computer networking lesson

Computer Networking Yishay Mansour (mansour@cs.tau.ac.il) Nir Andelman (http://www.cs.tau.ac.il/~andelmni) Course Information Lectures: Tuesday 9-12 Exercises: Wendsday 10-11 Web site: http://www.cs.tau.ac.il/~andelmni/courses/comnet05/ An Engineering Approach to Computer Networking / Keshav Computer Networks / Tanenbaum Data Networks / Bertsekas and Gallager A Top-down Approach to Computer Networking / Kurouse-Ross Books: Practical Information Homework assignment: Mandatory Both theoretical and programming Done in pairs Grades: Final Exam: 60% February 5 and October 18 theory exercises: 20% Programming exercises: 20% Motivation  Today’s economy  manufacturing, distributing, and retailing goods  but also creating and disseminating information  publishing  banking  film making…. part of the ‘information economy’  Future economy is likely to be dominated by information! Information?  A representation of knowledge  Examples:  books  bills  CDs  Can be represented in two ways  analog (atoms)  digital (bits)  the Digital Revolution  convert information as atoms to information as bits  use networks to move bits around instead of atoms The Challenges  represent all types of information as bits.  move the bits  In large quantities ,  everywhere,  cheaply ,  Securely,  with quality of service,  …. Today’s Networks are complex!  hosts  routers  links of various media  applications  protocols  hardware, software Tomorrow’s will be even more! This course’s Challenge  To discuss this complexity in an organized way, that will make today’s computer networks (and their limitations) more comprehensive.  identification, and understanding relationship of complex system’s pieces.  Problems that are beyond a specific technology Early communications systems  I.e. telephone  point-to-point links  directly connect together the users wishing to communicate  use dedicated communication circuit  if distance between users increases beyond the length of the cable, the connection is formed by a number of sections connected end-to-end in series. Data Networks  set of interconnected nodes exchange information  sharing of the transmission circuits= "switching".  many links allow more than one path between every 2 nodes.  network must select an appropriate path for each required connection. [...].. .Networking Issues - Telephone Addressing - identify the end user phone number 1-201-222-2673 = country code + city code + exchange + number Routing - How to get from source to destination Telephone circuit switching: Based on the phone number Information Units - How is information sent telephone Samples @ Fixed sampling rate not self descriptive! have to know where and when a sample came Networking. .. History 1972-1980: Internetworking, new and proprietary nets 1970: ALOHAnet satellite network in Hawaii 1973: Metcalfe’s PhD thesis proposes Ethernet 1974: Cerf and Kahn - architecture for interconnecting networks late70’s: proprietary architectures: DECnet, SNA, XNA late 70’s: switching fixed length packets (ATM precursor) 1979: ARPAnet has 200 nodes :Cerf and Kahn’s internetworking principles   . http://www.cs.tau.ac.il/~andelmni/courses/comnet05/ An Engineering Approach to Computer Networking / Keshav Computer Networks / Tanenbaum Data Networks / Bertsekas and Gallager A Top-down Approach to Computer Networking / Kurouse-Ross Books: . Computer Networking Yishay Mansour (mansour@cs.tau.ac.il) Nir Andelman (http://www.cs.tau.ac.il/~andelmni) . course’s Challenge  To discuss this complexity in an organized way, that will make today’s computer networks (and their limitations) more comprehensive.  identification, and understanding