
Configuring Dial Services
1-18 114062 Rev. A
Bandwidth-on-demand is supported on asynchronous lines (RS449), synchronous
lines (RS449, V.35, RS422, and X.21) and on ISDN BRI and PRI interfaces.
Configure the leased and dial-up lines as follows:
• Leased line -- Any single leased line or multilink bundle.
Instead of a leased line it may be a switched dial-on-demand line.
Protocol supported: PPP multilink.
• Secondary dial-up lines -- Any WAN line including or ISDN B channels.
Protocol supported: Asynchronous or Synchronous PPP multilink.
The leased lines and secondary lines may operate at different speeds.
Figure 1-9 shows how secondary lines support a leased connection.
Figure 1-9. Bandwidth-on-Demand
Initially, the router brings up one secondary line to alleviate congestion. If
congestion persists, the router brings up a second and then a third line until the
congestion subsides. As each new line comes up, it becomes part of a bundle or
group of lines. The router then balances traffic over the bundle. Once the volume
of traffic decreases, the router brings down the secondary lines, one at a time.
Remote Site BCentral Site A
PPP Multilink (64 Kb/s)
Router
Router
ISDN
DS0006A
Key
Secondary Dial-up Lines
(ISDN B Channels)
Leased Line with
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