Data Elements
Hello and welcome to another blog post here at SkyNet-SH. In this post I will be taking you through the data elements, providing an explanation and illustrative diagram for each. The topics I will be covering are; Cyclic Redundancy Check (CRC), Encapsulation, Datagrams, Address and Sequencing.
Cyclic Redundancy Check (CRC)
Cyclic Redundancy Check which is often abbreviated to CRC is a technique that works with and alongside error detection and error correction. CRC is active whilst data is being transmitted across devices and is in place to detect errors and hopefully resolve them, which is in the form of error correction. CRC is used throughout wired LAN connections and this is a technique which is implemented via a polynomial; this is a series of formulae that involve the same number.
The process of CRC is that it will divide the data by a number and then produce a result and the answer will usually be very precise meaning it will not just be a simple integer, instead it will most likely be a decimal which means there will be a remainder. This remainder will then be repackaged in with the original data and be re-calculated in the receiver device. Once the receiver devices receives the data along with the remainder, it will test the value to see if it is correct, if it isn't the outcome will resolve in an error being detected and this usually means that there must of been some form of data corruption during transmission. Therefore, data correction is executed and attempts to resolve and re-calculate the data.
Encapsulation (Frames and Packets):
Encapsulation is a process that deals with large files which are being sent across a wired network; WAN or LAN, it will split the file into smaller individual parts to make it easier and quicker for data transmission. In encapsulation, a frame is the actual data which is being sent between two devices and a series of these are known as packets. Each packet includes the main data which is known as a payload and is a 'term used to describe the data being sent.' (BTEC Level 3 - K. Anderson, 2010)
Datagrams:
Datagrams are considered to be a less reliable counterpart in regards to packets, but both are seen to be sent in a similar manor. The main difference is packets are sent via TCP and IP, which ensures that the data being transferred arrives at its destination. Compared to a datagram which is sent via UDP and IP, which ensures that it is sent as high quality as possible, regardless of whether it reaches its destination successfully or not.
Address:
Addresses are an important variable throughout networking and they are essential for providing a valid file path for data which is being transferred. There are two types of address; physical address and logical address, a physical address can be coded onto a network device and an example of this would be a MAC address, which identifies network communication interfaces that have been assigned to it. MAC addresses are commonly associated with Ethernet and WI-FI connections; wired and wireless. The second type of network is known as a logical address that can be set-up by a network administrator or network server, and an example of this would be an IP (Internet Protocol) address, which is a unique string of numbers that act as an identity for the device on the Internet.
Sequencing
When a file is being transmitted to another device across the network, they are split into packets and datagrams and to ensure that they are reassembled correctly and in order, they are given a unique identification number which is known as a 'sequence number'. If this number wasn't assigned to each packet and/or datagram, files would become out of sync and the data would not make sense, resulting in an error.
SkyNet-SH
Thank you for reading through today's post. I hope you have found something useful and worth knowing. Please stay tuned for more information, here at SkyNet-SH
Reference:
Base Information - Anderson, K. Jarvis, A. Kaye, A. Lawson, J. McGill, R. Phillips, J. and Smith, A. . Information Technology Level 3 Book 1 BTEC National. Harlow: Pearson Education Limited.
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