2. Introduction
• Layered protocol architecture
• TCP/IP protocol suite
• OSI reference model
• Internetworking
Chapter 2 Protocols and the TCP/IP Suite 2
3. The Need for a Protocol Architecture
• Procedures to exchange data between devices
can be complex
• High degree of cooperation required between
communicating systems
Chapter 2 Protocols and the TCP/IP Suite 3
4. Example: File transfer
• Requires a data path to exist
• Tasks:
– Activate data communication path
– Source determines that destination is ready
– File transfer app destination file management app
is ready store file for user
– File format conversion
Chapter 2 Protocols and the TCP/IP Suite 4
5. Layered Protocol Architecture
• modules arranged in a vertical stack
• Each layer in stack:
– Performs related functions
– Relies on lower layer for more primitive functions
– Provides services to next higher layer
– Communicates with corresponding peer layer of
neighboring system using a protocol
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6. Key Features of a Protocol
• Set of rules or conventions to exchange blocks
of formatted data
• Syntax: data format
• Semantics: control information (coordination,
error handling)
• Timing: speed matching, sequencing
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7. TCP/IP Layers
• Physical
• Network access
• Internet
• Transport Application
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8. TCP and UDP
• TCP:
– connection-oriented
– Reliable packet delivery in sequence
• UDP:
– connectionless (datagram)
– Unreliable packet delivery
– Packets may arrive out of sequence or duplicated
Chapter 2 Protocols and the TCP/IP Suite 8
11. Operation of TCP and IP
• IP implemented in end systems and routers,
relaying data between hosts
• TCP implemented only in end systems,
assuring reliable delivery of blocks of data
• Each host on subnetwork has unique IP
address
• Each process on each process has unique IP
port number
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14. TCP Applications
• SMTP: Simple Mail Transfer Protocol
• FTP: File Transfer Protocol
• telnet: remote login
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15. OSI Reference Model
• Application
• Presentation
• Session
• Transport
• Network
• Data link
• physical
Chapter 2 Protocols and the TCP/IP Suite 15
17. Internetworking Terms
• Communication network
• Internet
• Intranet
• Subnetwork
• End system
• Intermediate system
• Bridge
• Router
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18. Routers
• Provide link between networks
• Accommodate network differences:
– Addressing schemes
– Maximum packet sizes
– Hardware and software interfaces
– Network reliability
Chapter 2 Protocols and the TCP/IP Suite 18