Ch 1 Computer Networks and the Internet

Nuts and Bolts Description

Basic hardware and software components that make up the internet

Hosts End Systems

Computers and other Non traditional devices that are being hooked up to the internet

Protocol

Defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event

Protocols in Routers

Determine a packets path from source to destination

Internet standards

Developed by the internet engineering task force, given the importance of protocols to the internet, it is important that everyone agree on what each and every protocol does, so that people can create systems and products that inter-operate

Human Protocol

Dictates that one must first offer a greeting to initiate communication with someone else, there are specific messages we send, and specific actions we take in response to the received reply messages or other events

Transmission Rate

Different links can transmit data at different rates, link measured in bits/second

Internet service providers (ISPs)

End systems access the internet, including residential, corporate, university, provide WiFi access in airports, hotels, coffee shops, and other public places, and cellular data ISPs

Communication Links and Packet Switches

End systems are connected together by a network of

Socket Interface

End systems attached to the internet provide, specifies how a program running on one end system asks the internet infrastructure to deliver data to a specific destination program running on another end system

Network Protocol

Entities exchanging messages and taking actions are hardware or software components of some device

Congestion control protocols

Found in End systems, control the rate at which packets are transmitted between sender and receiver

Hardware implemented Protocols

Found in Two physically connected computers, control the flow of bits on the wire between the two network interface cards

Clients and Servers

Hosts are sometimes further divided into two subcategories

Request for comments (RFCs)

IETF standards documents, started out as general requests for comments to resolve network and protocol design problems that faced the precursor to the internet

Services Description

Infrastructure that provides services to applications

Distributed Applications

Involve multiple end systems that exchange data with each other

Residential ISPs

Local cable or telephone companies

Communication Links

Made up of different types of physical media, including coaxial, cable, copper wire, optical fiber, and radio spectrum

Access Network

Network that physically connects an end system to the first router on a path from the end system to any other distant end system

Internet

Networking infrastructure that provides services to distributed applications

Cellular data ISPs

Providing mobile access to our smart phones and other devices

Packets

Resulting packages of information, then sent through the network to the destination end system, where they are reassembled into original data

Hosts

Run application programs such as web browser program, a web server program, an email client program, or an email server program

Route or Path

Sequence of communication links and packet switches traversed by a packet from the sending end system to the receiving end system, through the network

IP Protocol

Specifies the format of the packets that are sent and received among routers and end systems

Packet switch

Takes a packet arriving on one of its incoming communication links and forwards that packet on one of its outgoing communication links

Networking

Takes two or more communicating entities running the same protocol in order to accomplish a task

Clients

Tend to be Desk tops and mobile PCs, smart phones, and so on

Servers

Tend to be more powerful machines that store and distribute web pages, stream video, relay email, and so on

Data centers

Today, Most of the servers from which we receive search results, email, webpages, and videos reside in large

Digital subscriber line (DSL) and Cable

Two most prevalent types of broadband residential access

Routers and link layer switches

Two most prominent types in today's internet, forward packets toward their ultimate destinations

Transmission Control Protocol (TCP) and the Internet Protocol (IP), TCP/IP

Two of the most important protocols in the internet, internet principle protocols

Link layer switches

Typically used in access networks

Routers

Typically used in the network core