EECS122 - UCB13 TOCTOC: Introduction Network Examples Network Components Ethernet Interconnected LANs Internetwork Types of Networks Internet Packets Transport

EECS122 - UCB14 IntroductionIntroduction: Network Examples UCB Backbone: Teleglobe Global Crossing Williams Regional: Palo Alto Types of Networks Internet Packets Transport

EECS122 - UCB15 Network Examples Network Examples : UCB E1 E2 E3 REGIONAL 1 st Floor Cory 2 nd Floor Cory SODA EVANS BACKBONE CAMPUS LOCAL

EECS122 - UCB16 Network ExamplesNetwork Examples: Backbone TeleglobeTeleglobe Communications Corporation – Fiber + Satellite

EECS122 - UCB17 Network ExamplesNetwork Examples: Backbone Global Crossing Corporation

EECS122 - UCB18 Network ExamplesNetwork Examples: Backbone Williams Communications

EECS122 - UCB19 Network ExamplesNetwork Examples: Regional Palo Alto Network

EECS122 - UCB20 IntroductionIntroduction: Network Components LinksLinks: carry bits from one place to another (or maybe to many other places) InterfaceInterface: attaches device to link Switch/routerSwitch/router: interconnect links Host: communication endpoint (workstation, PDA, cell phone, toaster, tank) – connected to links

EECS122 - UCB21 Network ComponentsNetwork Components: Links Fibers Cat5 Unshielded Twisted Pairs Coaxial Cable Wireless

EECS122 - UCB22 Network ComponentsNetwork Components: NIC Ethernet Network Interface Card

EECS122 - UCB23 Network Components Telephone SwitchLarge Router

EECS122 - UCB24 IntroductionIntroduction: Ethernet Ethernet is a Local Area Network (LAN) Architecture: Switch and/or HubArchitecture System View: ServicesSystem View

EECS122 - UCB25 EthernetEthernet: Architecture Switch and/or Hub:

EECS122 - UCB26 EthernetEthernet: System View Ethernet is a broadcast-capable, multi-access LAN Provides a “Link” service between nodes Abstract view:

EECS122 - UCB27 IntroductionIntroduction: Interconnected LANs LANs interconnected by routers LAN1 LAN2 LAN3 Internet R1 R2 R3 R4

EECS122 - UCB28 IntroductionIntroduction: Internetwork Provides message delivery between multiple networks that may belong to different organizations: Subnet 1 Subnet 2 ISP 2 ISP 1 Example: Subnet 1 = network of LANs of previous slide ISP 1 = Sprint, ISP 2 = MCI Subnet 2 = UCB network

EECS122 - UCB29 IntroductionIntroduction: Types of Network ClassificationClassification 1: Size, Information, Application ClassificationClassification 2: Use, Protocols, Technologies Switching Broadcast vs. Switched Characteristics How to switch Taxonomy

EECS122 - UCB30 Types of NetworkTypes 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

EECS122 - UCB31 Types of NetworkTypes 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

EECS122 - UCB32 Broadcast Network: Types of NetworkTypes of Network: Broadcast vs. Switched Switched Network:

EECS122 - UCB33 Broadcast One to all Examples: some LANs (Hub-Ethernet, ) 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 NetworkTypes of Network: Characteristics

EECS122 - UCB34 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 NetworkTypes of Network: How to Switch?

EECS122 - UCB35 Based on the way in which the nodes exchange information: Types of NetworkTypes of Network: Taxonomy Switched Broadcast CircuitPacket Virtual Circuit TelephoneMPLS ATM Frame Relay Sw.-Ethernet Internet Hub-Ethernet CATV

EECS122 - UCB36 IntroductionIntroduction: The Internet Overview Scale

EECS122 - UCB37 InternetInternet: 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

EECS122 - UCB38 InternetInternet: Scale Data from

EECS122 - UCB39 IntroductionIntroduction: Packets Illustration Main Ideas

EECS122 - UCB40 PacketsPackets: Illustration A B B  port A | B |...

EECS122 - UCB41 PacketsPackets: 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

EECS122 - UCB42 IntroductionIntroduction: Transport Acknowledgments Link Sharing

EECS122 - UCB43 TransportTransport: Acknowledgments The destination sends back an acknowledgment for every correct packet it gets. The source uses these ACKs to - Retransmit unacknowledged packets Retransmit unacknowledged packets - Adjust the rate of its transmissions. 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 Retransmit unacknowledged packets - Adjust the rate of its transmissions. Adjust the rate of its transmissions.

EECS122 - UCB44 TransportTransport: 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