Chapter 10 vN.1
Transcript of Chapter 10 vN.1
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ISDN Configuration
Chapter 10
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Chapter 9 2
Chapter Objectives
Explain ISDN features
Explain ISDN devices
Explain ISDN connections
Configure BRI
Configure PRI
Verify ISDN Connections
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Chapter 9 3
Recall
WAN is a network that spans a large geographical
area
Data-Link layer protocols are commonly called the
data link protocols, which communicate between two
devices
PAP is a insecure protocol because the username
and password is sent in plain text
Use debug ppp authentication to troubleshoot PPP Using CHAP protocol the server sends challenge
messages to the node. The node calculates and
sends the results back to the server
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Chapter 9 4
ISDN Features
ISDN provides Wide Area Network (WAN) services
in incremental values of 64 kbps
The features ofISDN are:
Speed
Multiple Device Support
Inexpensive
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Chapter 9 5
ISDN Channels and Services
ISDN network transmits information through the
three logical digital communication channels such as
Bearer (B) channel, Data (D) channel and Hybrid (H)
channel
H channel can be implemented as H0, H10, H11,
H12
ISDN supports two types of connections such as the
Basic Rate Interface (BRI) and Primary Rate
Interface (PRI)
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Chapter 9 6
ISDN Devices
The ISDN devices are given as follows:
Network Termination Device 1 (NT1)
Network Termination Device 2 (NT2)
ISDN Router Terminal Equipment 1 (TE1)
Terminal Equipment 2 (TE2)
Terminal Adapter (TA)
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Chapter 9 7
ISDN Connections
ISDN is a channelized service
A channelized service splits a wire into many logical
channels or time slots
Some of the common terms that are used inchannelized connections are:
Digital Signal 0 (DS0)
Digital Signal 1 (DS1)
T1 E1
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Chapter 9 8
ISDN Devices and Reference Points
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Chapter 9 9
ISDN Protocols
The following are ISDN protocols dealing with certainissues:
Protocols with E as the beginning letter deal with using
ISDN on the existing telephone lines
Protocols with I as the beginning letter deal with ISDNconcepts, aspects and services
Protocols with Q as the beginning letter deal with
switching and signaling. These protocols allow you to
connect to the ISDN and troubleshoot the network.The Q protocols include the following:
Q.921
Q.931
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Chapter 9 10
Switch Types and Connections - I
Switch Type Connection Type
basic-5ess BRI
basic-dms100 BRI
basic-ni1 BRIbasic-ni2 BRI
basic-1tr6 BRI
basic-net3 BRI
basic-nwnet3 BRI
basic-nznet3 BRI
basic-ts013 BRI
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Chapter 9 11
Switch Types and Connections - II
ntt BRI
vn2 BRI
vn3 BRI
vn4 BRI
vn5 BRI
pri-4ess PRI
pri-5ess PRI
pri-dms100 PRI
pri-nt PRI
pri-net5 PRI
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Chapter 9 12
Selecting Router ISDN Interface
To select a Cisco router with the correct ISDN
interface:
Check whether the router supports ISDN BRI
Identify the NT1 provider. NT1 ends the local loopto the Central Office (CO) of the service provider
Check whetherNT1 is Customer Premises
Equipment (CPE)
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Chapter 9 13
ISDN Call Setup Procedure
To set up an ISDN call between the router and the
ISDN switch, the D channel is used whereas,
between the switches within the service providers
network, Signaling System 7 (SS7) is used
By default, the D channel is always enabled
During the ISDN call, the calling host sends a call
setup request
Before the actual connection is established, manydifferent messages are sent across such as
progress messages and alert messages
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Chapter 9 14
Configuring BRI
You can configure the BRI for the router after
connecting the ISDN equipment
The generic steps to configure BRI are:
Setting an user name and password
Setting the switch type
Configuring ISDN interface on a router
Setting the Service Profile Identifier (SPID)
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Chapter 9 15
Setting the SPID
Service Profile IDentifier (SPID) is a set of numbers
for BRI connections that have a National ISDN-1 or
Nortel DMS-100 switch
The SPID consists of the ten-digit telephone number
for the connection and extra identification digits
The SPIDs are provided along with the switch carrier
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Chapter 9 16
Configuring PRI - I
You need to configure additional parameters for PRIon your router
After setting the switch type, you need to configure
the T1/E1 controller card and the serial interface of
the controller card The different configuration settings for the controller
card include:
Framing
Line code
Clock source
Timeslots
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Chapter 9 17
Configuring PRI - II
The generic steps to configure PRI are:
Setting the ISDN switch type with which the router
will communicate
Selecting the controller and specifying the type(T1/E1), framing type and line coding for the
provider
Setting the port to function as PRI and specifying
the PRI
slot for T1 or E1 and the speed
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Chapter 9 18
Verifying ISDN Connections
After configuring the interfaces, you need to verify
that they have been configured properly
You can verify the ISDN connections using two
commands
show interface command
show isdn status command
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Chapter 9 19
ISDN Verification Commands - I
Command Description
ping and telnet Enables you to ping or telnet the remote router
when the link is established without
considering the interesting traffic listshow dialer Provides dialer information that includes status
of the link, idle time, length of the call, router to
which the interface is connected
show isdn active Displays the phone number and whether the
call is active
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Chapter 9 20
ISDN Verification Commands - II
show isdn status Displays the detailed status of the ISDN
interfaces
show ip route Displays all the routes of the router
debug isdn q921 Enables you to view layer 2 information
debug isdn q931 Enables you to view layer 3 information
debug dialer Provides the call setup and disabled activities
isdn disconnect interface bri 0 Enables you to clear the interface and
disconnect the connection
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Chapter 9 21
Dial on Demand Routing
Cisco provides Dial on Demand Routing (DDR)
feature that allows the Cisco router to dial an ISDN
when it receives an interesting traffic
The interesting traffic is referred as IP traffic fulfilling
specific criteria such as particular protocol and
highly secured destination address
If a traffic using particular criterion is set as
interesting traffic, the traffic is given the highest
priority during the transmission
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Chapter 9 22
Making a phone connection - I
To make a phone connection, the DDR goes through the
following process:
When a packet is received, the router checks the
routing table to locate the destination
The router determines if the packet is interesting.
The router establishes DDR connection by dialing the
ISDN. When the received packet is interesting and the
DDR is not active, the router makes a phone call to
establish connection. If the received packet is notinteresting and the DDR is not active, the router drops
the packet. However, the router transmits all the
packets if the DDR already active
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Chapter 9 23
Making a phone connection - II
Once the connection is established, the router
transmits the packets from the DDR interface
The router terminates the connection if no packets
are to be transmitted or the connection remains
idle for certain period
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Chapter 9 24
DDR Configuration - I
You can allow the Cisco router to perform the DDR
process by configuring it
DDR can be used in the following situations:
The telecommuters need to connect to thecompany network periodically
There are offices that need to send transactions
or requests to the main computer at the central
office
The users need to retrieve the e-mail from the ISP
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Chapter 9 25
DDR Configuration - II
The generic steps to configure legacy DDR are:
Configuring static routes that are the routes for
remote networks
Specifying which traffic is interesting
Activating dialer list that contains the information
about the traffic that can generate calls
Configuring a dialer map that informs the router to
make a call using legacy DDR
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Chapter 9 26
Configuring Static Routes
The DDR feature of Cisco allows you to prevent
unwanted traffic from making phone calls and
keeping the line busy
configuring static routes helps in avoiding other
traffic to trigger calls
The ip route command enables you to define the
static route. The syntax of this command is:
ip route network_IP_address_# subnet_mask
remote_routers_IP_address|router_interface
[administrative_distance]
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Chapter 9 27
Specifying Interesting Traffic
Access Lists (ACLs) allows you to specify the
interesting traffic on the router
Using the dialer-list command, you can allow only
the IP traffic to establish connection
The dialer-list command enables you to specify
which traffic is interesting. The syntax of this
command is:
dialer-list [list_#] protocol [protocol_name]
permit|deny access-list [ACL_#]
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Chapter 9 28
Activating Dialer List
You need to activate the dialer list on the DDR
interface after the list is created
It is necessary to activate the list because the list is
not an ACL and it only specifies which traffic is
interesting traffic by referring an ACL
To activate the dialer list, you should use the dialer-
group command. The syntax of this command is
given as follows:
dialer-group dialer_list_#
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Chapter 9 29
Configuring Dialer Maps
Once you finish specifying the interesting traffic and
activating the dialer list on the DDR interface, you
can specify dialer information to the router
The dialer map command gives dialer information
for the router to make phone calls. The syntax of the
command is:
dialer map protocol_name
destination_router_address name [remote_router]
speed [56|64] [broadcast]
[destination_phone_number]
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Chapter 9 30
Dialer Profiles
With the help of dialer profiles, the following tasks
can be performed:
Configuring B channels with different IP subnets
Using encapsulation on the B channel Setting DDR parameters for the B channels
Eliminating the garbage ofISDN B channels by
allowing ISDN BRI interfaces to associate with
multiple dialer pools
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Chapter 9 31
Configuring Dialer Profiles
You can configure many dialer interfaces on the
router wherein each interface will contain complete
information about the possible destinations
The initial steps in configuring dialer profiles include
configuring static routes and dialer list similar to
legacy DDR
you need to configure the dialer and the physical
interfaces then
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Chapter 9 32
Verifying DDR Configuration
After configuring the interfaces, you need to verify
that they have been configured properly
To verify the DDR configuration, there are three
commands:
show dialer interface
show isdn active
show isdn status
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Troubleshooting ISDN DDR
The show and debug commands enable you to
verify and troubleshoot the DDR connections
show command - You can use the show dialer
command to view the DDR interfaces that made
the phone calls
debug command - You can use the debug dialer
command to view the DDR process to enable or
disable the connection
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Chapter 9 34
Case Study
The Blue Diamond Steel company opened a new
branch at Hyderabad. The organization uses regular
telephone line for data transmission. All the
departments of the Hyderabad branch send the
details of their daily transactions to the Gujaratbranch. The files that contain the transaction details
are very large in size.
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Chapter 9 36
Suggested Solution
Implement Cisco routers in the network and configure
ISDN on each router. The Cisco routers provide Dial
on Demand Routing (DDR) feature, which allows the
router to call the ISDN when it receives important
traffic. Setup the PRI service for data transmission,which provides 23 B channels and 1 D channel
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Chapter 9 38
Summary - II
Network Termination Device 2 (NT2) communicates
with the ISDN protocols
ISDN Router enables multiple computers on a LAN to
share a single ISDN BRI connection
Terminal Adapter (TA) converts some other form of
signaling to ISDN to enable non-ISDN devices, such
as the TE2 to work the 2-wire ISDN network
The U point is a 2-wire interface for connecting to the
(NT1)
The division of the wire into logical time slots is termed
as Time Division Multiplexing (TDM)
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Chapter 9 39
Summary - III
The S reference point provides a 4-wire interface
between the NT1 and the ISDN networking equipment
such as an ISDN adapter or a router
Basic Rate Interface (BRI) consists of two B channels
and one D channel
Primary Rate Interface (PRI) consists of multiple B and
D channels
The ISDN interfaces can be configured using the
interface command
The Internet Service Provider (ISP) provides the
switch type for the ISDN connection
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Chapter 9 40
Summary - IV
Service Profile IDentifier (SPID) is a set of numbers
for BRI connections that have a National ISDN-1 or
Nortel DMS-100 switch
The show interface command enables you to viewthe ISDN interface configuration
The show isdn status command enables you to view
the detailed status of the ISDN interfaces