Siposs Arnold Konrad

Computer Networks

Coordonator: Mr. Dr. Z. Pólkowski

Computer Network standards

Source: http://www.netguru.net/ntc/NTCC6.htm

• Standards play an important role in networking. Without standards, manufacturers of networking products have no common ground on which to build their systems. Interconnecting products from various vendors would be difficult, if not impossible.

• It is necessary to have standards because if each company had its own protocol standards there would be a lack of communication from different machines and would result in one company being hugely successful and the other running out of business due to lack of being able to communicate with other machines. So this is why its necessary to have network standards such as: Token ring, Arcnet, Ethernet and FDDI.

ARCnet

Source: http://site.the.cz/index.php?id=28

• ARCNET is designated as a high-speed local area network (LAN) well-suited for real-time control applications in both the industrial and commercial marketplaces. Its proven design, robust performance and the availability of low-cost silicon have made it the network of choice between embedded microcontrollers.

• Originally developed by Datapoint Corporation in the mid-70s and moved to silicon in 1982, ARCNET continues to find new applications well beyond its original intention as a network for an Attached Resource Computer (ARCNET). The ARCNET Resource Center (ARC) is a play on those original words.

Description

Source: http://www.alrcnet.com/

• To start off, ARCnet is not a standardized network. All information provided here is gathered through the years by different people and by just making mistakes, so if you have other experiences don't be surprised, but share them with us.

• This way we can all learn from it.• ARCnet (Attached Resource Computer NETwork) was

originally developed by Datapoint Corporation in 1968, way before OSI and the like. The original purpose was a harddisk interface, later it became popular as a local area network.

• All distaces are rough estametes. The actual calculation should be done like this: an active device provides 24 Volt output, and needs atleast 5 Volt on the receving pins.

How ARCnet works

Source: http://ckp.made-it.com/arcnet.html

• In September 1977, the world's first commercially available local area network was first put into service at Chase Manhattan Bank, New York, as a beta-site. 

• Short for Attached Resource Computer network, ARCnet was developed by Datapoint Corporation in San Antonio, Texas. It was defined as a group of nodes that communicates to one another over a geographically-limited area usually within one building or a campus of buildings. 

• It was the simplest, and least expensive type of local-area network. It used a token-ring architecture, supported data rates of 2.5 Mbps, and connected up to 255 computers. A special advantage of ARCnet is that it permitted various types of transmission media to be mixed on the same network: twisted-pair wire (Max. extension 150 meters), coaxial cable (650 m.) and fibre optic cable (2.000 m.) 

• Today, ARCnet is still alive in numerous companies all over the world and has more than seven million installed nodes.

ARCnet features

Source: http://www.old-computers.com/history/detail.asp?n=23&t=3

Token Ring

Source: http://www.pcmag.com/encyclopedia/term/52963/token-ring

A Token Ring network is a local area network (LAN) in which all computers

are connected in a ring or star topology and a bit or token-passing scheme

is used in order to prevent the collision of data between two computers that

want to send messages at the same time. The Token Ring protocol is the

second most widely-used protocol on local area networks after Ethernet.

The IBM Token Ring protocol led to a standard version, specified as IEEE

802.5. Both protocols are used and are very similar. The most common

local area network alternative to Ethernet is a network technology

developed by IBM, called token ring. Where Ethernet relies on the random

gaps between transmissions to regulate access to the medium, token ring

implements a strict, orderly access method. A token-ring network arranges

nodes in a logical ring, as shown below. The nodes forward frames in one

Direction around the ring, removing a frame when it has circled the ring

once.

Definition

Source: http://searchnetworking.techtarget.com/definition/Token-Ring

Unlike Ethernet, Token Ring uses a ring topology whereby the data is sent from one machine to the next and so on around the ring until it ends up back where it started. It also uses a token passing protocol which means that a machine can only use the network when it has control of the Token, this ensures that there are no collisions because only one machine can use the network at any given time. Token Ring networks are now very rare because the cost and flexibility of Ethernet came to dominate the marke. When the first Token Ring computer comes online, the network generates a token. The token is a predetermined formation of bits (a stream of data) that permits a computer to put data on the cables. The token travels around the ring polling each computer until one of the computers signals that it wants to transmit data and takes control of the token. A computer cannot transmit unless it has possession of the token; while the token is in use by a computer, no other computer can transmit data. After the computer captures the token, it sends a data frame out on the network.

How Token Ring works

Source: http://www.datacottage.com/nch/troperation.htm#.VRbaWi7AqOV

A Token Ring network is an implementation of IEEE standard 802.5. Their token-passing ring access method, more than their physical cable layout, distinguishes Token Ring networks from other networks. Architecture The architecture of a typical Token Ring network begins with a physical ring. However, in its IBM implementation, a star-wired ring, computers on the network are connected to a central hub. Figure 3.23 shows a logical ring and a physical star topology. The logical ring represents the token's path between computers. The actual physical ring of cable is in the hub. Users are part of a ring, but they connect to it through a hub. Monitoring the System The first computer to come online is assigned by the Token Ring system to monitor network activity. The monitoring computer makes sure that frames are being delivered and received correctly. It does this by checking for frames that have circulated the ring more than once and ensuring that only one token is on the network at a time.

Token Ring features

Source: http://www.techopedia.com/definition/26095/token-ring-network

Ethernet

Source: http://hackd.org/sniffers-detailed-faqs/

INFORMATION

. Ethernet-is a family of computer networking technologies for local area networks (LANs) and metropolitan area networks (MANs). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3, and has since been refined to support higher bit rates and longer link distances. Over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI, and ARCNET. The primary alternative for contemporary LANs is not a wired standard, but instead a wireless LAN standardized as IEEE 802.11 and also known as Wi-Fi.

Source: http://en.wikipedia.org/wiki/Ethernet

• The term 'Ethernet' refers specifically to a set of standards for connecting computers in order they can share information over a common wire or network. Strictly speaking, ethernet systems should comply to the International Standard ISO/IEC 8802-3 or IEEE 802.3.

• As in all systems, there are reasons to use an ethernet network, but also difficulties that must be overcome. The main advantages of ethernet are:

• The ability to carry several hundred times more information on a single cable than would be carried on a typical serial cable. Whereas DMX512 operates at 250kb/s, Ethernet operates at 100 Mb/s - 400 times faster;

• The ability to connect multiple devices in a single network, regardless of the information interchange relationship between the devices. Ethernet allows all devices in the network to communicate;

• A reduction in the amount of cable required. Economic factors will drive the demand for this technology;

GENERAL INFORMATION

Source: http://www.webopedia.com/TERM/E/Ethernet.html

• The ability to add devices to the network at any time, giving a more flexible installation;

• Required components are readily available and have a relative low cost.

• Despite these factors, there are also disadvantages associated with ethernet systems:

• Maximum cable length between two devices is limited to 100metres, compared with 250metres for DMX512 systems. In larger installations, where very long cable runs are required, it is necessary to utilise fibre-optic cabling;

• RJ45 connectors used for ethernet networks are not suitable for heavy-duty use in industrial situations;

GENERAL INFORMATION (PART 2)

Source: http://www.webopedia.com/TERM/E/Ethernet.html

FDDI

Fiber Distributed Data InterfaceStandard specification

Introduction

Fiber Distributed Data Interface (FDDI) is a standard for data transmission in a local area network. It uses optical fiber as its standard underlying physical medium, although it was also later specified to use copper cable, in which case it may be called CDDI (Copper Distributed Data Interface), standardized as TP-PMD (Twisted-Pair Physical Medium-Dependent), also referred to as TP-DDI (Twisted-Pair Distributed Data Interface).

Source: http://www.webopedia.com/TERM/F/FDDI.html

• FDDI stands for Fiber Distributed Data Interface. The FDDI standard is ANSI X3T9.5 . The FDDI topology is ring with two counter rotating rings for reliability with no hubs. Cable type is fiber-optic. Connectors are specialized. The media access method is token passing. Multiple tokens may be used by the system. The maximum length is 100 kilometers. The maximum number of nodes on the network is 500. Speed is 100 Mbps. FDDI is normally used as a backbone to link other networks. A typical FDDI network can include servers, concentrators, and links to other networks. CDDI is a copper version of FDDI which uses category 5 cable. Obviously the distance is more limited than FDDI.

• Devices called concentrators provide functions similar to hubs. Most concentrators use dual attachment station network cards but single attachment concentrators may be used to attach more workstations to the network.

Specification part 1

Source: http://www.comptechdoc.org/independent/networking/cert/netfddi.html

Specification part 2

Source: http://www.cisco.com/c/en/us/td/docs/internetworking/technology/handbook/ito_doc/FDDI.html#wp1020549

Therefore a break in the cable will result in the secondary ring being used. There are two network cards which are: 1.Dual attachment stations (DAS) used for servers and concentrators are attached to both rings and a router or switch can link an FDDI network to a local area network (LAN). Normally FDDI is used to link LANs together since it covers long distances. Characteristics Summary:•Topology - Double ring. •Cable - Fiber. •Speed - 100Mbps. •Maximum segment length - 2000 meters. •Media access - Token passing. •Maximum nodes on the network - 500. TroubleshootingPlastic fiber is only useful to 50 meters. Multimode glass is good to 2 kilometers. A tool called an Optical time domain reflectometer (OTDR) may be used to debug this network.

LAN Network’s

• When talking about LAN Networks, we need to know how they work .• That is why we can use simulation programs to virtual make connections between more computers and hubs or switches.

Network devices

• For a network to work, we also need to have network devices, that is why i will show you some devices i configurated during classes.• When you configure a router you first need to change username and password which you will use to login to your router:

Network devices

• After you configure account you need to configure the wireless connection and IP adress.

Network devices

• By doing this you only need to configure security and your router is ready to work and transmit wireless internet to all the computer/laptops in the room .

Network devices

• Other devices that i tested sucesfully are:

• Site com wire less micro USB Adapter 150N, which can be tested by downloading and installing it’s software, than read the microUSB from my PC after restarting the computer. Downloading and installing was easy because the package came with the CD that had the instruction manual and the software as well. I also checked on the security using the password and mac address.

Source: http://www.wireless-driver.com/sitecom-wl349-windows-drivers-utility/

Network devices

• The last device i have checked was an Sitecom 300N wireless Gigabit modem router, which was simple to configure you just need to reset the device, enter the adress and log in to the device and follow the wizard setup which whill guide you through the configuration, after this is completed the device should work properly.

Source: http://www.bol.com/nl/p/sitecom-300n-wireless-gigabit-modem-router/1003004012112299/

References

• http://site.the.cz/index.php?id=28• http://3w.dokisoft.com/why-computer-networks-have-interruptions/• http://www.pcmag.com/encyclopedia/term/52963/token-ring• http://hackd.org/sniffers-detailed-faqs/• http://www.freepik.com/free-photo/ethernet-cables-close-up_605844.htm• http://www.webclasses.net/3comu/intro/units/unit05/sec03f.html