The user requirements for implementing ISDN at a site are low bandwidth and high stability.
An ISDN link should be installed at the access layer of the three layer hierarchial WAN model.
OSI Model
ISDN standards address the bottom three layers of the OSI model: network, data link, and physical.
These layers and the functions therin are:
1. The Network Layer: I TU-71.450-1 circuit switced and packet switched data
2. The Data Link Layer: LAPD- Flow control.
3. The Physical Layer: To transmit bits.
ISDN
Describe the 3 ISDN BRI data channels and each channel's function
1.B1- Data transfer
2.B2- Seperate data transfer
3.D- Instructs how bandwidth on B channels is allocated
ISDN protocols that start with "Q" are...Q.921-layer 2 functions, Q.931-Layer 3 functions
ISDN protocols that start with "I" are...I.100-terms of structure and other "I" series recomendations, I.200-server aspects, I.300-Network aspects
ISDN protocols that start with "E" are...E.164-internal addressing for ISDN
The five major devices in an ISDN implementation are:
1.TE1-device compatable with ISDN
2.TE2-device not compatable with ISDN
3.TA-adapter for non-compatable devices
4.NT1-connects four-wire ISDN connection with two-wire local loop
5.NT2-Directs traffic between NT1s and other devices
The four major reference points in an ISDN implementation are:
1.R=NT2-TA
2.S=connection into NT2
3.T=NT2-NT1
4.U=NT1-cloud
The function of PPP in an ISDN implementation is...to provide encapsulation.
It is important to know the ISDN switch type when configuring an ISDN connection because...it is checked by the service provider along with a SPID.
The SPID numbers are...a way to identify a line so that a profile of servies can be set up.
When configuring an ISDN connection it is important to know the SPID number because...It wouldn't connect tho the service provider without a SPID number.
