Communication Network Protocols

Abinashi Dhungel

Outline

Part 1 : Protocol Suite OSI Protocol Suite TCP / IP Protocol Suite

Part 2: Recent Advances

Part 3 : Future Development

Communication Network Protocols

Rules and standards Regulate the exchange of messages Reliable and orderly flow of information among

processes

Communication Services Connection oriented

Reliable and in sequence Mechanism to acknowledge the receipt of a package Virtual Circuit (Network) / Circuit Switching (Hardware)

Connectionless Unreliable and best effort basis

May arrive at arbitrary order Datagram (Network) / Packet Switching (Hardware)

Communication Hardware and Software Design structured in layers Services – set of

operations a layer provide to layer above it through interface.

Peers - Corresponding entities in same layer

Protocol – set of rules defining how message or packets are exchanged between peers.

Layer k Layer kProtocol

Layer k + 1 Layer k + 1

Layer k - 1 Layer k - 1

Service provided by layer k

Network system architecture Series of layers and their protocols

Protocol suite OSI TCP / IP

OSI Protocols rarely used / General / Still Valid

TCP / IP Model not used / Protocols widely used

[Tanenbaum 2002]

OSI Protocol Suite

Physical Layer Transmission of Raw bit over communication

channel Mechanical, electrical, timing interface, physical

transmission medium.

Data Link Layer Ensures the reliable data transfer of frames

Group of bits (few hundred to few thousand bytes [Tanenbaum 2002])

Configuration, Error control, sequencing, flow control of frames

Medium Access Control (MAC) sublayer

Network Layer Sending Packets

(Basic unit of data transfers in network layer) Routing, Error and Flow control between nodes Virtual Circuit

Routing decision at connection In-order delivery

Datagram Routing decision packet-by-packet basis Requires reassembly of packets

Transport Layer End-to-end layer Interface between

communication subnetwork (Physical, data link and network layers)

Network independent layer (session, presentation, and application)

Breaks message into packets , sends to network layer

Session, Presentation, & Application Layers Session

Establish session between machines Dialog control (whose turn to transmit) Token management (preventing two parties from same

critical operation at the same time) Synchronization

Presentation Data Encryption, compression and code conversion

Computers with different data representation can communicate

Application Left to the designer of application

Egs. HTTP, File transfer, email

TCP / IP

Internet Layer Inject packets into any network

Packets travel independently to destination Might arrive in different order

IP (internet protocol) Deliver IP packets, routing, congestion control

(similar to OSI network layer)

Transport Layer Transport protocols

TCP Reliable, Connection oriented Bytestream into discrete messages, flow control

UDP Unreliable, connectionless protocol (prompt delivery than accurate delivery)

Application Layer TELNET

Virtual terminal FTP, SMPT, DNS

Recent Advances

Despite the maturity of Communication Networks Protocols like TCP / IP, many application specific protocols are used today [Clare, Agre, Yan 01].

Extensions on TCP in the satellite environment to effectively utilize the available capacity of the network path in satellite channels [Allman, Glover 99].

Traditional TCP/IP implementations have required far too much resources both in terms of code size and memory usage to be useful in small 8 or 16-bit systems [Dunkels 03].

Implemented two small generic and portable TCP/IP implementations, lwIP (lightweight IP) and uIP (micro IP), for 8 and 16 - bit microcontrollers [Dunkels 03].

Recent Advances

IP version 6 (IPv6) is a new version of the Internet Protocol, designed as the successor to IP version 4 (IPv4) .

Expanded Addressing Capabilities - increases the IP address size from 32 bits to 128 bits, to support more levels of addressing hierarchy, a much greater number of addressable nodes [Deering, Hinden 98].

IPv6 prevalance is still low but growing at smaller rate [Gunderson 08].

Deployment - Russia (0.76%), France (0.65%), Ukraine (0.64%), Norway (0.49%), and the United States (0.45%). Absolute deployment numbers, higher in China but relative number low 0.24% [Gunderson 08].

IPv6 has been implemented on all major operating systems in use in commercial, business, and home consumer environments. Mac OS X led in IPv6 penetration of 2.44%, followed by Linux (0.93%) and and and Windows Vista (0.32%) [Gunderson 08].

Future Development

More device support Ubiquitous Computing Ambient Computing

References

[Allman, Glover 99], “Enhancing TCP Over Satellite Channels using Standard Mechanisms”, Internet Society IETF Network Working Group RFC 2488, January 1999

[Clare, Agre, Yan 01] Clare, L.P., Agre, J.R., Tsun-Yee Yan, “ IEEE Proceedings on Aerospace Conference, 2001”, Volume 2, 10-17 March 2001 Page(s):2/943 – 2/950

[Dunkels 03] A. Dunkels, “Full TCP/IP for 8-bit architectures”, Proceedings of the First International Conference on Mobile Systems Applications and Services (MobiSys-03), San Francisco, CA, USA, 2003, pp. 85-98.

[Deering, Hinden 98] S. Deering, R. Hinden, “Internet Protocol, Version 6 (IPv6) Specification”, Internet Society IETF Network Working Group RFC 2460, December 1998

[Gunderson 08] Steinar H. Gunderson, "Global IPv6 statistics - Measuring the current state of IPv6 for ordinary users", Réseaux IP Européens, October 2008

[Tanenbaum 02] “Computer Networks”, 4th Edition, Andrew S. Tanenbaum, Prentice Hall, 2002

Questions ?