WAN Restoral Configuration
Figure 37shows how you can use an ISDN connection to back up a failed
dedicated WAN link (WAN restoral). In this example, RouterA normally uses the
WAN link to communicate with Router B. If that connection fails, the ISDN dial-up
link reconnects the two routers. When the WAN link recovers, the secondary link
automatically disconnects. For more information on how to configure the router for
WAN restoral, see Using WAN Restoral in
Using and Configuring Features
.
For WAN Restoral, only dial circuits configured for PPP can be used as the
secondary link. For WAN Reroute, either a PPP dial circuit or a FR dial circuit can
be used as the alternate link.
Channelized T1/E1
When configured for channelized, the Channelized/PRI adapter allows you to get
Fractional/Channelized T1/J1/E1 support. Youcan have channels of 56-Kbps or
N*64-Kbps. This will let you multiplex multiple leased lines connections (for
example: using V.35at 56-Kbps) into one physical connection.
Toconfigure a T1 or E1 Primary adapter as channelized:
1. Select “Channelized” as the switch variant for the ISDN interface.
2. Configure the time slots to be used for this ISDN interface when you configure
the dial circuit. See “Set” on page646 for more information.
Example of configuring a Channelized T1 interface:
Config>n6
ISDN Config>set switch chan
ISDN Config>list
ISDN Configuration
Maximum frame size in bytes = 2048
Switch Variant/Service Type = Channelized
Available Timeslots:123456789101112131415161718192021222324
Config>n7
I
S
D
N
I
S
D
N
Dial
Circuit Dial
Circuit
Router A Router B
ISDN
WAN link
ISDN
backup link
Figure 37. Using ISDN for WANRestoral
Using ISDN
Chapter45. Using the ISDN Interface 617