Networking and Internetworking i206 Fall 2010 John Chuang.

Networking and Internetworking

i206 Fall 2010

John Chuang

John Chuang IS206 UC Berkeley 2

Network

Bits & BytesBinary Numbers

Number Systems

Gates

Boolean Logic

Circuits

CPU Machine Instructions

Assembly Instructions

Program Algorithms

Application

Memory

Data compression

Compiler/Interpreter

OperatingSystem

Data Structures

Analysis

I/O

Memory hierarchy

Design

Methodologies/Tools

Process

Truth tableVenn DiagramDeMorgan’s Law

Numbers, text,audio, video, image, …

Decimal, Hexadecimal, Binary

AND, OR, NOT, XOR, NAND, NOR,etc.

Register, CacheMain Memory,Secondary Storage

Context switchProcess vs. ThreadLocks and deadlocks

Op-code, operandsInstruction set arch

Lossless v. lossyInfo entropy & Huffman code Adders, decoders,

Memory latches, ALUs, etc.

DataRepresentation

Data

Data storage

Principles

ALUs, Registers,Program Counter, Instruction Register

Network

Distributed Systems Security

Cryptography

Standards & Protocols

Inter-processCommunication

Searching, sorting,Encryption, etc.

Stacks, queues,maps, trees, graphs, …

Big-O

UML, CRC

TCP/IP, RSA, …

ConfidentialityIntegrityAuthentication…

C/S, P2PCaching

sockets

Formal models

Finite automataregex

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Lecture Outline

Different abstractions of a network

Network architecture- Layered protocol architecture- Message encapsulation

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Network as Communication Channel

process p process q

Communication channel

send

Outgoing message buffer Incoming message buffer

receivem

Source: Coulouris, Dollimore and Kindberg

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Network Cloud

Network utility: ping

client server

Network

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Network: Routers & Links

Hosts Linksor local networks

A

D E

B

C

1

2

5

43

6

Routers

Network utility: traceroute/tracert

Source: Coulouris, Dollimore and Kindberg

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LocalExchangeCarrier(LEC) Router

ISP

BackboneProvider 1

Router

Client

TandemSwitch

Inter-exchangeCarrier (IXC) Long-

Distance Network

Corporate LAN

Firewall

AnalogModem

ContentProvider

Server

Router

Remote ISP

Point of Presence

xDSLModem

CableModem

Packet Network HeadendCable ISP

LocalLoop

DNS

Local Ingress Switch

Exchange Point

Router

Internet Service ProvidersCustomer Premises

Internet backbonesTelephone Network

Local Egress Switch

BackboneProvider 2

router

Mobile Client

Wireless ISP

Network: More Details

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Network Types

Range Bandwidth (Mbps)Latency (ms)

LAN 1-2 kms 10-1000 1-10WAN worldwide0.010-600 100-500MAN 2-50 kms 1-150 10

Wireless LAN0.15-1.5 km2-11 5-20Wireless WANworldwide0.010-2 100-500Internet worldwide0.010-2 100-500

An internet: a set of interconnected networks The Internet: the global internetwork based upon

the Internet Protocol (IP)

Source: Coulouris, Dollimore and Kindberg

circa 2000

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Network Building Blocks

Transmission media- Copper (coax, twisted pair), optical fiber, free space (wireless)

Signals- Electrical currents, light, RF (radio-frequency), microwave

Hardware devices- End hosts, network interfaces- Routers, switches, hubs, bridges, repeaters

Software components- Communication protocol stack

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Lecture Outline

Different abstractions of a network

Network architecture- Layered protocol architecture- Message encapsulation

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Network Architecture

Networking can be quite complex and requires a high degree of cooperation between the involved parties.

Cooperation is achieved by forcing parties to adhere to a set of rules and conventions (protocol).

The complexity of the communication task is reduced by using multiple protocol layers:

- Each layer is implemented independently.- Each layer is responsible for a specific subtask.- Layers are grouped in a hierarchy.

A structured set of protocols is called a network architecture, protocol architecture, or protocol suite.

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What each layer does

Application (layer 7): specific to application need

Presentation (layer 6): conversion of data representation

Session (layer 5): access mgt, synchronization

Transport (layer 4): end-to-end delivery, congestion and flow control

Network (layer 3): addressing, routing

Data Link (layer 2): framing, error detection

Physical (layer 1): bits (0/1), voltages, frequencies, wires, pins, …

Application layer

Presentation layer

Session layer

Transport layer

Network layer

Data link layer

Physical layer

Layer 1

Layer 2

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

ISO/OSI Reference Model

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Layered Protocol Architecture

Application layer

Transport layer

Network layer

Link layer

TCP/IP Model

Physical layerLayer 1

Layer 2

Layer 7

Layer 4

Layer 3

Software

OperatingSystem

Hardware

Application layer

Presentation layer

Session layer

Transport layer

Network layer

Data link layer

Physical layer

Layer 1

Layer 2

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

ISO/OSI Reference Model

Socket API

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The “IP Hourglass”

IP

TCP, UDP

HTTP, FTP, SSH, SMTP,Your python program, ...

coax, twisted pair, fiber,wireless, pigeons, ...

Ethernet,WiFi, SONET

Physical Layer

Data Link Layer

Network Layer

Transport Layer

Application Layer

A single protocol

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TCP/IP ModelAppl

Transport

Network

Link

Network

Link

Network

Link

Appl

Transport

Network

Link

Host A Host BRouter 1 Router 2

end-to-end

point-to-point

point-to-point

end-to-end

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TCP/IP ModelAppl

Transport

Network

Link

Network

Link

Network

Link

Appl

Transport

Network

Link

Host A Host BRouter 1 Router 2

end-to-end

point-to-point

point-to-point

end-to-end

client server(ping)

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TCP/IP ModelAppl

Transport

Network

Link

Network

Link

Network

Link

Appl

Transport

Network

Link

Host A Host BRouter 1 Router 2

end-to-end

point-to-point

point-to-point

end-to-end

(traceroute)

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Message FlowAppl

Transport

Network

Link

Network

Link

Network

Link

Appl

Transport

Network

Link

Host A Host BRouter 1 Router 2

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Encapsulation Example: Sending HTTP message using TCP/IP over Ethernet

HTTP message

TCP header

IP header

Ethernet header

Ethernet frame

port

TCP

IP IP datagram/packet

TCP segment

HTTP message

Adapted from Coulouris, Dollimore and Kindberg

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EncapsulationAppl

Transport

Network

Link

Network

Link

Network

Link

Appl

Transport

Network

Link

Host A Host BRouter 1 Router 2

Data

Data

Data

Data

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Summary

Layering:- Hourglass: many different applications and underlying network technologies, but Internet Protocol establishes universal addressing scheme

- Envelope/Encapsulation: layer-specific functionalities; isolation between layers

Reliable communication over unreliable network- IP provides “best-effort” packet delivery service

- TCP supports retransmission of lost packets