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Introduction1-1 Course Code:EE/TE533 Instructor: Muddathir Qamar.

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Presentation on theme: "Introduction1-1 Course Code:EE/TE533 Instructor: Muddathir Qamar."— Presentation transcript:

1 Introduction1-1 Course Code:EE/TE533 Instructor: Muddathir Qamar

2 Introduction1-2 Reference Books: Computer Networking : A Top-Down Approach Featuring the Internet (3rd Edition) by James F. Kurose, Keith W. Ross RTP: Audio and Video for the Internet by Colin Perkins

3 Introduction1-3 Brief Outline: Introduction, Internet Protocols & Network Core, Internet Backbone and access, Networking Applications Multicast, Multimedia Networking & Properties of Real-Time Services –RTP Internet Telephony H.323, SIP, ENUM, SoftswitchQOS (Resource Reservation, Differentiated Services and MPLS) (Midterm)Local Area Networks, Optical Networks (Ethernet/Wireless/Sonet) Access TechnologiesWireless and Mobility Storage Area Network / Metro EthernetPOS/ FTTH/ Web- CachingSecurity, Firewall, Intrusion Prevention E-BusinessStudent Presentations

4 Introduction1-4 Chapter 1: Introduction Overview:  what’s the Internet  what’s a protocol?  network edge  network core  Internet/ISP structure

5 Introduction1-5 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Internet structure and ISPs 1.5 Protocol layers, service models 1.8 History

6 Introduction1-6 What’s the Internet:  millions of connected computing devices: hosts = end systems  running network apps  communication links m fiber, copper, radio, satellite m transmission rate = bandwidth  routers: forward packets (chunks of data) local ISP company network regional ISP router workstation server mobile

7 Introduction1-7 What’s the Internet:  protocols control sending, receiving of msgs m e.g., TCP, IP, HTTP, FTP, PPP  Internet: “network of networks” m loosely hierarchical m public Internet versus private intranet  Internet standards m RFC: Request for comments m IETF: Internet Engineering Task Force local ISP company network regional ISP router workstation server mobile

8 Introduction1-8 What’s the Internet: a service view  communication infrastructure enables distributed applications: m Web, email, games, e- commerce, file sharing  communication services provided to apps: m Connectionless unreliable m connection-oriented reliable

9 Introduction1-9 What’s a protocol? human protocols:  “what’s the time?”  “I have a question”  introductions … specific msgs sent … specific actions taken when msgs received, or other events network protocols:  machines rather than humans  all communication activity in Internet governed by protocols protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt

10 Introduction1-10 What’s a protocol? a human protocol and a computer network protocol: Q: Other human protocols? Hi Got the time? 2:00 TCP connection req TCP connection response Get http://www.awl.com/kurose-ross time

11 Introduction1-11 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Internet structure and ISPs

12 Introduction1-12 Network structure:  network edge: applications and hosts  network core: m routers m network of networks  access networks, physical media: communication links

13 Introduction1-13 The network edge:  end systems (hosts): m run application programs m e.g. Web, email m at “edge of network”  client/server model m client host requests, receives service from always-on server m e.g. Web browser/server; email client/server  peer-peer model: m minimal (or no) use of dedicated servers m e.g. Gnutella, KaZaA

14 Introduction1-14 Connection-oriented service Goal: data transfer between end systems  handshaking: setup (prepare for) data transfer ahead of time m Hello, hello back human protocol m set up “state” in two communicating hosts  TCP - Transmission Control Protocol m Internet’s connection- oriented service TCP service [RFC 793]  reliable, in-order byte- stream data transfer m loss: acknowledgements and retransmissions  flow control: m sender won’t overwhelm receiver  congestion control: m senders “slow down sending rate” when network congested

15 Introduction1-15 Connectionless service Goal: data transfer between end systems m same as before!  UDP - User Datagram Protocol [RFC 768]: m connectionless m unreliable data transfer m no flow control m no congestion control App’s using TCP:  HTTP (Web), FTP (file transfer), Telnet (remote login), SMTP (email) App’s using UDP:  streaming media, teleconferencing, DNS, Internet telephony

16 Introduction1-16 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge 1.3 Network core 1.4 Network access and physical media 1.5 Internet structure and ISPs 1.6 Delay & loss in packet-switched networks 1.7 Protocol layers, service models 1.8 History

17 Introduction1-17 The Network Core  mesh of interconnected routers  the fundamental question: how is data transferred through net? m circuit switching: dedicated circuit per call: telephone net m packet-switching: data sent thru net in discrete “chunks”

18 Introduction1-18 Network Core: Circuit Switching End-end resources reserved for “call”  link bandwidth, switch capacity  dedicated resources: no sharing  circuit-like (guaranteed) performance  call setup required

19 Introduction1-19 Network Core: Circuit Switching network resources (e.g., bandwidth) divided into “pieces”  pieces allocated to calls  resource piece idle if not used by owning call (no sharing)  dividing link bandwidth into “pieces” m frequency division m time division

20 Introduction1-20 Circuit Switching: FDM and TDM FDM frequency time TDM frequency time 4 users Example:

21 Introduction1-21 Network Taxonomy Telecommunication networks Circuit-switched networks FDM TDM Packet-switched networks Networks with VCs Datagram Networks Datagram network is not either connection-oriented or connectionless. Internet provides both connection-oriented (TCP) and connectionless services (UDP) to apps.

22 Introduction1-22 Internet structure: network of networks  roughly hierarchical  at center: “tier-1” ISPs (e.g., UUNet, BBN/Genuity, Sprint, AT&T), national/international coverage m treat each other as equals Tier 1 ISP Tier-1 providers interconnect (peer) privately NAP Tier-1 providers also interconnect at public network access points (NAPs)

23 Introduction1-23 Tier-1 ISP: e.g., Sprint Sprint US backbone network

24 Introduction1-24 Internet structure: network of networks  “Tier-2” ISPs: smaller (often regional) ISPs m Connect to one or more tier-1 ISPs, possibly other tier-2 ISPs Tier 1 ISP NAP Tier-2 ISP Tier-2 ISP pays tier-1 ISP for connectivity to rest of Internet  tier-2 ISP is customer of tier-1 provider Tier-2 ISPs also peer privately with each other, interconnect at NAP

25 Introduction1-25 Internet structure: network of networks  “Tier-3” ISPs and local ISPs m last hop (“access”) network (closest to end systems) Tier 1 ISP NAP Tier-2 ISP local ISP local ISP local ISP local ISP local ISP Tier 3 ISP local ISP local ISP local ISP Local and tier- 3 ISPs are customers of higher tier ISPs connecting them to rest of Internet

26 Introduction1-26 Internet structure: network of networks  a packet passes through many networks! Tier 1 ISP NAP Tier-2 ISP local ISP local ISP local ISP local ISP local ISP Tier 3 ISP local ISP local ISP local ISP


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