Communications System Owner Manual

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Table Of Contents

Table of Contents
ABOUT THIS DOCUMENT
- PREREQUISITE SKILLS AND KNOWLEDGE
- DOCUMENT ORGANIZATION
- HOW TO MAKE COMMENTS ABOUT THIS DOCUMENT
1. INTRODUCTION TO CONNECTIVITY
- TRANSMISSION TYPES
- TRANSMISSION STATES
  - VOICE TRANSMISSION
    - Entering the Switch
    - Exiting the Switch
  - DATA TRANSMISSION
- MULTIPLEXED COMMUNICATION
- TRUNKING
2. COMMUNICATION SYSTEM NETWORKING (em AN OVERVIEW
- TYPES OF NETWORKS
- NETWORK EVOLUTION
- SOFTWARE CAPABILITIES
- NETWORK CALL PROCESSING
- NETWORK ADMINISTRATION
- PRIVATE NETWORK TRUNKS
- NETWORKING FEATURE PARAMETERS
3. TANDEM TIE TRUNK NETWORKS
- INTERACTIONS WITH OTHER NETWORKS
4. MAIN-SATELLITE/TRIBUTARY (MS/T) NETWORKS THROUGH THE UDP OR MULTIPREMISES PACKAGES
- MS/T CONFIGURATIONS
  - Main-Satellite Configuration
  - Main-Tributary Configuration
- MS/T FEATURES
- ENGINEERING CONSIDERATIONS
- INTERACTIONS
5. ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES
- ETN CONFIGURATIONS
- ETN TRUNKS
  - Access and Bypass Access Tie Trunks
  - Off-Net Trunks
- FEATURES
- ETN INTERACTIONS WITH OTHER NETWORKS
- ENGINEERING CONSIDERATIONS
6. DISTRIBUTED COMMUNICATIONS SYSTEM (DCS)
- DCS CLUSTERS
- DCS LINKS
  - Tie Trunks
  - Signaling Links
- DCS SIGNALING LINK CONNECTIONS
- TRANSPARENT FEATURES
- ENGINEERING CONSIDERATIONS
- ADMINISTRATION CONSIDERATIONS
7. DATA CONNECTIVITY - AN OVERVIEW
- DATA COMMUNICATIONS VARIABLES
- SPECIAL DATA FEATURES
8. DATA COMMUNICATIONS CAPABILITIES
- DTE CONNECTIONS
- LOCAL AREA NETWORK CONNECTIONS
- PUBLIC AND PRIVATE DATA NETWORK CONNECTIONS
  - PUBLIC DATA NETWORKS
    - Packet-Switched Public Data Networks
    - Circuit-Switched Public Data Networks
  - PRIVATE DATA NETWORKS
    - Terrestrial Private Data Network Links
    - Satellite Private Data Network Links
- TELEMARKETING HOST CONNECTIONS
  - THE ISDN GATEWAY
  - THE INTEGRATED TELEMARKETING GATEWAY
- DATA NETWORK ADMINISTRATION
9. DATA COMMUNICATIONS CONFIGURATIONS
- DSC AND PSC CONNECTIONS
- SNA NODE CONNECTIONS
- CONNECTIONS THROUGH PUBLIC OR PRIVATE DATA NETWORKS
A. RELATED DOCUMENTS
B. SYNCHRONIZATION OF DIGITAL FACILITIES
- THE NEED FOR SYNCHRONIZATION
- SYNCHRONIZATION HIERARCHY
- CHANGES TO THE SCS SOFTWARE MADE AVAILABLE VIA SOFTWARE PATCHES
- NETWORK SYNCHRONIZATION AND ENGIINEERING
- AVAILABILITY OF SYNCHRONIZATION SOURCES
- CONCLUSIONS ON SYNCHRONIZATION
- USE OF GENERIC 2 AS A SYSTEM CLOCK REFERENCE
- USE OF GENERIC 1 AS A SYSTEM CLOCK REFERENCE
C. TRUNKING TERMS AND CAPABILITIES
D. COMMUNICATIONS PROTOCOLS
- OSI MODEL
- STANDARD PROTOCOLS
- AT&T PROTOCOLS
E. LEAD DEFINITIONS
F. NETWORKING FEATURES - AVAILABILITY MATRIX
ABBREVIATIONS
GLOSSARY
INDEX

COMMUNICATIONS PROTOCOLS D-9

_ ______________________________________________________________________________________

Further

study( )

B Channel

Packet

switching

CCITT-ISO

OSI-related protocols

Leased

circuit

Circuit

switching

Telemetry

D Channel

Packet Signal

X.25

LAP-B

Layer 1 (I.430, I.431)

LAP-D (I.441)

X.25

Packet level

X.25

Packet level

Call control

I.451

End-to-end

user

signaling

Physical

Data link

Network

Transport

Session

Presentation

Application

Adapted from: Data and Computer Communications, by William Stallings, Macmillan Publishing Co., N.Y., 1988

Figure D-2. ISDN Protocols

Other Common Standards

In addition to standards formulated by the CCITT, many other standards are common. Most notable among

these non-CCITT standards are some of the most popular protocols at layers 1 and 2.

Layer 1 protocols include:

• RS-232C — A common physical interface used to connect DTE devices to voice-grade modems for use

in the public network.

• RS-449 — A replacement speciﬁcation for the RS-232C speciﬁcation. It was devised to overcome the

RS-232C distance restrictions and the lack of modem control that RS-232C procedures afford.

• RS-366A — A physical interface between a DTE and automatic calling equipment for data

communications.

Layer 2 protocols include:

• SDLC (Synchronous data link control) — An IBM protocol that has a 1 byte addressing ﬁeld and is

capable of transmitting messages in multiple frames.

• HDLC (High-level data link control) — A very common bit-oriented standard issued by the ISO. It

features a multi-byte addressing ﬁeld, but otherwise, is quite similar to SDLC, from which it was

derived.

• BSC (Binary synchronous communications) — An early IBM character-oriented, half-duplex protocol

that transmits messages consisting of strings of characters. Control information is provided by special

non-printing characters.