwise of the DLSw exchange. When a
currently selected SNAIP instance goes down, a search is made based on the ”prio” setting and
the health of the DLSw connection to select another SNAIP instance to use.
The SNAIP parameter ”prio” this is used to select the SNAIP instance to use when more than
one is available; the highest number being given preference.
As an example consider that 4 SNAIP instances to all share sync port 0. To do this, configure
SNAIP 0 in the usual way on ”PORT 0” and then configure SNAIP instances 1,2 & 3 with the
”l1iface” set to ”SharedPort” and the ”l1nb” set to 0.
Shared priority:
This parameter is used to select the SNAIP instance to use when more than one is available; the
highest number being given preference.