be used for either function. Interactive Media
Activity Drag and Drop: ISDN Reference Points When the
student has completed this activity, the student will be able
to correctly identify the ISDN reference points. Web
Links Integrated Servicews Digital Network (ISDN)
http://www.cisco.com/univercd/cc/
td/doc/cisintwk/ito_doc/isdn.htm
Content
4.1 ISDN Concepts 4.1.6 Determining the
router ISDN interface In the United States, the customer is
required to provide the NT1. In Europe and various other
countries, the telephone company provides the NT1 function and
presents an S/T interface to the customer. In these
configurations, the customer is not required to supply a
separate NT1 device or integrated NT1 function in the terminal
device. Equipment such as router ISDN modules and interfaces
must be ordered accordingly. To select a Cisco router with the
appropriate ISDN interface, do the following:
- Determine whether the router supports ISDN BRI. Look on the
back of the router for a BRI connector or a BRI WAN Interface
Card (WIC).
- Determine the provider of the NT1. An NT1
terminates the local loop to the central office (CO) of the
ISDN service provider. In the United States, the NT1 is
Customer Premise Equipment (CPE), meaning that it is the
responsibility of the customer. In Europe, the service provider
typically supplies the NT1.
- If the NT1 is CPE, make
sure the router has a U interface. If the router has an S/T
interface, then it will need an external NT1 to connect to the
ISDN provider.
If the router has a connector
labeled BRI then it is already ISDN-enabled. With a native ISDN
interface already built in, the router is a TE1. If the router
has a U interface, it also has a built-in NT1. If the router
does not have a connector labeled BRI, and it is a
fixed-configuration, or non-modular router, then it must use an
existing serial interface. With non-native ISDN interfaces such
as serial interfaces, an external TA device must be attached to
the serial interface to provide BRI connectivity. If the router
is modular it may be possible to upgrade to a native ISDN
interface, providing it has an available slot. Caution:
A router with a U interface should never be connected to an
NT1 as it will damage the interface. Web Links
Integrated Services Digital Network (ISDN)
http://www.cisco.com/univercd/cc/ td/doc/ cisintwk/ito_doc/
isdn.htm
Content 4.1 ISDN Concepts
4.1.7 ISDN switch types Routers must be configured to
identify the type of switch with which they will communicate.
Available ISDN switch types vary, depending in part on the
country in which the switch is being used. As a consequence of
various implementations of Q.931, the D channel signaling
protocol used on ISDN switches varies from vendor to vendor.
Services offered by ISDN carriers vary considerably from
country to country or region to region. Like modems, each
switch type operates slightly differently, and has a specific
set of call setup requirements. Before the router can be
connected to an ISDN service, it must be configured for the
switch type used at the CO. This information must be specified
during router configuration so the router can communicate with
the switch, place ISDN network level calls, and send data. In
addition to knowing the switch type the service provider is
using, it may also be necessary to know what service profile
identifiers (SPIDs) are assigned by the telco. A SPID is a
number provided by the ISDN carrier to identify the line
configuration of the BRI service. SPIDs allow multiple ISDN
devices, such as voice and data equipment, to share the local
loop. SPIDs are required by DMS-100 and National ISDN-1
switches. SPIDs are used only in North America and Japan. The
ISDN carrier provides a SPID to identify the line configuration
of the ISDN service. In many cases when configuring a router,
the SPIDs will need to be entered. Each SPID points to line
setup and configuration information. SPIDs are a series of
characters that usually resemble telephone numbers. SPIDs
identify each B channel to the switch at the central office.
Once identified, the switch links the available services to the
connection. Remember, ISDN is typically used for dialup
connectivity. The SPIDs are processed when the router initially
connects to the ISDN switch. If SPIDs are necessary, but are
not configured correctly, the initialization will fail, and the
ISDN services cannot be used. Web Links ISDN Switch
Types, Codes, and Values http://www.cisco.com/en/US/products/sw/
iosswrel/ps1831/ products_command_reference_
chapter09186a00800eea24.html
Content 4.2 ISDN
Configuration 4.2.1 Configuring ISDN BRI The command
isdn switch-type switch-type can be configured
at the global or interface command mode to specify the provider
ISDN switch. Configuring the isdn switch-type command in
the global configuration mode sets the ISDN switch type
identically for all ISDN interfaces. Individual interfaces may
be configured, after the global configuration command, to
reflect an alternate switch type. When the ISDN service is
installed, the service provider will issue information about
the switch type and SPIDs. SPIDs are used to define the
services available to individual ISDN subscribers. Depending on
the switch type, these SPIDs may have to be added to the
configuration. National ISDN-1 and DMS-100 ISDN switches
require SPIDs to be configured, but the AT&T 5ESS switch
does not. SPIDs must be specified when using the Adtran ISDN
simulator. The format of the SPIDs can vary depending on the
ISDN switch type and specific provider requirements. Use the
isdn spid1 and isdn spid2 interface configuration
mode commands to specify the SPID required by the ISDN network
when the router initiates a call to the local ISDN exchange.
Configuration of ISDN BRI is a mix of global and interface
commands. To configure the ISDN switch type, use the isdn
switch-type command in global configuration mode:
Router(config)#isdn switch-type switch-type The
argument switch-type indicates the service provider
switch type. To disable the switch on the ISDN interface,
specify isdn switch-type none. The following example
configures the National ISDN-1 switch type in the global
configuration mode: Router(config)#isdn switch-type basic-ni
To define SPIDs use the isdn spid# command in
interface configuration mode. This command is used to define
the SPID numbers that have been assigned for the B channels:
Router(config-if)#isdn spid1 spid-number
[ldn]
Router(config-if)#isdn spid2
spid-number [ldn] The optional ldn
argument defines a local dial directory number. On most
switches, the number must match the called party information
coming in from the ISDN switch. SPIDs are specified in
interface configuration mode. To enter interface configuration
mode, use the interface bri command in the global
configuration mode: Router(config)#interface bri
slot/port
Router(config)#interface
bri0/0
Router(config-if)#isdn spid1 51055540000001
5554000
Router(config-if)#isdn spid2 51055540010001
5554001 Lab Activity Lab Exercise: Configuring ISDN
BRI (U-Interface) In this lab, the student will configure an
ISDN router to make a successful connection to a local ISDN
switch. Web Links Configuring ISDN BRI