1. Chapter 7
ISDN and DDR
第一單元
ISDN

2. What is ISDN? ISDN - Integrated Service Digital Network
Small Office
Digital PBX
Provider Network
Telecommuter
Home Office
Central Site
ISDN - Integrated Service Digital Network
Integrate Voice/Data/Video services

3. ISDN Standards Standards from the ITU-T (formerly CCITT) Issue
Protocol
Key Examples
Telephone network and ISDN
E.163—International telephone numbering plan E.164—International ISDN addressing
E-series
ISDN concepts, aspects, and interfaces
I.100 Series—Concepts, structures, terminology I.400—User-Network Interfaces (UNIs)
I-series
Q.921—LAPD (Link Access Procedure on the D channel) Q.931—ISDN network layer between terminal and switch
Switching and signaling
Q-series
Standards from the ITU-T (formerly CCITT)

4. Signaling information (LAPD)
ISDN Access Options
Channel
Capacity
Mostly Used For B
64 kbps
Circuit-switched data (HDLC, PPP) D
16/64 kbps
Signaling information (LAPD)
BRI
NT1
Service
Provider
Network 2B D
PRI
CSU/DSU
23B
or 30B D

5. ISDN 網路邏輯架構圖 ISDN Functions and Reference Points
Local Loop
TE1
Service Provider Network S
NT-2 T
NT-1 U
Native ISDN
TE2 R TA
Terminal
Adapter
Existing
Terminal
Functions are devices or hardware.
Reference points are demarcations or interfaces

6. ISDN BRI 網路實體連接圖 Native ISDN Interface - int bri 0 NT-1 TE1 S/T TE1 U
Service Provider Network
TE1
BRI 0
NT-1
S/T
BRI 0
TE1 U
NT-1

7. ISDN PRI 網路實體連接圖 Native ISDN Interface CSU CT1/ PRI-U CT1/ PRI CSU
Service Provider Network
CT1/
PRI-U
CSU
CT1/
PRI
CSU

8. Configuring ISDN BRI / PRI

9. ISDN Switch Types Many providers use many different switch typesCO S S S S CO
Many providers use many different switch types
Services vary by region and country

10. Configure ISDN BRI Step 1: Specify the ISDN switch type.
Router(config)#isdn switch-type switch-type
Router(config-if)#isdn switch-type switch-type
The command specifies the type of ISDN switch with which the router communicates. (例如: 歐規的 basic net3 或美規的 basic 5ess)

11. Configure ISDN BRI (cont.)
Step 2: (Optional) Setting SPIDs
Router(config-if)#isdn spid1 spid-number [ldn]
Slide 2 of 2
Purpose: This figure describes how to configure SPIDs.
Emphasize: The isdn spid1 and isdn spid2 commands are used on some switches and are replacements for subaddresses.
Some service providers require SPIDs to authenticate that a call requests are within contract specifications. SPIDs are required for National ISDN-1 and DMS-100 ISDN switches.
Some service providers require that both spid1 and spid2 be specified, while others only require spid1.
Sets a B channel SPID required by many service providers
Router(config-if)#isdn spid2 spid-number [ldn]
Sets a SPID for the second B channel

12. Configure ISDN PRI T1/E1 PRI Step 1: Specify the ISDN PRI switch type.
23B (T1) or 30B (E1) D
Step 1: Specify the ISDN PRI switch type.
Router(config)#isdn switch-type switch-type
Step 2: Select the T1/E1 controller.
Router(config)#controller {t1|e1} slot/port
Step 3: Set PRI group timeslots to function as PRI.
Router(config-controller)#pri-group timeslots range

13. ISDN PRI Examples T1 Sample Configuration E1 Sample Configuration
Router(config)#controller T1 3/0
Router(config-controller)#framing esf
Router(config-controller)#linecode b8zs
Router(config-controller)#pri-group timeslots 1-24
Router(config-controller)#interface Serial3/0:23
Router(config-if)#isdn switch-type primary-5ess
Router(config-if)#no cdp enable
E1 Sample Configuration
Router(config)#controller E1 3/0
Router(config-controller)# framing crc4
Router(config-controller)# linecode hdb3
Router(config-controller)# pri-group timeslots 1-31
Router(config-controller)#interface Serial3/0:15
Router(config-if)# isdn switch-type primary-net5
Router(config-if)# no cdp enable

14. Dial-on-Demand Routing (DDR)
第二單元
Dial-on-Demand Routing (DDR)

15. What is Dial-on-Demand Routing?
Dallas
Corporate
PSTN
Chicago
ISDN
I need to send
data to Dallas.
Connects when needed (自動撥號)
Disconnects when finished (自動斷線)
ISDN or PSTN

16. 使用 DDR 的時機? Periodic connections Small amounts of data Telecommuter
Headquarters
Periodic connections
Small amounts of data
Vendor

17. “Interesting” Packet Arrives
DDR 設定三部曲
“Interesting” Packet Arrives
Dial Connection
DCE
ISDN or PSTN
Define static routes — What route do I use? 1
Specify “interesting” traffic — What traffic enables the link? 2
Configure dialer information — What number do I call? 3

18. Step 1: Define Static Routes (What route do I use? )
Subnets
Subnet
ISDN
Home
Central
bri
bri 0
ip route
Specify Address of Next-Hop Router
ip route
ip route
Network Prefix
and Prefix Mask

19. Step 2: Specify Interesting Traffic (What traffic enables the link?)
dialer-list 1 protocol ip permit
Any IP traffic will initiate the link without access lists.
dialer-list 1 protocol ip list 101
access-list 101 deny tcp any any eq ftp
access-list 101 deny tcp any any eq telnet
access-list 101 permit ip any any
Deny FTP
Deny Telnet
Any IP traffic, except FTP and Telnet, will initiate the linking with access lists (for better control).

20. Step 2: Specify Interesting Traffic (cont.)
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
dialer-group 1
no fair-queue
ppp authentication chap
router rip
network
no ip classless
ip route
ip route
dialer-list 1 protocol ip permit
Applies rules defined by dialer-list to individual interfaces
Both Values Must Match

21. Step 3: Configure Dialer Information (what number do I call?)
How do I get to
subnetwork ?
Subnets
ISDN
Home
Central
bri
bri 0
interface BRI0
ip address
encapsulation ppp
dialer idle-timeout 180
dialer map ip name Central
dialer-group 1
no fair-queue
ppp authentication chap
Number to Dial
Remote Host Name
Used for PPP CHAP

22. Legacy DDR 設定總整理 3 1 2 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
dialer-group 1
no fair-queue
ppp authentication chap
no ip classless
ip route
ip route
dialer-list 1 protocol ip permit 3 1 2

23. Optional Legacy DDR Commands
Router(config-if)#dialer load-threshold load [outbound | inbound | either]
Establishes the amount of traffic on the link before a second B channel is enabled
Router(config-if)#dialer idle-timeout seconds
Establishes the idle time before disconnect

24. Legacy DDR Using ACLs Configuration Example
access-list 101 permit tcp any any eq smtp access-list 101 permit tcp any any eq telnet dialer-list 1 list 101 ! ip route ip route ! interface bri 0 ip address dialer-group 1 dialer map ip name B dialer idle-timeout 300
Access list defining interesting packets on Cisco A
Static routes to reach destination
Purpose: This figure explains how to use access control lists with DDR.
Interface configuration for DDR
Time to wait before dropping call
Subnets
ISDN A B

25. Verify Legacy DDR and ISDN Operation
Triggers a link (assuming it is part of interesting traffic)
Router#ping or telnet
Displays current status of link, including amount of time link is connected
Router#show dialer
When using ISDN, displays call status while call is in progress
Router#show isdn active
Displays the status of an ISDN connection
Router#show isdn status
Displays all routes, including static routes
Router#show ip route

26. Verify Legacy DDR and ISDN Operation (cont.)
Router#debug isdn q921
Shows ISDN Layer 2 messages
Router#debug isdn q931
Shows ISDN call setup and teardown activity
Shows call setup and teardown activity
Router#debug dialer
Clears currently established connections from the interface
Router(config-if)#shutdown