Cisco ROUTER-SDM-CD User Manual page 52

Additional Procedures
How Do I Configure Dial-on-Demand Routing for My ISDN or
Asynchronous Interface?
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Cisco Router and Security Device Manager 2.5 User's Guide
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ISDN BRI and asynchronous connections are dial-up connections, meaning that
in order to establish a connection, the router must dial a preconfigured phone
number. Because the cost of these types of connections is usually determined by
the amount of time that a connection was established, and in the case of an
asynchronous connection, that a phone line will be tied up, it is often desirable to
configure Dial-on-Demand Routing (DDR) for these connection types.
Cisco SDM can help you configure DDR by:
Letting you associate a rule (or ACL) with the connection, which causes the
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router to establish the connection only when it recognizes network traffic that
you have identified as interesting with the associated rule.
Setting idle timeouts, which cause the router to end a connection after a
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specified amount of time when there is no activity on the connection.
Enabling multilink PPP, which causes an ISDN BRI connection to use only
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one of the two B channels unless a specified percentage of bandwidth is
exceeded on the first B channel. This has the advantage of saving costs when
network traffic is low and the second B channel is not needed, but letting you
utilize the full bandwidth of your ISDN BRI connection when needed.
To configure DDR on an existing ISDN BRI or asynchronous connection:
Click Configure on the Cisco SDM toolbar.
Click Interfaces and Connections in the left frame.
Click the ISDN or asynchronous interface on which you want to configure DDR.
Click Edit.
The Connection tab appears.
Click Options.
The Edit Dialer Option dialog box appears.
If you want the router to establish the connection only when it recognizes specific
IP traffic, click the Filter traffic based on selected ACL radio button, and either
enter a rule (ACL) number that will identify which IP traffic should cause the
router to dial out, or click the ... button to browse the list of rules and choose the
rule that you want to use to identify IP traffic from that list.
Chapter 2 Creating a New Connection
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