* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download EECS 122 Communications Networks
Survey
Document related concepts
Net neutrality law wikipedia , lookup
Deep packet inspection wikipedia , lookup
Asynchronous Transfer Mode wikipedia , lookup
Distributed firewall wikipedia , lookup
Recursive InterNetwork Architecture (RINA) wikipedia , lookup
Zero-configuration networking wikipedia , lookup
Wake-on-LAN wikipedia , lookup
Computer network wikipedia , lookup
Network tap wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Peer-to-peer wikipedia , lookup
Transcript
TOC: Introduction Network Examples Network Components Ethernet Interconnected LANs Internetwork Types of Networks Internet Packets Transport EECS122 - UCB 13 Introduction: Network Examples UCB Backbone: Teleglobe Global Crossing Williams Regional: Palo Alto Types of Networks Internet Packets Transport EECS122 - UCB 14 Network Examples: UCB SODA E3 BACKBONE 2nd Floor Cory E1 E2 1st Floor Cory REGIONAL LOCAL EECS122 - UCB CAMPUS EVANS 15 Network Examples: Backbone Teleglobe Communications Corporation – Fiber + Satellite EECS122 - UCB 16 Network Examples: Backbone Global Crossing Corporation EECS122 - UCB 17 Network Examples: Backbone Williams Communications EECS122 - UCB 18 Network Examples: Regional Palo Alto Network EECS122 - UCB 19 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 EECS122 - UCB 20 Network Components: Links Fibers Cat5 Unshielded Twisted Pairs Coaxial Cable Wireless EECS122 - UCB 21 Network Components: NIC Ethernet Network Interface Card EECS122 - UCB 22 Network Components Telephone Switch EECS122 - UCB Large Router 23 Introduction: Ethernet Ethernet is a Local Area Network (LAN) • Architecture: Switch and/or Hub • System View: Services EECS122 - UCB 24 Ethernet: Architecture Switch and/or Hub: EECS122 - UCB 25 Ethernet: System View Ethernet is a broadcast-capable, multi-access LAN Provides a “Link” service between nodes Abstract view: EECS122 - UCB 26 Introduction: Interconnected LANs LANs interconnected by routers LAN2 LAN1 R1 LAN3 EECS122 - UCB R3 R2 R4 Internet 27 Introduction: Internetwork Provides message delivery between multiple networks that may belong to different organizations: ISP 1 Subnet 1 ISP 2 Subnet 2 Example: Subnet 1 = network of LANs of previous slide ISP 1 = Sprint, ISP 2 = MCI Subnet 2 = UCB network EECS122 - UCB 28 Introduction: Types of Network Classification 1: Size, Information, Application Classification 2: Use, Protocols, Technologies Switching Broadcast vs. Switched Characteristics How to switch Taxonomy EECS122 - UCB 29 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 General purpose network: Internet network, banking network, credit card network, telephony, CATV EECS122 - UCB 30 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 EECS122 - UCB 31 Types of Network: Broadcast vs. Switched Broadcast Network: Switched Network: EECS122 - UCB 32 Types of Network: Characteristics 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 EECS122 - UCB 33 Types of Network: How to Switch? Circuit-Switched: 1. 2. 3. Set up circuit between two devices Exchange information Release circuit Packet-Switched: Send packets with source and destination addresses Vircuit-Circuit Switched: 1. 2. 3. 4. 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.} EECS122 - UCB 34 Types of Network: Taxonomy Based on the way in which the nodes exchange information: Switched Circuit Telephone EECS122 - UCB Virtual Circuit MPLS ATM Frame Relay Broadcast Packet Sw.-Ethernet Internet Hub-Ethernet CATV 35 Introduction: The Internet Overview Scale EECS122 - UCB 36 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 EECS122 - UCB 37 Internet: Scale • Data from www.nw.com EECS122 - UCB 38 Introduction: Packets Illustration Main Ideas EECS122 - UCB 39 Packets: Illustration B 1 A | B | ... 2 3 A B port 2 EECS122 - UCB 40 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 EECS122 - UCB 41 Introduction: Transport Acknowledgments Link Sharing EECS122 - UCB 42 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. EECS122 - UCB 43 Transport: Link Sharing Shared links The sources base their transmissions on when they get acknowledgments. The scheme regulates the sharing of common links EECS122 - UCB 44