introduction.ppt

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introduction.ppt

  1. 1. EECS122 - UCB 1 TOC: Introduction Network Examples Network Components Ethernet Interconnected LANs Internetwork Types of Networks Internet Packets Transport
  2. 2. EECS122 - UCB 2 Introduction: Network Examples UCB Backbone:  Teleglobe  Global Crossing  Williams Regional: Palo Alto Types of Networks Internet Packets Transport
  3. 3. EECS122 - UCB 3 Network Examples: UCB E1 E2 E3 REGIONAL 1st Floor Cory 2nd Floor Cory SODA EVANS BACKBONE CAMPUS LOCAL
  4. 4. EECS122 - UCB 4 Network Examples: Backbone Teleglobe Communications Corporation – Fiber + Satellite
  5. 5. EECS122 - UCB 5 Network Examples: Backbone Global Crossing Corporation
  6. 6. EECS122 - UCB 6 Network Examples: Backbone Williams Communications
  7. 7. EECS122 - UCB 7 Network Examples: Regional Palo Alto Network
  8. 8. EECS122 - UCB 8 Introduction: Network Components Links: carry bits from one place to another (or maybe to many other places) Interface: attaches device to link Switch/router: interconnect links Host: communication endpoint (workstation, PDA, cell phone, toaster, tank) – connected to links
  9. 9. EECS122 - UCB 9 Network Components: Links Fibers Cat5 Unshielded Twisted Pairs Coaxial Cable Wireless
  10. 10. EECS122 - UCB 10 Network Components: NIC Ethernet Network Interface Card
  11. 11. EECS122 - UCB 11 Network Components Telephone Switch Large Router
  12. 12. EECS122 - UCB 12 Introduction: Ethernet Ethernet is a Local Area Network (LAN) • Architecture: Switch and/or Hub • System View: Services
  13. 13. EECS122 - UCB 13 Ethernet: Architecture Switch and/or Hub:
  14. 14. EECS122 - UCB 14 Ethernet: System View Ethernet is a broadcast-capable, multi- access LAN Provides a “Link” service between nodes Abstract view:
  15. 15. EECS122 - UCB 15 Introduction: Interconnected LANs LANs interconnected by routers LAN1 LAN2 LAN3 Internet R1 R2 R3 R4
  16. 16. EECS122 - UCB 16 Introduction: Internetwork Provides message delivery between multiple networks that may belong to different organizations: Subnet 1 Subnet 2 ISP 2ISP 1 Example: Subnet 1 = network of LANs of previous slide ISP 1 = Sprint, ISP 2 = MCI Subnet 2 = UCB network
  17. 17. EECS122 - UCB 17 Introduction: Types of Network Classification 1: Size, Information, Application Classification 2: Use, Protocols, Technologies Switching  Broadcast vs. Switched  Characteristics  How to switch  Taxonomy
  18. 18. EECS122 - UCB 18 Types of Network: Classification 1 Geographical distance  Local Area Networks (LAN): Ethernet, Token ring, FDDI  Metropolitan Area Networks (MAN): DQDB, SMDS  Wide Area Networks (WAN): X.25, ATM, frame relay  Caveat: LAN, MAN, WAN may mean different things: Service, network technology, networks Information type  Data networks vs. telecommunication networks Application type  Special purpose networks: airline reservation network, banking network, credit card network, telephony, CATV  General purpose network: Internet
  19. 19. EECS122 - UCB 19 Types of Network: Classification 2 Right to use  Private: enterprise networks  Public: telephony network, Internet Protocols:  Proprietary: SNA, AppleTalk  Open: IP Technologies  Terrestrial vs. satellite  Wired vs. wireless
  20. 20. EECS122 - UCB 20 Broadcast Network: Types of Network: Broadcast vs. Switched Switched Network:
  21. 21. EECS122 - UCB 21 Broadcast  One to all  Examples: some LANs (Hub-Ethernet, 802.11)  Problem: coordinate the access of all nodes to the shared communication medium (Multiple Access Problem) Switched  One to subset  Examples: WANs (Telephony Network, Internet)  Problem: how to forward information to intended node(s)  This is done by special nodes (e.g., routers, switches) running routing protocols Types of Network: Characteristics
  22. 22. EECS122 - UCB 22 Circuit-Switched: 1. Set up circuit between two devices 2. Exchange information 3. Release circuit Packet-Switched:  Send packets with source and destination addresses Vircuit-Circuit Switched: 1. Select path from source to destination (Virtual Circuit) 2. Assign a “label” to that path 3. Send packets with that label 4. Release Virtual Circuit {Note: Some VCs are permanent.} Types of Network: How to Switch?
  23. 23. EECS122 - UCB 23 Based on the way in which the nodes exchange information: Types of Network: Taxonomy Switched Broadcast Circuit Packet Virtual Circuit Telephone MPLS ATM Frame Relay Sw.-Ethernet Internet Hub-Ethernet CATV
  24. 24. EECS122 - UCB 24 Introduction: The Internet Overview Scale
  25. 25. EECS122 - UCB 25 Internet: Overview A global network of networks all using a common protocol (IP, the Internet Protocol) Focus of this class A challenge to understand:  large scale (10’s of millions of users, 10’s of thousands of networks)  heterogeneity, irregular topology, decentralized management
  26. 26. EECS122 - UCB 26 Internet: Scale • Data from www.nw.com
  27. 27. EECS122 - UCB 27 Introduction: Packets Illustration Main Ideas
  28. 28. EECS122 - UCB 28 Packets: Illustration A B B → port 2 1 2 3 A | B | ...
  29. 29. EECS122 - UCB 29 Packets: Main Ideas The switches have no memory of packets: scalability The network is independent of the applications: flexibility The packet formats and addresses are independent of the technology: extensibility
  30. 30. EECS122 - UCB 30 Introduction: Transport Acknowledgments Link Sharing
  31. 31. EECS122 - UCB 31 Transport: Acknowledgments The destination sends back an acknowledgment for every correct packet it gets. The source uses these ACKs to - Retransmit unacknowledged packets - Adjust the rate of its transmissions. The destination sends back an acknowledgment for every correct packet it gets. The source uses these ACKs to - Retransmit unacknowledged packets - Adjust the rate of its transmissions.
  32. 32. EECS122 - UCB 32 Transport: Link Sharing Shared links The sources base their transmissions on when they get acknowledgments. The scheme regulates the sharing of common links The sources base their transmissions on when they get acknowledgments. The scheme regulates the sharing of common links

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