Hardware8

P R O T O C O LP R O T O C O L

A protocol is a set of rules that governs the

communications between computers on a network.

These rules include guidelines that regulate the

following characteristics of a network. The most

common protocols are:

o Ethernet o Local Talk o Token Ring o FDDI o ATM

ETHERNET

Ethernet protocol is by far the most widely used.

Ethernet uses an access method called CSMA/CD (Carrier

Sense Multiple Access/Collision Detection).

This is a system where each computer listens to the cable

before sending anything through the network. If the network

is clear, the computer will transmit. If some other node is

already transmitting on the cable, the computer will wait and

try again when the line is clear.

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ETHERNET

If two computers attempt to transmit at the same instant, a collision will occurs. Each computer then backs off and waits a random amount of time before attempting to retransmit.

However, the delay caused by collisions and retransmitting is very small and does not normally affect the speed of trans -mission on the network.

The Ethernet protocol supports for bus, star, or tree topologies.

Data can be transmitted over wireless access points, twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps up to 1000 Mbps.

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FAST ETHERNET

It allow for an increased speed of transmission.

The Ethernet protocol has developed a new standard that

supports 100 Mbps. This is commonly called Fast Ethernet.

Fast Ethernet requires the use of different, more expensive

network concentrators/hubs and network interface cards.

Fast Ethernet requires category 5 twisted pair or fiber optic

cable is necessary. Fast Ethernet is becoming common in

LAN.

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GIGABIT ETHERNET

The most recent development in the Ethernet standard is a protocol that has a transmission speed of 1 Gbps.

Gigabit Ethernet is primarily used for backbones on a network at this time.

In the future, it will probably be used for workstation and server

It can be used with both fiber optic cabling and copper.

The 1000BaseTX, the copper cable used for Gigabit Ethernet.

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LOCALTALK

LOCALTALK is a network protocol that was developed by

Apple Computer, Inc. for Macintosh computers.

The method used by LOCALTALK is called CSMA/CA (Carrier

Sense Multiple Access with Collision Avoidance).

It is similar to CSMA/CD except that a computer signals its

intent to transmit before it actually does so.

LOCALTALK adapters and special twisted pair cable can be

used to connect a series of computers through the serial port.

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LOCALTALK

The Macintosh operating system allows the establishment of a peer-to-peer network without the need for additional software.

In the addition of the server version of AppleShare software, a client/server network can be established.

The LOCALTALK protocol support for linear bus, star, or tree topologies using twisted pair cable.

A primary disadvantage of LOCALTALK is speed. Its speed of transmission is only 230 Kbps.

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P R O T O C O L

TOKEN RING

The Token Ring protocol was developed by IBM in the mid-1980s. The access method used involves token passing.

In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring.

A single electronic token moves around the ring from one computer to the next.

P R O T O C O LTOKEN RING

If a computer does not have information to transmit, it simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token.

The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer.

The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable.

It can operate at transmission speeds of 4 Mbps or 16 Mbps. Due to the increasing popularity of Ethernet, the use of Token Ring in LAN environments has decreased.

F D D I - FIBER DISTRIBUTED DATA INTERFACE

Ω Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances.

Ω The access method used by FDDI involves token-passing. FDDI uses a dual ring physical topology.

Ω Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring.

Ω A major advantage of FDDI is speed. It operates over fiber optic cable at 100 Mbps.

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ATM - ATM - Asynchronous Transfer Mode

Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher.

ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets.

ATM supports a variety of media such as video, CD-quality audio, and imaging.

ATM supports a star topology, which can work with fiber optic as well as twisted pair cable.

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ATM - ATM - Asynchronous Transfer Mode

ATM is most often used to interconnect two or more local

area networks.

It is also frequently used by Internet Service Providers to

utilize high-speed access to the Internet for their clients.

ATM technology becomes more cost-effective, it will provide

another solution for constructing faster local area networks.

P R O T O C O L

PROTOCOLPROTOCOL CABLECABLE SPEEDSPEED TOPOLOGYTOPOLOGY

EthernetEthernet Twisted Pair, Twisted Pair, Coaxial, FiberCoaxial, Fiber 10 Mbps10 Mbps Linear Bus, Linear Bus,

Star, TreeStar, Tree

Fast Fast EthernetEthernet

Twisted Pair, Twisted Pair, Fiber OpticFiber Optic 100 Mbps100 Mbps StarStar

LocalTalkLocalTalk Twisted PairTwisted Pair 0.23 Mbps0.23 Mbps Linear Bus or Linear Bus or StarStar

Token Token RingRing Twisted PairTwisted Pair 4 Mbps – 4 Mbps –

16 Mbps16 MbpsStar-Wired Star-Wired

RingRing

FDDIFDDI FiberFiber 100 Mbps100 Mbps Dual ringDual ring

ATMATM Twisted Pair, Twisted Pair, Fiber OpticFiber Optic

155 155 MbpsMbps - -2488 Mbps2488 Mbps

Linear Bus, Linear Bus, Star, TreeStar, Tree

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NETBEUI

NetBEUI stands for NetBIOS Extended User Interface and can be used only in small networks.

It requires no address configuration and provides faster data transfer than TCP/IP.

Each Windows computer in a NetBEUI network is configured only with a computer and workgroup name.

NetBEUI’s cross-platform support is limited to Windows and other Microsoft OS.

NetBEUI is not routable and not robust in unstable networks.

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IPX, SPX

♦ IPX/SPX stands for internet work Packet Exchange /

Sequented Packet Exchange.

♦ It is designed specifically for use with the Novell NetWare

Operating System.

♦ It is routable and otherwise similar to TCP/IP, except that

it has limited cross-platform support and cannot be used on

the internet.

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R I P

The Routing Information Protocol (RIP) was one of the

most commonly used interior gateway protocol (IGP) routing

protocols on internal networks which helps routers dynamically

adapt to changes of network connections by communicating

information about which networks each router can reach and

how far away those networks are.

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P R O T O C O LFTP

The File Transfer Protocol (FTP) is a network protocol

used to transfer data from one computer to another through

a network, such as the Internet.

FTP is a file transfer protocol for exchanging and mani

-pulating files over any TCP-based computer network.

A FTP client may connect to a FTP server to manipulate

files on that server. FTP is a popular choice for exchanging

files independent of the operating systems involved.

HTTP

Hypertext Transfer Protocol (HTTP) is a communications protocol for the transfer of information on the intranet and the World Wide Web.

Its original purpose was to provide a way to publish and retrieve hypertext pages over the Internet.

HTTP is a request/response standard between a client and a server. A client is the end-user, the server is the web site. The client making an HTTP request - using a web browser, or other end-user tool is referred to as the user agent.

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TELNET

TELNET (TELecommunication NETwork) is a network protocol used on the Internet or local area network (LAN) connections. It was developed in 1969 beginning with RFC 15 and standardized as IETF STD 8, one of the first Internet standards.

The term telnet also refers to software which implements the client part of the protocol.

TELNET clients have been available on most Unix systems for many years and are available for virtually all platforms.

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P R O T O C O LS M T P

Simple Mail Transfer Protocol (SMTP) is the de facto standard for e-mail transmissions across the Internet. SMTP is defined in RFC 821 (STD 10) as amended by RFC 1123 (STD 3).

The protocol used today is also known as ESMTP and defined in RFC 2821.

It is very common for email software to use SMTP to send mail and POP3 to receive it, but SMTP can be used to receive mail.

P R O T O C O LS M T P

Simple Mail Transfer Protocol (SMTP) is the de facto standard for e-mail transmissions across the Internet. SMTP is defined in RFC 821 (STD 10) as amended by RFC 1123 (STD 3).

The protocol used today is also known as ESMTP and defined in RFC 2821.

It is very common for email software to use SMTP to send mail and POP3 to receive it, but SMTP can be used to receive mail.

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POP3POP3

The Post Office Protocol version 3 (POP3) is intended to

permit a workstation to dynamically access a mail drop on

a server host.

It is usually used to allow a workstation to retrieve mail that

the server is holding for it.

POP3 transmissions appear as data messages between

stations. The messages are either command or reply

messages.

P R O T O C O LDHCP

Dynamic Host Configuration Protocol (DHCP) is a

protocol used by networked devices (clients) to obtain

the parameters necessary for operation in an Internet

Protocol network.

This protocol reduces system administration workload,

allowing devices to be added to the network with little or

no manual configurations.

P R O T O C O LNTP

The Network Time Protocol (NTP) is a time synchronization system for computer clocks through the Internet network. It provides the mechanisms to synchronize time and coordi -nate time distribution in a large, diverse internet operating at rates from mundane to light wave.

It uses a returnable time design in which a distributed sub network of time servers, operating in a self-organizing, hierarchical master-slave configuration; synchronize logical clocks within the sub network and to national time standards via wire or radio.

P R O T O C O LPPP

Point-to-Point Protocol, or PPP, is a data link protocol commonly used to establish a direct connection between two nodes over serial cable, phone line, trunk line, cellular telephone, specialized radio links, or fiber optic links.

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