CCNA 新版（英文）D20S09L02.pps

© 2002, Cisco Systems, Inc. All rights reserved.
© 2002, Cisco Systems, Inc. All rights reserved.
2
Configuring Dial-on-Demand Routing
Objectives
pleting this lesson, you will be able to:
Configure legacy DDR, given a functioning remote access router and a physical ISDN connection
Use mands to identify the anomalies in the legacy DDR configurations, given a functioning remote access router and a physical ISDN connection
Use mands to identify the anomalies in the legacy DDR configurations, given a functioning remote access router and a physical ISDN connection
Connects when needed
Disconnects when finished
ISDN or PSTN
What Is Dial-on-Demand Routing?
When to Use DDR
Periodic connections
Small amounts of data
1. Route to destination is determined.
2. Interesting packets dictate DDR call.
3. Dialer information is looked up.
4. Traffic is transmitted.
5. Call is terminated.
Generic DDR Operation
3
1
2
Define static routes—What route do I use?
Specify interesting traffic—What traffic enables the link?
Configure the dialer information—What number do I call?
Configuring DDR
1
Defining Static Routes
dialer-list 1 protocol ip permit
dialer-list 1 protocol ip list 101
access-list 101 deny tcp any any eq ftp
access-list 101 deny tcp any any eq
access-list 101 permit ip any any
Any IP traffic will initiate the link without access lists.
Any IP traffic, except FTP and , will initiate the linking.
Using access lists gives finer control.
Denies FTP
Denies
Specifying Interesting Traffic
Applies rules defined by dialer-list to individual interfaces
hostname Home
!
isdn switch-type basic-5ess
!
username central password cisco
interface BRI0
ip address
encapsulation ppp
dialer idle-timeout 180
dialer map ip name Central 5552000
dialer-group 1
no fair-queue
ppp authentication chap
!
router work
!
no ip classless
ip route
ip route
!
dialer-list 1