Ethernet system Essay Example for Free

Ethernet body EssayRobert Metcalfe with his colleagues at the Xerox Palo alto query Center (PARC) substantial the experimental Ethernet frame. According to OReilly and associates (2000) the main purpose of developing the Ethernet schema is to join a personal workstation with graphical user interface c each(prenominal)ed Xerox Alto. The experimental system was used in prep are to connect Altos and also printers and servers. The systems interfaces signal clock was patterned in the Altos system clock. This essenceed to 2. 94 Mbps. data transmission rate on the experimental Ethernet. Ethernet was origin each(prenominal) in ally know as Alto Aloha Ne cardinalrk. Alto Aloha Network was changed its name to Ethernet by Metcalfe to indicate that the system not precisely support Altos but also otherwise computers. And Metcalfe also present out that the Ethernet has progressed way beyond the Aloha system. He chose the name ether as to describe the congenital feature of the sy stem which is the natural medium carries bits to all stations the same way as the metal(prenominal) ether was once believe to proliferate There atomic number 18 two ways which stub be used to allocate the capacity of transmission media baseband and broadband transmissions.Baseband transmission allocates the entire capacity of the medium to sensation conversation conduct. It uses distinct values by measuring the voltage in wire which only carried virtuoso signal at a time. In broadband transmission, the system allows two or much discourse channels to divide the bandwidth of the communication medium. The system uses the technique of dividing the bandwidth into frequency bands which is called frequency division multiplexing (FDM) which works only with analog signals. There is also another technique called time-division multiplexing (TDM) that supports digital signals.Figure 1, show the difference surrounded by baseband and broadband transmission mode of operation Figure 1. D ifference in the mode of operation amid baseband and broadband Broadband transmission is used in the net hosting companies. This is because of the higher speeds of the broadband. With the use of broadband, people lot enjoy the full range of internet services like downloading videos, music, watching movies and plying online games. Transceivers have dissimilar speeds which are measured in MHz and also specified in wavelengths.The larger the value of the fiber nerve centre of the transceivers, measured in microns, there will be more bandwidth possible but also the aloofness will be shorter. The 1000 Base-LX is the long wavelength with a signaling speed of 1. 25100 ppm GBd. This transceiver bottom of the inning use both 62. 5 and 50 micron multimode fiber and it also uses single-mode fiber optic cables with outdistances of 440m, 550m and 5 km. Another trans put one overr is the 100 Base-TX which uses 4B5B binary encoding to encode 100 Mbps data stream in a signal of 125 MHz. One twin is used for transmitting data while the other pair is used for receiving the data.Given this, one user can setup a system for full duplex communication given that there are only interfaces in the same collision domain. It is either the two computers are directly connected to each other by crossover cable or a computer directly connected to a switch. Full duplex communication result to doubling the potential difference throughput but not often reached more than the modest improvement. Based on Sheldon and Big Sur multimedia system (2001), link aggregation is the care for of connecting together two or more data channels in order to become a single channel which appears as a single, higher-bandwidth logical link.Also this aggregative links can provide redundancy and fault tolerance if the links follow different physical path. By linking the digital lines, the link aggregation improves the admission charge to public meshs. The aggregation is also use in enterprise network to build multigigabit backbone links. It also allows the networks backbone speed to get down increasingly when the demands on the network increases without replacing everything and buy new and expensive hardware.Carrier Sense quadruple Access with Collision Avoidance (CSMA/CA) communications protocol was intend for local area network (LAN) environments where in all the leaf nodes are positioned few hundred feet from each other. The importance of the protocol is to listen up each node to the channels in a short period of time before it transmits. The main presumptuousness of the protocol is that each node should be able to hear the transmission from every other station. But this assumption is violated in approach shot network and this resulted to several problems. One of the skilful problems encountered is the hidden transmitter problem.This occurs when the CSMA/CA cannot function properly due to a radio node cannot hear one or more of the other nodes. And when this happen, m ultiple nodes attempt to transmit their data simultaneously over the shared data gum olibanum resulting to interference with each other. To address the hidden transmitter problem, the 802. 11 hackneyed uses the protocol request to carry/clear to send (RTS/CTS). Before transmitting each packet, each node transmit an RTS packet to other nodes to warn them that it is about to transmit data and after each transmission, it broadcasts CTS packet.This member is time and bandwidth consuming process and it is required for each and every transmission by each and every wireless node. But this process sill does not address the hidden transmitter problem fully because RTS/CTS packets are subjected to repeated collisions. In about applications, the wireless warning 802. 11b operating at 2. 4 ghz is ample enough. This wireless remain firmard is the largely widely accepted standard among the three wireless standards and also the price of the equipment is the cheapest because of the rising d emand for the 802.11g. Its distance will rely mostly on the communicating devices whether it have line of site or not. And with less obstacles among the transmitting and receiving devices, there will be discover wireless connection and therefore much better web surfing. The 802. 11b wireless standard is good enough if development wireless route or access point only for internet usage because the connection to internet via broadband modem operates about 2mbps which is very fast. The 802. 11b broadcast data at the rate of 11mbps which is sufficient for internet usage.This device saves money on equipment and gives great web surfing services. Another wireless standard being used is the 802. 11g standard. It is replacing the widely accepted standard which is the 802. 11b because both operate on the same frequency and the price drastically goes down on products. This standard is much very similar to 802. 11b because it also usually needs a line of site to gain optical performance. Bo th standards, 802. 11b and 802. 11g operate at the same frequency range of 2. 4ghz and are inter-operable with each other. whole the devices of 802. 11g can communicate with 802.11 devices and the main advantage of the 802. 11g devices is that when transferring files in the midst ofs computers or networks, it is usually at a greater speed. It is recommended to use 802. 11g when using wireless connection to transfer files (data files, voice, music, and videos) around the home and side. 802. 11g standard also allows manufacturers to developed devices which work at speed of up to 108mbps because it recommended when transferring large data or audio files within LAN. Wi-Fi defend Access (WPA) is a security technology that is used in wireless network.This was created by an industry mountain group called the Wi-Fi Alliance which owns the trademark for the name Wi-Fi and certifies products that bear the name. WPA was created in order to response on the serious weaknesses of the previou s system, the Wired Equivalent Privacy (WEP) and also to improve the earmark and graveion features of the WEP. It implements majority of the IEEE 802. 11i and intended to take place the place of WEP. It was designed in order to work with all wireless network interface cards but not with first generation wireless access point.Temporal recognise Integrity Protocol (TKIP) is one of the key technologies behind WPA which deals with the encryption weaknesses of the WEP. Also the WAP have built-in earmark which is a key component. The WAP uses the RC4 stream cipher which has a 128-bit key and a 49-bit initialization vector (IV). With the junto of the TKIP and the RC4 stream cipher this solves the problem of key recovery attacks which was found in WEP. In addition, the WPA provides much improve payload integrity.WPA uses a more secured message authentication code (MAC) but also termed as MIC which stand for message integrity code which is an algorithm Michael. MIC includes a frame cou nter preventing replay attacks. With the features of the WPA like having change magnitude size of the keys and IVs, reduced number of packets sent with related keys and adding up of a secured message substantiation system, it is far more difficult to break in within the system. There is one variation in WPA which is called the WPA pre shared key (WPA-PSK), which is also known as personal mode.This was designed for home and small office usage and networks which cant afford the cost and complexity of the 802. 1X authentication server. To access the network, the user must(prenominal) enter a pass phrase, with 8 to 63 printable ASCII characters or 64 hexadecimal digits. This can be stored in the users computer with discretion under most operating system in order to avoid re-entry and must remain in the Wi-Fi access point. Protected Extensible hallmark Protocol (PEAP) securely transmits authentication randomness which includes password, over wired and wireless network.It is also an 802. 1x authentication suit for wireless LANs. The PEAP is created by the Cisco Systems, Microsoft and RSA Security which is base on the Internet Draft submitted to the IETF. (Cisco Systems, 2007) The system uses only server side public key certificates which authenticate clients by creating encrypted SSL/TLS tunnel in between client and authentic server. This protects from casual inspection the resulting turn of authentication. According to the Cisco Systems Inc. , the following are crucial benefits of the PEAP web security system It relies on the Transport Layer Security (TLS) which allow non-encrypted authentication types (EAP-Generic particular Card and One Time Password (OTP)) support It uses the server-side Public-Key Infrastructure (PKI) ground digital certification authentication It allows for the authentication to an extended suite of directories which include Lightweight Directory Access Protocol (LDAP), Novell NDS and OTPA databases It uses the TLS in order to enc rypt all the user-sensitive authentication information It supports the password change at expiration It does not display the logon username in the EAP identity response The system is not susceptible to dictionary attacks It offer dynamic privacy auspices while using in combination with Temporal Key Integrity Protocol (TKIP) or the mature Encryption Standard (AES) Also the PEAP have enterprise benefit. Based on the Cisco System Inc. , PEAP is based upon the server-side EAP-TLS. This means that organization can avoid the issue associated in the installing of digital certificates on every client machine which is required by the EAP-TLS.This provides the enterprise to choose what method of client authentication depending on their needs. PEAP authentication work in two phases ? In phase 1, performing the server-side TLS authentication will result to creation of an encrypted tunnel and will achieve server-side authentication. One the process is done the data are encrypted with all th e user-sensitive information ? For phase 2 according to the Cisco System Inc. , the client is authenticated by using methods like the EAP-GTC and the Microsoft Challenge Authentication Protocol (MS-CHAP)Public switched tele name network (PSTN) is referred as the public communication providing local, extended and long distance call telephony service. It is composed of foretell exchanges arranged in order to have nationwide telephone communication system. The system is open for those who can afford the service. Packets, pieces of the callers conversation are switched and then sent simultaneously to many connections to reach a receiver in the other end. All the phones in PSTN are connected in a way that any phone can call to any other phone due to all the local phone systems are connected to each other.Mitchell (2007) cited that PSTN provides the traditional Plain Old Telephone Service (POTS) to establishments and residences and also some move of the PSTN are being utilized for DSL, VoIP and other internet-based network. In much relation to internet, this provides much of the internets long-distance infrastructure. Internet service providers (ISP) pay the long distance provider for the access to their infrastructure and they share the circuits among users in the process called packet switching.PSTN network link supports 64 kbps and in residences the PSTN phone lines carrying the bandwidth is made up of copper cable. Dial-up modems utilize 56kbps of the bandwidth when they are connected to a phone line. Also the PSTN utilizes the SS7 signaling protocol. SS7 signaling protocol support the exchange of special-purpose messages on public telephone networks. SS7 messages pass over separate channel different from the channel used for voice communication and it is referred as out of band signaling. Wireless local enlaceing is sometimes called radio in the loop (RITL) or fixed radio access (FRA).It is a system that connects users and subscribers to the public switche d telephone network (PSTN) by the use of radio signals as substitute for copper for all part of the connection between subscriber and the switch. This includes cordless access systems propriety fixed radio access and fixed cellular systems. One of the advantages of the wireless local loop is that it can be deployed in dependable weeks or months in comparison with copper wire systems which took months and years for the deployments. The instillation of the wireless local loop considerately has much lower construction cost than laying copper lines.The maintenance and operations of the wireless local loop are that easy and the average maintenance time per subscriber is shorter by 3 to 4 times. Signaling is the exchange between information which concerns about the establishment and in the control of a connection and the management of the network. There are many types of signaling In-band signaling pertains to the exchange of signaling information within the same channel of the telephon e call Out-of-band signaling is telecommunication signaling meaning exchange of information to control telephone call.It is done over a channel and it separates from channels which is use for telephone call. This signaling is used by Signaling system 7, the signaling standard controlling the worlds phone calls Line signaling is much concerned in transmitting information on the declare of line or channel Register signaling is focused on the transmittance of information in the calling/ called telephone number Channels-associated signaling utilizes signaling channels dedicating to a specific bearer channel Common-channels signaling, utilizes signaling channels which transmit signaling information to multiple bearer channels. Compelled signaling pertains to the need of the receive signal to be fully acknowledged before the next signal is sent. Subscriber signaling pertains to the telephone and the telephone exchanges Trunk signaling pertains to the exchange.References Buis, Paul . (1996, family line). Common 100 Mbps Hardware Variations. Ethernet TechnologyUnderlying Technologies. (Chapter 4). Retrieved September 16,2007 from http//www. cs. bsu. edu/homepages/peb/cs637/ethernet/100mbps. htm reckoner Hope. (2007). Ethernet. Retrieved September 16,2007 from http//www. computerhope. com/jargon/e/ethernet. htm ETSTechNEWS.What is the difference between 802. 11g and 802. 11b? Retrieved September 17, 2007 from http//web. monroecc. edu/ETSTechNEWS/80211g Fleishman, Glenn. (2003, November 4). Weakness in Passphrase Choice in WPA Interface. Retrieved September 17,2007 from http//wifinetnews. com/archives/002452. html GNS Wireless LLC. 802. 11a vs. 802. 11b vs. 802. 11g. 2007. Retrieved September 16, 2007 from the http//www. gnswireless. com/AvsBvsG. htm Laverty, Denis. WPA vs. WEP How your Choice Affects your Wireless Network Security. Retrieved September 16,2007 from http//www. openxtra. co. uk/articles/wpa-vs-wep. php McLauren, Bruce. (1998).Cabling Options. How Gigabit Ethernet works. Retrieved September 15,2007 from http//misnt. indstate. edu/coutinho/ge/WORKS. HTM Mitchell, Bradley. Wireless/networking WPA Wi-Fi Protected Access. Retrieved September 16,2007 from http//searchnetworking. techtarget. com/sDefinition/0,,sid7_gci214316,00. html Ou, George. (2005,June 2). Understanding the updated WPA and WPA2 standards. Message posted to http//blogs. zdnet. com/Ou/index. php? p=67 Pidgeon,Nick. Introduction to how Ethernet Works. The Ethernet. Retrieved September 16,2007 from http//computer. howstuffworks. com/ethernet. Sheldon, Tom.Link Aggregation. The Encyclopedia of Networking and Telecommunications. Retrieve September 16,2007 from http//www. linktionary. com/l/link_aggregation. html Spurgeon, Charles E.. (2000). Why is it called Ethernet?. Ethernet The classical Guide. Retrieved September 16,2007 from http//www. ethermanage. com/ethernet/ethername. html ICT Global. What is Ethernet?. Ethernet FAQ. Retrieved September 16,2007from http// www. ictglobal. com/ICT010/faq1. html Networking Essentials. Band Usage (Baseband or Broadband). Retrieved September 17,2007 from http//www. measureup. com/testobjects/MS_NetEss/5a67289. htm