Application
Transport
Network
Link
Physical
NUS.SOC.CS2105
Ooi Wei Tsang
you are
here
Network
host-to-host
Link
node-to-node
frame-by-frame
101101001000100101010
NUS.SOC.CS2105
Ooi Wei Tsang
Physical
node-to-node
bit-by-bit
NUS.SOC.CS2105
Ooi Wei Tsang
Possible Link Layer Services
Framing
NUS.SoC.CS2105
Ooi Wei Tsang
Shared
Point-toPoint
Possible Link Layer Services
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SOC.CS2105
Ooi Wei Tsang
Possible Link Layer Services
Flow Control
NUS.SoC.CS2105
Ooi Wei Tsang
Possible Link Layer Services
Reliable
Unreliable
NUS.SoC.CS2105
Ooi Wei Tsang
Error
Detection &
Recovery
Possible Link Layer Services
NUS.SoC.CS2105
Ooi Wei Tsang
Link Layer Adapter
NUS.SoC.CS2105
Ooi Wei Tsang
Ethernet
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SoC.CS2105
Ooi Wei Tsang
source and destination address
NUS.SoC.CS2105
Ooi Wei Tsang
MAC Address
90:AF:F4:CA:BA:03
NUS.SoC.CS2105
Ooi Wei Tsang
type
NUS.SoC.CS2105
Ooi Wei Tsang
CRC
NUS.SoC.CS2105
Ooi Wei Tsang
CRC
Cyclic Redundancy Check
NUS.SoC.CS2105
Ooi Wei Tsang
d data bits
NUS.SOC.CS2105
Ooi Wei Tsang
r CRC bits
d data bits
=nx
NUS.SOC.CS2105
Ooi Wei Tsang
r CRC bits
r+1 bits G
d data bits
= nx
NUS.SOC.CS2105
Ooi Wei Tsang
r CRC bits
r+1 bits G
NUS.SOC.CS2105
Ooi Wei Tsang
r
D2
xor R = nG
d data bits
= nx
NUS.SOC.CS2105
Ooi Wei Tsang
r CRC bits
r+1 bits G
CRC
NUS.SoC.CS2105
Ooi Wei Tsang
data
NUS.SoC.CS2105
Ooi Wei Tsang
preamble
NUS.SoC.CS2105
Ooi Wei Tsang
Shared
Point-toPoint
Different Link Layer Services
NUS.SoC.CS2105
Ooi Wei Tsang
Multiple
Access
Protocols
NUS.SoC.CS2105
Ooi Wei Tsang
1. Channel
Partitioning
TDM, FDM
NUS.SoC.CS2105
Ooi Wei Tsang
2. Taking Turns
NUS.SoC.CS2105
Ooi Wei Tsang
Polling
NUS.SoC.CS2105
Ooi Wei Tsang
Token Passing
NUS.SoC.CS2105
Ooi Wei Tsang
3. Random
Access
NUS.SoC.CS2105
Ooi Wei Tsang
Slotted ALOHA
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SOC.CS2105
Ooi Wei Tsang
ALOHA
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SOC.CS2105
Ooi Wei Tsang
CSMA
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SOC.CS2105
Ooi Wei Tsang
CSMA/CD
NUS.SoC.CS2105
Ooi Wei Tsang
NUS.SOC.CS2105
Ooi Wei Tsang