Chapter 1 General Information
MX-2100/2104
Installation and Operation Manual
1-28 Application Considerations
When priority bumping is selected, the system administrator can define the critical
channels as high-priority channels. The high-priority channels can be assigned time
slots on either of the two links in accordance with system requirements.
Low-priority channels can then be added up to the maximum combined
bandwidth of the two links.
When the two main links operate at different data rates, it is possible to select
different priorities for switching, from link A to link B, and from link B to link A.
During normal operation, i.e., when both links are operational, all the channels are
carried by the assigned links. When one of the links fails, the high-priority channels
carried by the failed link are automatically switched over to the operational link.
When the management channel is carried by a main link time slot, it is always
handled as a high-priority channel.
Switched Backup Operation (not for MX-2104)
MX-2100 provides a switched backup mode of operation, that allows the use of
dial-up modems operating on low-cost switched data lines (PSTN mode) or ISDN
basic access lines as a backup to the main link (ISDN backup mode, based on the
use of the KML.10 main link module). MX-2100 allows flexible programming of
the switched backup option on a weekly basis. For each day of the week, it is
possible to define up to four different time periods, and to specify, for each
period, whether the use of the switched backup function is allowed.
The backup capabilities can be determined in two ways:
•
By entering the desired configuration in the alternate database stored by
MX-2100. This method allows the system administrator to freely select which
channels will be transmitted when the backup link is in use, and to specify for
these channels different data rates when using the backup link. Note that in
this mode the alternate database is dedicated to the backup link, so the
"day/night" configuration option cannot be used.
•
By defining the channels to be carried when the backup link is used as
high-priority channels. In this case, the channel data rates cannot be changed
with respect to normal operation, but the backup configuration is contained in
the on-line database. Therefore, it is possible to prepare "day/night"
configurations using the two MX-2100 databases.
Switched Backup Using Dial-up Modems
A typical PSTN switched backup configuration is shown in
configuration, one of the links is configured to carry the normal traffic, and the
other link is configured to serve as the backup link.
