Transcript 物理層 （Physical layer）

Physical Layer
Ryo Nakamura
Abstract
・ OSI reference model
・ Encoding
・ Protocol
- Protocol for Ethernet
・ Cable
- Metal cable
・ Coaxial cable
・ Twisted pair cable
- Optical fiber
- Wireless Communication
・Radio
・Free Space Optics (FSO)
・ Device
OSI reference model
OSI reference model
・ In 1977, work on a layered model of network architecture,
which was to become the OSI model, started in the
American National Standards Institute (ANSI) working
group on Distributed Systems (DISY). With the DISY
work and worldwide input, the International Organization
for Standardization(ISO) began to develop its OSI
networking suite.
・ OSI has two major components: an abstract model of
networking (the Basic Reference Model, or seven-layer
model) and a set of concrete protocols.
[Wikipedia]
OSI reference model
Layer 7
Application
Layer 6 Presentation
Layer 5
Session
Layer 4
Transport
Layer 3
Network
Network process to application
Data representation and encryption
offer service
Signaling
End-to-end connections and reliability
Path determination and logical addressing
offer communication
Layer 2
Data Link
Layer 1
Physical
Physical addressing
Media, signal and binary transmission
OSI Upper Layer
・ Application Layer
・ Session Layer
When to start
Application
Signaling
・ Presentation Layer
DATA
DATA
Format
OSI Lower Layer
・ Transport Layer
・ Data Link Layer
0101
Reliability
Data transmission
at the node interval
・ Network Layer
Routing
・ Physical Layer
0101
Physical connection
Function of Physical Layer
⇒ Conversion data into electrical signal
Electrical Signal
DATA
Buffer
Ethernet
controller
LAN adapter
Ethernet controller : Encode data
PHY (Physical) tip : D/A (Digital / Analog) conversion
PHY tip
⇒ Conversion electrical signal into data
Electrical Signal
Trance
PHY tip
MAC tip
Buffer
LAN adapter
Trance : Insulate the inside and the outside of LAN adapter
PHY tip : Judge a bit from electrical signal
MAC tip : Take out MAC frame based on Ethernet specifications from bit string
Encoding
Encoding
・ NRZ
(Non-Return to Zero)
0 → Low Level
1 → Hi Level
・ Manchester
0 → Hi ⇒Low
1 → Low⇒Hi
※ 10BASE5、2、-T
※ 1000BASE-X
・ NRZI
(Non-Return to Zero Inversion)
0 → No Change Level
1 → Change Level
※ FDDI, 100BASE-FX
・MLT-3
0 → No Change Level
1 → Change Level
(Middle⇒Hi⇒Middle⇒Low⇒)
※ 100BASE-TX、CDDI
Encoding
Block Encoding
・ 4B / 5B
(4-bit / 5-bit)
Decimal ／ 4-bit ／ 5bit
0 ／ 0000 ／ 11110
2 ／ 0010 ／ 10100
4 ／ 0100 ／ 01010
6 ／ 0110 ／ 01110
8 ／ 1000 ／ 10010
A ／ 1010 ／ 10110
C ／ 1100 ／ 11010
E ／ 1110 ／ 11100
1 ／ 0001 ／ 01001
3 ／ 0011 ／ 10101
5 ／ 0101 ／ 01011
7 ／ 0111 ／ 01111
9 ／ 1001 ／ 10011
B ／ 1011 ／ 10111
D ／ 1101 ／ 11011
F ／ 1111 ／ 11101
Protocol
Protocol
・ RS-232C (Recommended Standard 232C)
・ ISDN (Integrated Services Digital Network)
・ xDSL (x Digital Subscriber Line)
- ADSL (Asymmetric DSL)
・ IEEE 802.11 (Wireless LAN)
・ SDH (Synchronous Digital Hierarchy)
SONET (Synchronous Optical NETworking)
・ Protocol for Ethernet
RS-232C
⇒ Connect a peripheral devices to a PC
（Serial communication method）
9 Pin Serial Port
25 Pin Serial Port
Pin No
signal name
IN/OUT
contents
1
DCD
IN
Data Carrier Detect
2
RxD
IN
Receive Data
3
TxD
OUT
Transmit Data
4
DTR
OUT
Data Terminal Ready
5
GND
-
Ground
6
DSR
IN
Data Set Ready
7
RTS
OUT
8
CTS
IN
Clear To Send
9
RI
IN
Ring Indicator
Request transmission
ISDN
⇒ The digital communications network that unified telephone,
FAX and data communication
INSNet64
2 channels for communication
64kbps(B channel)
1 channel for control
16kbps(D channel)
B channel
INSNet64
INSNet1500
D channel
speed
64kbps*2
16kbps*1
128kbps
64kbps*23
64kbps*1
1.5Mbps
PC
ISDN
TA
Phone
DSU
IP Phone
DTE
DCE
TA (Terminal Adapter) : Convert Non-ISDN signal into ISDN signal
DSU (Digital Service Unit) : Synchronization control & Signal conversion
※DTE (Data Terminal Equipment) : Data handling device
DCE (Data Circuit-terminating Equipment) : Converting or Coding device
xDSL
⇒ The general term of high-speed digital data
communication technology with telephone wire
Down speed
Up speed
SDSL (Symmetric DSL)
160kbps～2.0Mbps
160kbps～2.0Mbps
ADSL (Asymmetric DSL)
1.5Mbps～50Mbps
500kbps～12Mbps
HDSL (High bit rate DSL)
1.5Mbps～2.0Mbps
1.5Mbps～2.0Mbps
13Mbps～52Mbps
1.5Mbps～2.0Mbps
VDSL (Very high bit rate DSL)
Digital
ADSL
Analog
Phone
Splitter
PC
modular jack
Modem
Modem (MOdulator-DEMotulatot) : Convert Ethernet signal into ADSL signal
Splitter : Divide Voice signal and Data signal
IEEE 802.11
⇒one of the wireless LAN related standards
Decision time
Frequency band
Official speed
IEEE 802.11
1997
2.4～2.5GHz
2Mbps
IEEE 802.11b
October, 1999
2.4～2.5GHz
11Mbps / 22Mbps
IEEE 802.11a
October, 1999
5.15～5.35GHz
5.47～5.725GHz
(Max)54Mbps
IEEE 802.11g
June, 2003
2.4～2.5GHz
54Mbps
IEEE 802.11j
--
4.9～5.0GHz
5.03～5.091GHz
54Mbps
IEEE 802.11n
--
2.4GHz / 5GHz
100Mbps～
SONET/SDH
⇒ The international standard
of the high speed digital
communication method
with optical fiber
Important
SONET
SDH
OC-1
‐
OC-3
STM-1
155.52Mbps
OC-9
‐
466.56Mbps
OC-12
STM-4
622.08Mbps
OC-18
‐
933.12Mbps
OC-24
‐
1244.16Mbps
OC-36
‐
1,866.24Mbps
OC-48
STM-16
2,488.32Mbps
OC-192
STM-64
9,953.28Mbps
OC : Optical Carrier
Transmission speed
51.84Mbps
Protocol for Ethernet
Transmission speed
Maximum length
Cable
Encoding
10BASE-5
10Mbps
500m
Coaxial cable
Manchester
10BASE-2
10Mbps
185m
Coaxial cable
Manchester
10BASE-T
10Mbps
100m
Twisted pair
cable
Manchester
100BASE-TX
100Mbps
100m
Twisted pair
cable
4B/5B + MLT-3
1000BASE-T
1Gbps
100m
Twisted pair
cable
4DPAM5(8BIQ4)
Optical fiber
4B/5B + NRZI
Optical fiber
8B/10B + NRZ
Optical fiber
8B/10B + NRZ
Optical fiber
8B/10B + NRZ
Multi mode:412m(half duplex)
100BASE-FX
100Mbps
2km(full duplex)
Single mode:20km(full duplex)
1000BASE-SX
1Gbps
1000BASE-LX
1Gbps
Multi mode:550m
Multi mode:550m
Single mode:5km
1000BASE-ZX
1Gbps
100km
Cable
Coaxial cable
1. Inner conductor
2. Insulator surrounding the Inner conductor
3. Metallic shield and outer conductor
4. Outer insulating jacket
Characteristic
・ Few leaks of the electromagnetic wave to the outside.
・ Able to bend.
・ Able to transmit of a wide frequency range.
・ Structure is complicated, and price is high.
10BASE5 (Thick cable, yellow cable)
Transceiver
2.5m~
Thick Coax
10mm
Transceiver Cable
~50m
N Connector
N Terminator
AUI connector
NIC
Terminator : prevent the reflection of the signal
NIC : Network Interface Card
10BASE2 (Thin cable)
Thin Coax
NIC
5mm
BNC T Connector
Twisted pair cable
UTP (Unshielded twisted pair)
TX＋
TX－
STP (Shielded twisted pair)
Characteristic
RX＋
RX－
TX : Transmit pair
RX : Receive pair
・ Cheap and Easy to treat.
・ Wire freely.
・ Affected by the powerful electricity
and electromagnetic wave.
Category
Maximum Frequency
Transmission speed
example
Cat1
―
20kbps
telephone wire
Cat2
1MHz
4Mbps
ISDN
Cat3
16MHz
10Mbps
10BASE-T
Cat4
20MHz
16Mbps
Token Ring, ATM
Cat5
100MHz
100Mbps
100BASE-TX, ATM(OC-3),
CDDI
Cat5-e
100MHz
1Gbps
1000BASE-T
Cat6
250MHz
1.2Gbps
1000BASE-TX
Cat6-e
500MHz
10Gbps
10GBASE-T
Cat6-a
(STP only)
500MHz
10Gbps
10GBASE-T
Cat7(STP only)
600MHz
10Gbps
10GBASE-T
e : enhanced
a : augmented
Optical fiber
Core : Light advances.
Cladding : Light is reflected.
Buffer : Relax shock.
Jacket : Protect.
Multi mode
Single mode
・ Strong to bend.
・ Little transmission loss.
・ Easy to connect.
・ Made of quartz glass.
( Core:Ge,P , Cladding:B,F)
・ Cheap.
・ Made of plastic.
(Cladding:fluorine-based polymer)
Conversion between Electricity and Light
Laser diode
Photo diode
e.g.
CATV
Wireless Communication
・ The wiring space is unnecessary.
・ Mobile communication is possible.
・ Able to build LAN immediately.
・ Able to communicate outdoors.
【Radio】
【FSO】
・ Electric wave
・ Infrared ray (IR)
or Visible spectrum
・ weak for obstacle
・ license is unnecessary
・ PC, remote controller
・ IrDA ⇒ UFIR
・ strong for obstacle
(・ license is necessary)
・ mobile phone, PHS
・ Bluetooth (IEEE 802.15.1)
EM spectrum
Bluetooth
・ Use frequency band of 2.4GHz.
・ Transmission length is radius of 10~100m.
・ Low power consumption
・ Low cost
Version
1.x (1.1,1.2)
2.x(2.0, 2.1)+EDR
Symmetry type
Asymmetry type
Transmission speed
down
up
432.6kbps
723.2kbps
57.6kbps
1.3069Mbps
2.1781Mbps
177.1kbps
IrDA (Infrared Data Association)
・ Use Infrared ray (IR).
・ Used for mobile game.
Transmission speed
30cm
1m
SIR
115kbps
IrDA ver1.2
IrDA ver1.0
MIR
1Mbps
IrDA ver1.3
IrDA ver1.1
FIR
4Mbps
IrDA ver1.3
IrDA ver1.1
VFIR
16Mbps
UFIR
100Mbps
IrDA ver1.4
Other communication style
・ Communications Satellite
⇒The wireless communication
that use the microwave from
artificial satellite
・ Power Line Communication (PLC)
⇒Technology to use a power line
as telecommunication line.
Device
Repeater HUB
⇒ Reproduce and Relay signal.
collision
A
B
C
D
Function of Repeater HUB
・ Retiming function
⇒ The transmission signal comes under various influence of
decrement, the distortion of the wave pattern, increase of the jitter in
a cable during transmission. Repeater HUB has a function to restore
the signal that It received to keep quality as the electrical signal in a
transmission process and call it “Retiming function".
・ Preamble reproducing function
⇒ Continuation of 1 and 0 of 7 bytes to be called Preamble is added
to the top of the communication frame that drifts to a cable, but there
is the case that phenomena such as the bit loss occur for this
preamble in a transmission process. We call a function to return this
preamble to an original state “Preamble reproduction function".
Switching HUB
⇒ Repeater Hub + Bridge
A
B
C
D