ISDN and DDR
Objectives
• ISDN concepts
• ISDN configuration
• DDR configuration
Digital Communication with
ISDN
ISDN Benefits
ISDN Standards
ISDN Access Options
ISDN 3-Layer Model
Q.931 Messaging-Call Setup
Example
Call Processing
1. The D channel is used to send the called number to
the local ISDN switch.
2. The local switch uses the SS7 signaling protocol to
set up a path and pass the called number to the
remote ISDN switch.
3. The remote ISDN switch signals the destination over
the D channel.
4. The destination ISDN NT-1 device sends the remote
ISDN switch a call-connect message.
5. The remote ISDN switch uses SS7 to send a callconnect message to the local switch.
6. The local ISDN switch connects one B channel endto-end, leaving the other B channel available for a
new conversation or data transfer. Both B channels
can be used simultaneously.
ISDN Functions and Reference
Points
ISDN Functions and Reference
Points
BRI Reference Points
Cisco ISDN BRI Interfaces
ISDN Interfaces
S/T ISDN Interface
U ISDN Interface
ISDN Switch Types
Configuring ISDN BRI
Configuring ISDN BRI
Configuring ISDN PRI
Switch Types Available for
ISDN PRI Configuration
ISDN PRI Examples
Verifying ISDN Configuration
Troubleshooting ISDN
Configuration
DDR Operation
DDR Operation
Configuring Legacy DDR
Defining Static Routes
• When configuring static routes, consider
the following:
–By default, a static route will take precedence
over a dynamic route because of its lower
administrative distance. Without additional
configuration, a dynamic route to a network will
be ignored if a static route is present in the
routing table for the same network.
–To reduce the number of static route entries,
define a summarized or default static route
Specifying Interesting Traffic –
Dialer List
Configuring Dialer Information –
PPP
The dialer-group Command
The dialer-map Command
The dialer idle-timeout
Command
Dialer Profiles Overview
• Define encapsulation and access control lists
• Determine minimum or maximum calls
• Turn features on or off
Dialer Profile Elements
Configuring Dialer Interfaces
Verifying DDR
• show
• show
• show
• show
dialer
dialer interface [BRI]
isdn active
isdn status
Troubleshooting DDR
• debug isdn q921
• debug isdn q931
• debug dialer [events|packets]
• isdn call interface
• clear interface bri
Dialer Profiles
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Dialer profiles
• Legacy DDR powerful but can restrict growth
– Based on static binding between destination call
specification & a physical interface
• Locks physical interface into one configuration
• ‘dialer’ command configured on physical interface
– Rotary groups
• Single logical configuration from the dialer interface to
multiple physical interfaces
• Dialer profiles
– Dialer profiles – propagate logical configurations from
multiple dialer interfaces to a physical interface, as
needed – much more flexibilty
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Rotary Groups
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Dialer Profiles
• With dialer profiles, the logical and
physical configurations are dynamically
bound to each other on a per-call basis.
• This allows physical interfaces to
dynamically assume different
characteristics based on incoming or
outgoing calls, as shown in Figure Next
Slide
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Dialer profiles
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Dialer profiles
Interesting
traffic
dialer-list 5 protocol ip permit
map-class dialer ABC
dialer idle-timeout 30
…
interface dialer 0
ip add 192.168.x.x
dialer-group 5
dialer pool 1
…
dialer pool
interface dialer 1
ip add 172.16.x.x
dialer pool 1
dialer-group 5
dialer string 123 class ABC
…
interface bri 0
(Physical interface)
…
dialer pool-member 1
encap ppp
ppp authentication pap
…
interface bri 1
(Physical interface)
…
dialer pool-member 1
encap ppp
ppp authentication pap
…
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Labs
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Labs
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