Telenetics V.34-SDC - Manual (Page 84)

4-26 Configuring the Modem
C
onfiguring
th
e M
odem
Bandwidth On Demand
Bandwidth on demand is often required to support sporadic peak loads. With the
SDC modem, you can ensure full network availability and performance at low dial-
up line costs, without having to prioritize users or applications.
Figure 4-4 shows a point-to-point digital link with Telenetics 35XX DSU/CSUs
connecting two routers over a DDS circuit. The SDC modems are also connected
directly to the routers. During peak network access periods, the router is configured
to signal the SDC modem to establish a dial connection through the PSTN. Users
transparently bypass the digital link, using the 326XFAST-SDC PSTN link to
continue data transmission. As bandwidth demands subside, the dial call is dropped,
and transmission resumes over the DDS link.
The SDC modem supports all industry-standard ACUs (AT, V.25bis, DTR dialing,
and LPDA-2). Bandwidth on demand can be initiated/terminated under the control of
the nodal equipment by a secondary port. NOTE: Nodal equipment must be
configured for secondary port restoral/bandwidth on demand operation. Refer to the
nodal equipment documentation for instructions on configuring for this application.
Select SDC Option Set 3 for a bandwidth on demand application. All operational
information described in the preceding section, “SDC Option Set 3—Sync Dial
Only”, applies to this application.
Figure 4-4. Bandwidth On Demand—Option Set 3
35XX
56 kbps
PSTN
Router 35XX Router
To 33.6 kbps
NMS Network Management Channel
To
56 kbps
326XFAST
SDC
326XFAST
SDC