S Mandayam ECOMMSECE Dept Rowan University Electrical Communications

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Electrical Communications Systems ECE. 09. 433 Packet Switching Dr. Shreek Mandayam Electrical & Computer Engineering Rowan University

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Plan • Data Processing & Data Communications • • Communications Networks Packet Switched Networks OSI 7 -Layer Protocol Architecture TCP-IP Protocol Architecture

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University ECOMMS: Topics

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Sampling Quantization Source Encoder ADC Data Encryption Encoder Error Control Encoder Channel/ Line Encoder Modulator Analog i/p CODEC MODEM Audio Amp Reconstruction/ DAC Source Decoder Data Encryption Decoder Error Control Decoder DEMUX Analog o/p Equalization / Decision Circuits Demodulator Multiple access channel Antialiasing Filter MUX Digital Communications Transceiver

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Recall Message 2 Message 3 Circuit Switching 1 2 3 S 1 2 2 3 S Sync bits Packet Switching Message 1 Message 2 Message 3 Packetizing H 1 H 3 H 2 H 1 H 2 H 3 H 1 H 2 Demultiplexer Message 1 Multiplexer Digital Communication Paradigms Message 1 Message 2 Message 3 Header bits Depacketizing Message 1 Depacketizing Message 2 Depacketizing Message 3

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Communications Networking Router Step 1: Step 2: Step 3: ……. . Protocol Message Step 1: Step 2: Step 3: ……. . Protocol Medium Sender Receiver

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University A 3 -Layer Protocol Architecture File transfer application Communications service module Network access module Computer 1 Files and file transfer commands Comm related messages Comm network File transfer application Communications service module Network access module Computer 2

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University ISO OSI 7 -Layer Model 7 Application 6 Presentation 5 Session 4 Transport 3 Network 2 Data Link 1 Physical Please Do Not Touch Steve’s Pet Alligator

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University TCP-IP Protocol Architecture TCP-IP OSI Application User space Presentation Software Session Transport (host-to-host) Transport Internet Network Access Data Link Physical Firmware Hardware Operating system

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University TCP-IP Operation Example Host A App Y App X Host B Port or Service access point (SAP) App Y App X Logical connection (TCP) TCP IP Global network address Network access protocol #1 Physical Subnetwork attachment point address Router J IP Logical connection IP Network 1 NAP 2 Network access protocol #2 Physical Network 2

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University TCP-IP Protocol Packet User Data TCP header IP header Network header Application Byte Stream TCP Segment IP Datagram Network Level Packet

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University IP Header 4 Version 8 IHL 16 Type of Service Identification Time to Live 19 31 Total Length Flags Protocol Source Address Destination Address Options + Padding Fragment Offset Header Checksum 20 octets 0

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University TCP Header 0 4 10 16 Source Port 31 Destination Port Acknowledgement Number Data Offset Reserved U A P R R C S S G K H T S Y N F I N Checksum Window Urgent Pointer Options + Padding 20 octets Sequence Number

S. Mandayam/ ECOMMS/ECE Dept. /Rowan University Summary