Introduction and Background Danny Dolev Danny Dolev * The lecture - PDF document

✂ ✁ ✂ � � ✂ ✁ ✂ ✂ ✂ � ✂ ✂ ✁ ✂ ✂ ✁ ✁ � 3/ Communication Networks and Protocols* Introduction and Background Danny Dolev Danny Dolev * The lecture notes are based in part on the lecture notes of Dr. Yuval The lecture notes are based in part on the lecture notes of Dr. Yuval Yarom Yarom, Prof. , Prof. Raj Jain Raj Jain,, Prof. Don ,, Prof. Don Towsley Towsley and and * Prof. S. Keshav Prof. S. Keshav Comm 2001-2002 1 The team Bibiliography Bibiliography → Kurose & Ross, Kurose & Ross, ✁ Computer Networking Computer Networking → → A.S. A.S.Tanenbaum Tanenbaum, , ✁ Computer Networks (3rd Edition) Computer Networks (3rd Edition) → ✁ An Engineering Approach to Computer Networking → S. S. Keshav Keshav, , An Engineering Approach to Computer Networking → → Comer??? Comer??? → ✁ TCP/IP Illustrated, Volume 1 → W.R.Stevens, W.R.Stevens, TCP/IP Illustrated, Volume 1 → → Gallager Gallager & & Bertsekas Bertsekas, , ✁ Data Networks Data Networks → The lecture notes are based in part on lecture notes of Prof. Don Towsley The lecture notes are based in part on lecture notes of Prof. Don Towsley, , Prof. James Kurose, Dr. Yuval Yarom Yarom, Prof. , Prof. Raj Jain Raj Jain, Prof. Keith Ross , Prof. Keith Ross Prof. James Kurose, Dr. Yuval and Prof. S. Keshav Keshav and Prof. S. Comm 2001-2002 Danny Dolev 2

� � � � � � � � � � � � � � � � � � � � � � � � � ✁ � � ✂ � � ✁ ✁ � � � � � � ✂ ✂ ✁ ✂ ✂ � � ✂ � � � � � � � 3/ Part I: Introduction Goals: Goals: Overview: Overview: get context, overview, � get context, overview, � feel feel � � of of economic drive economic drive networking networking objective objective more depth, detail later more depth, detail later in course in course what � what � s the Internet s the Internet approach: approach: what � s a protocol? what � s a protocol? descriptive descriptive network edge network edge use Internet as example use Internet as example network core network core access net, physical media access net, physical media performance: loss, delay performance: loss, delay protocol layers, service models protocol layers, service models backbones, NAPs backbones, NAPs, ISPs , ISPs history history ATM network ATM network Comm 2001-2002 Danny Dolev 3 Economic Drive Today � s economy Today � s economy manufacturing, distributing, and retailing elements manufacturing, distributing, and retailing elements but also but also publishing publishing banking banking film making… film making …. . main � main � product product � � is creation and dissemination of information is creation and dissemination of information part of the part of the � � information economy information economy � � Future economy will to be dominated by information exchange Future economy will to be dominated by information exchange e.g. smart home and wireless tags on groceries e.g. smart home and wireless tags on groceries Comm 2001-2002 Danny Dolev 4

✁ � ✁ � � � � � � ✁ ✁ � ✁ � ✁ ✁ � � ✁ ✁ � ✁ ✁ ✁ 3/ The Objective Ways to represent all types of information as bits Ways to represent all types of information as bits Ways to move lots lots of bits of bits everywhere, cheaply everywhere, cheaply , and with , and with quality of quality of Ways to move service service need to engineer computer networks to meet these objectives need to engineer computer networks to meet these objectives Your generation is going to merge the current networks (telephony Your generation is going to merge the current networks (telephony and Internet) with sound-fiction services. and Internet) with sound-fiction services. Comm 2001-2002 Danny Dolev 5 Common network technologies Two successful computer networks Two successful computer networks telephone network telephone network Internet Internet What comes next? What comes next? next-generation � Internet � next-generation � Internet � G3 cellular technology G3 cellular technology something like universal wireless communication network something like universal wireless communication network We will study these technologies We will study these technologies Comm 2001-2002 Danny Dolev 6

� ✁ � � � � � ✁ � � � � � � � � � � � � � � � � � � � � � � 3/ What � s the Internet: � nuts and bolts � view ������ millions of connected computing millions of connected computing ����������� devices: hosts, end-systems devices: hosts, end-systems ������ pc ✁ s workstations, servers s workstations, servers ������ pc PDA PDA ✁ s phones, toasters s phones, toasters ��������� running network apps running network apps communication links communication links fiber, copper, radio, satellite fiber, copper, radio, satellite ������������ routers: forward packets (chunks) of routers: forward packets (chunks) of data thru network data thru network ������� ������� Comm 2001-2002 Danny Dolev 7 What � s the Internet: � nuts and bolts � view protocols : protocols : control sending, receiving of control sending, receiving of ������ ����������� msgs msgs ������ e.g., TCP, IP, HTTP, FTP, PPP e.g., TCP, IP, HTTP, FTP, PPP ������ Internet: Internet: � � network of networks network of networks � � ��������� loosely hierarchical loosely hierarchical public Internet versus private intranet public Internet versus private intranet Internet standards Internet standards RFC: Request for comments RFC: Request for comments ������������ IETF: Internet Engineering Task Force IETF: Internet Engineering Task Force ������� ������� Comm 2001-2002 Danny Dolev 8

� � � � � � � � � � � � � � � � � � � � � � � � � 3/ What � s the Internet: a service view communication communication infrastructure infrastructure enables enables distributed applications: distributed applications: WWW, email, games, e-commerce, WWW, email, games, e-commerce, database., voting, database., voting, more? more? communication services provided: communication services provided: connectionless connectionless connection-oriented connection-oriented cyberspace [Gibson]: cyberspace [Gibson]: � a consensual hallucination experienced daily by billions of a consensual hallucination experienced daily by billions of operators, in every nation, ...." operators, in every nation, ...." Comm 2001-2002 Danny Dolev 9 What � s a protocol? network protocols: human protocols: human protocols: network protocols: machines rather than humans � what what � � s the time? s the time? � machines rather than humans � � � I have a question I have a question � all communication activity in all communication activity in � � Internet governed by protocols Internet governed by protocols introductions introductions … specific … specific msgs msgs sent sent … specific actions taken when … specific actions taken when msgs msgs received, or other events received, or other events protocols define format, order of protocols define format, order of msgs msgs sent sent and received among network entities, and received among network entities, and actions taken on msg msg transmission, transmission, and actions taken on receipt receipt Comm 2001-2002 Danny Dolev 10

✁ ✁ � � ✁ ✁ ✁ ✁ � � 3/ What � s a protocol? a human protocol and a computer network protocol: a human protocol and a computer network protocol: �� �������������� ����� �� �������������� ������� ������ ����� �✂✁☎✄✝✆✞✄✟✄✟✠✞✡ ☛☞☛☞✌✎✍☎✏ ✍☎✑ ✒✔✓☎✑ ✕✗✖✘✍☞✓☞✓☎✑ ✁✞✙✚✕✗☛✎✏ ✛✟✙✜✁☎✢✣✑ ✆✞✄☞✖ ���� ������ ���� Comm 2001-2002 Danny Dolev 11 A closer look at network structure: network edge: network edge: applications and applications and hosts hosts network core: network core: routers routers network of networks network of networks access networks, physical access networks, physical media: media: communication links communication links Comm 2001-2002 Danny Dolev 12