lec21 22 isdn lecture
DESCRIPTION
ISDN, good lectureTRANSCRIPT
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BROADBAND DIGITAL NETWORKSBy Engr. Awais Ahmed Khowaja
Mehran University of Engineering and Technology, Jamshoro.
01TL-BATCHThis class will meet: 8.00-10.00 a.m. (Mondays)
10.00-12.00 noon (Tuesdays)
Today's Lecture:ISDN
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Asynchronous Versus ISDN
• Analog converted to digital and back
Channelbank
Channelbank
SWSW SWSW
• Digital end-to-end
Channelbank
Channelbank
SWSW SWSW
The advantages of ISDN over analog connections include:
Higher speedFaster call setupCheaper than leased linesVoice and data can be run simultaneously
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ISDN Services and Channelized E1 and T1
56/64 kbps56/64 kbps
16 kbps
144 kbps
2B
D }{BRI
T1 1.544 Mbps
or
E1 2.048 Mbps (includes sync)
23B (T1) or30B (E1)
D
64 kbpseach
64 kbps}PRI
2.048 Mbps(includes sync)
31 64 kbpschannels }E1
1.544 Mbps(includes sync)
24DS0s }T1
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BRI Call Processing
ISDNservice provider
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B channel
D channel/SS7 signaling
2 SS7
Q.931 signaling Q.931 signaling
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TE1 NT1 LE
Local loop terminator
ISDN local exchange
ISDN terminal equipment
NT2
Customer premises switching equipment
TE2 TA
Non-ISDN terminal
equipment
Terminal adapter
S U
R
T
BRI Functional Groups and Reference Points
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Physical Representation of BRI Reference Points
Cisco ISDNrouter
To ISDNservice
Walljack
4-wirecircuit
2-wirecircuit
S/T UTA NT1NT1
S/T bus
S/T bus
S/T interface as a multipoint connection
To non-ISDNdevice (TE2)
R
ISDNphone
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PRI—Layer 1 Standards and Reference Points
LE
U
ITU-T I.431ANSI
T1.601
TE CSU/DSU
S/T
ITU-TI.430
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ISDN Protocol Layers
Layer 3
LAPD (Q.921)
D Channel B Channel
I.430/I.431/ANSI T1.601I.430/I.431/ANSI T1.601
HDLC/PPP/FR/LAPB
Layer 1
Layer 2
DSS1 (Q.931) IP/IPX
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ISDN
NT1
Daisy-chainS/T bus
TEI/SAPI
TEI/SAPI LE
ISDN Layer 2
–ITU-T Q.920 and Q.921–Defines logical link between TE/TA and NT2/LE–Carries Layer 3 D-channel messages
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ISDN Layer 3—D Channel Q.931
• Q.931 defines call control between the TE and local switch
TE ETNT1 LTQ.931
ISDN switch (LE)
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Q.931 Messaging—Call Setup Example
Callingparty
Calledparty
Setup
Connect acknowledge Connect
acknowledge
Setup
Setup acknowledge
Call proceeding
Alerting
Connect
Alerting
Connect
Call proceeding
Tim
e
ISDN service provider
ISDNswitch
ISDNswitch
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Q.931 Messaging—Call Teardown Example
Released
Disconnect
Calling party Called partyDisconnect
Released
Release complete
Release complete
Release
Tim
e
ISDN service provider
ISDNswitch
ISDNswitch
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DDR Operation
Interesting?
Connected?
Phone #?
Connected?
Dial
No
Yes
Yes
No
No
Send
Incoming packet
ResetIdle
TimerYes
NoInterface
up?
Yes
Yes
No
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Using DDR with ISDN
ISDN service provider
BRI or
PRI
1.
2. Remoterouter
1. Packet arrives2. Switch packet to DDR interface, determine if interesting 3. If interesting, dial DDR destination via ISDN 4. Connect to remote router
3.
4.
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ISDN Configuration Tasks
–Global configuration–Select switch type–Specify traffic to trigger DDR call
–Interface configuration–Select interface specifications–Configure ISDN addressing
–Optional feature configuration
ISDN
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ISDN Configuration Commands
–Set global parameters with this command:• isdn switch-type
–Set interface parameters with these commands:• encapsulation ppp
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Router(config)#isdn switch-type switch-typeRouter(config)#isdn switch-type switch-type
Router(config-if)#isdn switch-type switch-typeRouter(config-if)#isdn switch-type switch-type
Selecting the ISDN Switch Type
–Specifies the type of ISDN switch with which the router communicates
–Global or interface command
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Setting Interface Protocols
Router(config-if)#encapsulation {ppp | hdlc}Router(config-if)#encapsulation {ppp | hdlc}
• Selects framing for that ISDN BRI
Router(config-if)#ppp authentication {pap | chap | ms-chap}
Router(config-if)#ppp authentication {pap | chap | ms-chap}
• Selects PPP authentication type
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DDR Configuration Tasks
1. Define interesting traffic2. Assign interesting traffic definition
to ISDN interface 3. Define destination 4. Define call parameters
ISDNserviceprovider
BRI or
PRIRemoterouter
Interesting traffic arrives
Dial destination
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Defining Interesting Traffic
Router(config)#dialer-list dialer-group-numberprotocol protocol-name {permit | deny} list access-list-number
Router(config)#dialer-list dialer-group-numberprotocol protocol-name {permit | deny} list access-list-number
• Defines interesting packets for DDR • Associated with the dialer group assigned to the interface
Router(config-if)#dialer-group group-number Router(config-if)#dialer-group group-number
• Assigns an interface to the dialer access group specified in the dialer-list command
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