applied data networking © 2003, hans kruse and shawn ostermann itl basics of encoding and wiring
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Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
ITLBasics of Encoding and Wiring
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Objectives
Quick overview of wide-area communications
Define the term “Structured Wiring” Define "analog" and "digital" data. List the common methods used to
encode analog/digital data using analog/digital signaling.
Discuss transmission media and wiring system standards
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Wide-Area Data Communication Nomenclature
DTE DCE
Wide Area Network
Short-Distance Connection
Data Consumer or Local Area Network
Router
Workstation
Server/Mainframe
RS-232
V.35 RS449/530
HSSI
Modem
CSU/DSU
DS-0
ISDN
DS-1 DS3
OC1 OC3 OC12
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
RS232-C Connections
DTE DCE
Protective Ground
TD (Transmit Data)
RD (Receive Data)
RTS (Request to Send)
CTS (Clear to Send)
DSR (Data Set Ready)
Signal Ground
CD (Carrier Detect)
RD (Ring Detect)
DTR (Data Terminal Ready)
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Transmission Media
Guided Media– Twisted Pair– Coaxial Cable– Optical Fiber
Unguided Media– “Broadcast”-type radio
transmission» Wireless LANs, Cell Phones, PCS
– Satellite– Point-to-Point Microwave
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Transmission Systems
Basic multiplexing– DS-n (T1, DS3)– SONET (OC-3, OC-12, etc)– WDM
Multiplexing and Other Functions– Ethernet– Frame Relay– ATM
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Structured Wiring
Main Cross-Connect (Main Distribution Frame)– Riser Cable(“Backbone”)
Intermediate Cross-Connect (Int. Dist. Frame)– Horizontal Wiring
Jack Field– Drop Cable
Workstation
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Why use Hierarchical Wiring?
Flexibility = Lower CostFrom Bates, Voice and Data Communications Handbook:
– Estimated Cost for 50 single wire pulls:$15,568
– Estimated Cost for 50 dual wire pulls:$16,935
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Wiring Standards
Building Wiring Standards– Electronic Industries Association– Telecommunications Industry
Association– EIA/TIA 568 Commercial Building
Wiring Standard “Outside Plant”
– Bell Labs technical publications– Now maintained by Telcordia
(formerly Bellcore)
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
RJ-What?
As an aside for the eternally curious:
The RJxx nomenclature appears in the legal documents used by the FCC to identify permitted methods to connect telecom equipment to the network
For the really, really curious:
Title 47 CFR, Part 68, Subpart F, Section 502
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Signal Transmission Overview
Analog Data
over
Analog Transmission Systems
Digital Data
over
Analog Transmission Systems
Analog Data
over
Digital Transmission Systems
Digital Data
over
Digital Transmission Systems
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Analog Signaling of Digital Data
Encode "0" and "1" as changes in one signal property
Amplitude Shift Keying: Use two signal amplitudes, one for each bit value.
Frequency Shift Keying: Change the signal frequency to indicate the bit value.
Phase Shift Keying: Create a phase change relative to the most recent bit to indicate the bit value
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Signaling of Analog Information
Voice Codec– Pulse Code Modulation (PCM)– Compressed Voice
Video Codec
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Encoding ExamplePCM
Example: Voice 4000 Hz Sample at twice the highest frequency
(8000 samples per second) 8 bits per sample Result: 64kbps
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital SignalingDigital Data
Encoding Schemes: NRZ Manchester Differential Manchester Bipolar - AMI
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Signaling of Digital Data
Manchester Code
1 10 1 0
Every bit position has a transition (clocking)Signal has no DC componentTransition Direction Encodes the DataUsed in Ethernet
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Bipolar AMI Coding
1 1 1 10 0
Used in T1 Signaling
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Levels (Wiring) and Categories (System Performance)
Level/CAT 1 1Mbps
Level/ CAT 2 4Mbps
Level/ CAT 3 16Mbps
Level/ CAT 4 20Mbps
Level/ CAT 5 100Mbps1000 Mbps (4 pair)
100m max distance
Level/ CAT 5E 100Mbps1000 Mbps (4 pair)
Level/ CAT 6 200-250MHz Not yet a standard
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Cable standards versus system performance
Source: http://telecom.copper.org/networking.html
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Applications
Source: Lucent Technologies
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Ethernet
Designed as a broadcast medium; each transmission is received by every station
Based on a bus architecture Manchester Encoding Several Media Types
– 10Base5– 10Base2– 10Base-T– 10Base-F
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
10Base-T
Simulates the Ethernet bus using an active star topology.
Uses unshielded twisted pair wiring. “4-pair” (8 conductor) wiring is
normally used, but only 2 pairs are used – 1 transmit pair one receive pair
Each station connects to a central hub.– Cables are wired “straight through”– Hub ports are “crossed”
(transmit/receive are reversed
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Fast Ethernet
All use a star topology 100Base-TX
– Two pair copper wire (Cat 5)– Same pin-out at 10Base-T, better wire
100Base-FX– Two fibers
100Base-T4– Rarely used; 4 pair lower quality (cat 3)
wires 1000Base-X (4 pair Cat 5 or 5E)
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
FDDI
100 Mbps Ring Usually based on optical fiber Based on the Token Ring Standard Provides capacity pre-allocation Economics:
– Ethernet is cheaper than token ring and does almost as good a job – so it wins
– Fast Ethernet is cheaper than FDDI and does almost as good a job – so it wins
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Other Stuff
The slides after this one have probably not been used in class unless a specific question came up
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Phase and Amplitude Shift KeyingExample: Eight Levels
000
011
001
100
010
101
110
111
90 degreesnormal amplitude
180 degreesdouble amplitude
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Signaling of Digital Data
NRZ-L coding (Non-Return to Zero, Level)
1 10 1 0
Multiple bits may be sent without a transitionSignal has a DC componentExample: RS-232 uses +3V for "0" and -3V for
"1"
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Signaling of Digital Data
NRZI coding (Invert on One)
1 10 1 0
Multiple bits may be sent without a transitionSignal has a DC componentPolarity insensitive, partially self-timingExample: ISDN
Applied Data Networking© 2003, Hans Kruse and Shawn Ostermann
Digital Signaling of Digital Data
Differential Manchester Code
1 10 1 0
Every bit position has a transition (clocking)
Signal has no DC component and is polarity - neutral
Differential Signal provides some error detection