计算机网络原理(英文版)课件Chapter1-下

Application layer
• • • • • • • 2.1 Principles of network applications 2.2 Web and HTTP 2.3 FTP 2.4 DNS 2.5 P2P file sharing 2.6 Socket programming with TCP 2.7 Socket programming with UDP
P2P software applications include these seven key characteristics:
• the user interface runs outsides of a Web browser • computers in the system can act as both clients and servers • the software is easy to use and well-integrated • the application includes tools to support users wanting to create content or add functionality • the application makes connections with other users • the application does something new or exciting • the software supports "cross-network" protocols like SOAP or XML-RPC
Peer-to-peer
• Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes. • Peers make a portion of their resources, such as processing power, disk storage or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers of resources, in contrast to the traditional client–server model where only servers supply, and clients consume. • The peer-to-peer application structure was popularized by file sharing systems like Napster.

Overview: what’s the Internet what’s a protocol? network edge network rmance: loss, delay protocol layers, service models backbones, NAPs, ISPs history ATM network
1: Introduction 7
The network edge:
end systems (hosts):
run application programs e.g., WWW, email at “edge of network”
client/server model
client host requests, receives service from server
protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt
1: Introduction 5
What’s a protocol?
router server
local ISP
workstation mobile
regional ISP
company network
1: Introduction 3
What’s the Internet: a service view
communication
infrastructure enables
Internet: “network of
networks”
loosely hierarchical

Introduction to Computer Networks
Discover the world of computer networks, from their definition and significance to their classification and protocols. Explore the fascinating concepts of OSI and TCP/IP models, network topologies, devices, security, performance optimization, applications, and management.
Network Performance Optimization
Data Transmission Rate
Learn about factors that influence transmission speeds, such as bandwidth, latency, and throughput.
Star
A network topology where devices are connected to a central hub or switch.
Ring
A network topology where devices are connected in a circular manner, forming a
Reducing Latency
Discover techniques to minimize latency, ensuring faster response times and smoother network performance.
Increasing Bandwidth

Chapter 1
Computer Abstractions and Technology
§1.1 Introduction
The Computer Revolution

Progress in computer technology

Underpinned by Moore’s Law

What is Moore’s Law ???

Assembly language

Textual representation of instructions
Binary digits (bits) Encoded instructions and data
Chapter 1 — Computer Abstractions and Technology — 14
Chapter 1 — Computer Abstractions and Technology — 22
Inside the Processor

AMD Barcelona: 4 processor cores
Chapter 1 — Computer Abstractions and Technology — 23

Programming language, compiler, architecture


Processor and memory system


I/O system (including OS)

Determines how fast I/O operations are executed
Chapter 1 — Computer Abstractions and Technology — 16