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EECS122 - UCB 1
TOC: IntroductionNetwork ExamplesNetwork Components EthernetInterconnected LANsInternetworkTypes of NetworksInternetPacketsTransport
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Introduction: Network Examples
UCBBackbone: Teleglobe Global Crossing Williams
Regional: Palo AltoTypes of NetworksInternetPacketsTransport
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Network Examples: UCB
E1E2
E3
REGIONAL1st Floor Cory
2nd FloorCory
SODA
EVANS
BACKBONE
CAMPUS
LOCAL
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Network Examples: BackboneGlobal Crossing Corporation
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Network Examples: BackboneWilliams Communications
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Introduction: Network Components
Links: carry bits from one place to another (or maybe to many other places)Interface: attaches device to linkSwitch/router: interconnect linksHost: communication endpoint (workstation, PDA, cell phone, toaster, tank) – connected to links
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Network Components: Links
Fibers
Cat5 UnshieldedTwisted Pairs
Coaxial Cable
Wireless
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Network Components: NIC
Ethernet Network Interface Card
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Network ComponentsTelephone Switch Large Router
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Introduction: EthernetEthernet is a Local Area Network (LAN)
• Architecture: Switch and/or Hub
• System View: Services
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Ethernet: System ViewEthernet is a broadcast-capable, multi-access LANProvides a “Link” service between nodes
Abstract view:
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Introduction: Interconnected LANsLANs interconnected by routers
LAN1
LAN2
LAN3Internet
R1R2
R3 R4
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Introduction: InternetworkProvides message delivery between multiple networks that may belong to different organizations:
Subnet 1Subnet 2
ISP 2ISP 1
Example: Subnet 1 = network of LANs of previous slideISP 1 = Sprint, ISP 2 = MCISubnet 2 = UCB network
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Introduction: Types of Network
Classification 1: Size, Information, Application
Classification 2: Use, Protocols, Technologies
Switching Broadcast vs. Switched Characteristics How to switch Taxonomy
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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
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Types of Network: Classification 2
Right to usePrivate: enterprise networksPublic: telephony network, Internet
Protocols:Proprietary: SNA, AppleTalkOpen: IP
TechnologiesTerrestrial vs. satelliteWired vs. wireless
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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
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Circuit-Switched: 1. Set up circuit between two devices2. Exchange information3. Release circuitPacket-Switched:
Send packets with source and destination addresses
Vircuit-Circuit Switched: Select path from source to destination (Virtual
Circuit) Assign a “label” to that path Send packets with that label Release Virtual Circuit
{Note: Some VCs are permanent.}
Types of Network: How to Switch?
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Based on the way in which the nodes exchange information:
Types of Network: Taxonomy
Switched Broadcast
Circuit PacketVirtualCircuit
Telephone MPLSATMFrame Relay
Sw.-EthernetInternet
Hub-EthernetCATV
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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
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Packets: Main IdeasThe switches have no memory of packets: scalabilityThe network is independent of the applications: flexibilityThe packet formats and addresses are independent of the technology: extensibility
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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.