TOC: Introduction

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TOC Introduction

• Network Examples
• Network Components
• Ethernet
• Interconnected LANs
• Internetwork
• Types of Networks
• Internet
• Packets
• Transport

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Introduction Network Examples

• UCB
• Backbone
• Teleglobe
• Global Crossing
• Williams
• Regional Palo Alto
• Types of Networks
• Internet
• Packets
• Transport

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Network Examples UCB
BACKBONE
SODA
2nd Floor Cory
1st Floor Cory
REGIONAL
EVANS
LOCAL
CAMPUS
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Network Examples Backbone
Teleglobe Communications Corporation Fiber
Satellite
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Network Examples Backbone
Global Crossing Corporation
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Network Examples Backbone
Williams Communications
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Network Examples Regional
Palo Alto Network
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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 link
• Switch/router interconnect links
• Host communication endpoint (workstation, PDA,
  cell phone, toaster, tank) connected to links

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Network Components Links
Fibers
Cat5 Unshielded Twisted Pairs
Coaxial Cable
Wireless
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Network Components NIC
Ethernet Network Interface Card
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Network Components
Telephone Switch
Large Router
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Introduction Ethernet

• Ethernet is a Local Area Network (LAN)
• Architecture Switch and/or Hub
• System View Services

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Ethernet Architecture
Switch and/or Hub
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Ethernet System View

• Ethernet is a broadcast-capable, multi-access LAN
• Provides a Link service between nodes
• Abstract view

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Introduction Interconnected LANs
LANs interconnected by routers
LAN2
LAN1
R1
R2
Internet
LAN3
R4
R3
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Introduction Internetwork

• Provides message delivery between multiple
  networks that may belong to different
  organizations

ISP 2
ISP 1
Subnet 2
Subnet 1
Example Subnet 1 network of LANs of
previous slide ISP 1 Sprint, ISP 2
MCI Subnet 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 use
• Private enterprise networks
• Public telephony network, Internet
• Protocols
• Proprietary SNA, AppleTalk
• Open IP
• Technologies
• Terrestrial vs. satellite
• Wired vs. wireless

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Types of Network Broadcast vs. Switched

• Broadcast Network

• Switched Network

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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

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Types of Network How to Switch?

• Circuit-Switched
• Set up circuit between two devices
• Exchange information
• Release circuit
• Packet-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.

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Types of Network Taxonomy

• Based on the way in which the nodes exchange
  information

Hub-Ethernet CATV
Telephone
MPLS ATM Frame Relay
Sw.-Ethernet Internet
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Introduction The Internet

• Overview
• Scale

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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 (10s of millions of users, 10s of
  thousands of networks)
• heterogeneity, irregular topology, decentralized
  management

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Internet Scale

• Data from www.nw.com

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Introduction Packets

• Illustration
• Main Ideas

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Packets Illustration
A B ...
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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

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Introduction Transport

• Acknowledgments
• Link Sharing

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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.

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Transport Link Sharing
The sources base their transmissions on when they
get acknowledgments. The scheme regulates the
sharing of common links