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ISDN Protocols
These protocols deal with ISDN issues:
·
E Specifies ISDN on the existing telephone network.
·
I Specifies Concepts, terminology, and Services.
·
Q Specifies switching and signaling.
*Keypoints:Your router will always be connected by the U interface into NT1.The BRI interface on your router is considered Terminal Equipment type 1 (TE1).Know the 3 benefits of ISDN over standard telephone service.The ISDN "Q" protocol specifies the type of switch that the router communicates with.Know that ISDN provide integrated voice and data capability.Know that ISDN standards define the hardware and call setup schemes for end-to-end digital con-nectivity.Know the Benefits for ISDN listed above.ISDN Function Groups
Devices connected to the ISDN network are known as terminals and have the following types:
·
TE1 Terminal Equipment type 1 understands ISDN standards. Like a BRI Interface on a
router.
·
TE2 Terminal Equipment type 2 predates ISDN standards. To use a TE2, you must have a
Terminal Adapter (TA).
ISDN Reference Points
ISDN uses four different reference points to define logical interfaces. They are as follows:
·
R Defines the reference point between non ISDN equipment and a TA
·
S Defines the reference point between user terminals and an NT2
·
T Defines the reference point between NT1 and NT2 devices
·
U Defines the reference point between NT1 devices and Line Termination Equipment.
(North America Only)
ISDN Benefits
1)
Full-time connectivity is spoofed on routers using DDR
2)
SOHO sites can be cheaply supported
3)
Can be used as a backup for leased lines
4)
Modem racking can be eliminated by using modem cards.
ISDN Channels
ISDN can either be Basic Rate ISDN (BRI) or Primary Rate ISDN (PRI).
BRI is 2 64 Kbps B Channels for data and one 16 Kbps D Channel for link management and connects
to NT1 for 4-wire connection.
PRI is 23 B Channels and 1 D Channel in the US or 30 B Channel and 1 D Channel in Europe.
Occasionally when configuring ISDN you will need to configure a Service Profile ID (SPID). A SPID
is a series of characters which can look like phone numbers. These numbers will identify your connec-
tion to the Switch at the CO. The SPIDs are processed during each call setup operation.
*Keypoints:Total bandwidth for a BRI connection is 144 Kbps (64+64+16) and connects to NT1 for 4-wire con-nection.A SPID is a series of characters that identifies you to a switch at the CO.A Terminal Adapter (TA) device is required to connect a V.35 interface to a BRI port.