Cisco Networking Assessment Essay Example | Topics and Well Written Essays - 1500 words

Cisco Networking Assessment - Essay Example Error correction also includes the additional ability to reconstruct the original message, with error-free data. Two basic methods have been designed to handle the error correcting system. These are called the Automatic repeat-request (ARQ), and the Forward Error Correction (FEC). The ARQ sends that data with an error detection code, which the receiver user to check for errors. In the FEC method the transmitter includes an error-correcting code (ECC) and sends the coded message. The receiver never sends any data to the transmitter, it just decodes what it thinks is the most "likely" data. The Network Layer deals with errors via a variety of means (Wikipedea, 2008). These are to ensure the QOS is maintained. These can be items such as the Parity check, which means that if any bits are corrupted in the message, they are replaced to the expected format. A checksum, which involves an algorithm to check the validity of the data, Hash functions, which perform a similar function and repetition schemes. The full list of methods is stated here: The Transport Layer uses 2 two way error correction protocol, which involves a discussion between the sender and the receiver. This is where the receiver informs the transmitter to resend a message when an error occurs. ... Repetition schemes Parity schemes Checksum Cyclic redundancy checks Hamming distance based checks Hash function Cryptographic message digest Horizontal and vertical redundancy check Polarity schemes Transport Layer: The Transport Layer uses 2 two way error correction protocol, which involves a discussion between the sender and the receiver. This is where the receiver informs the transmitter to resend a message when an error occurs. The two basic types for each packet transferred are called a NACK (Not Acknowledged), when a failure occurs and an ACK (Acknowledged) when a packet has been successfully received. The way it does this is to check the header/footers of packets to see if it is in the format expected. This is usually achieved by CRC (Cyclic Redundancy Check) checksums which are calculated based on the data transmitted. Summary: Basically, the Network Layer function is to check the validity of the data at a lower level than the Transport Layer, and communicates the problem up the hierarchy. The Transport Layer in turn, informs the transmitter to resend the erroneous data. The Transport layer has other functions, such as allowing a mechanism where the receiver informs the transmitter what to send next and what is expected. Question 2 (5 marks) What are the different types of collisions that can occur on an Ethernet network Briefly explain each. There are the types of collision where two packets are sent over the network at the same time, and this is handled by the CSMA/CD (Carrier Sense Multiple Access / Collision Detect) protocol and a 'Collision Domain'. A Collision Domain happens when two devices on the network transmit at the same time (The TCP/IP Guide, 2005). An Ethernet network can be composed of a single or a multiple

Analysis of Anti-Semitism and Racism in Gentleman's Agreement(1947) Essay

Analysis of Anti-Semitism and Racism in Gentleman's Agreement(1947) movie - Essay Example Because of its unique subject, clarity of expression and excellent cinematography, this movie won three Oscar awards, one for being the Best movie in 1947, second for having the Best Director, and the third award went to Celeste Holm for being the Best Supporting Actress. Jews have for longed, suffered in America. Jews had been subjected to anti-Semitism in America. In Fortune, an article was published in 1936 which said that Jews were subjected to attacks because of â€Å"inviting prejudice because of their notorious tendency to agglomerate not just in cities but in self-constituted communities within cities†¦Ã¢â‚¬  (Blum 173). Such articles flared up the stereotypical images of Jews in the public. Jews were treated were badly. There used to be overt expression of racial discrimination by other communities against the Jews. There was discrimination against Jews in the fields of education, accommodation, immigration and employment. Phil Green who is one of the leading characte rs in the movie Gentlemas’s Agreement, plays the role of a news reporter that experiences racial discrimination. Phil is tasked to express his views on anti-Semitism. In order to achieve that, Phil presents himself before the public as a Jew contrary to the fact that he is a Gentile.