Data elements

Data elements

In this blog I will be explaining the different data elements. The ones I will be explaining are cyclic redundancy check, encapsulation, datagrams, addresses and sequencing.

Cyclic redundancy check

Cyclic redundancy checking (CRC) is a method for checking errors in packets of data that has been sent via communications. This happens by using a technique called a polynomial. This attaches a code to check if the data is correct. The device that is receiving has the same code as the data being sent so it can check if it is correct or not. If it is not correct, the data will be requested again and it will be sent. This will happen until the data gets there correctly.

Encapsulation

Encapsulation uses frames and packets for sending information. A frame is the data sent from device to device. Larger items such as a video will be split up into smaller frames to be sent. Packets are a collection of frames and they are normally sent by protocols such as an IP (Internet Protocol). An example of a frame would be an Ethernet frame.

Datagrams

A datagram is very similar to a packet. Datagrams are used for sending information and they are used in protocols such as the Internet Protocol. The difference between datagrams and packets is that datagrams use UDP (User Datagram Protocol). This makes it less reliable because you do not get a response if it failed or not.

Addresses

Network addresses is a unique identifier for a computer on a network. There are many different types of network addresses. An example of one these would be an IP address or a MAC (Media Access Control).

Sequencing

Sequencing is when data packets are labelled. This allows them to be sent down separate paths in the network and still get to the device. When all of the packets are at the end they can be re sequenced. As all of the packets had been labelled they could be easily put back together and there would be no problems.

References

Anderson, K. Atkinson-Beaumont, D.Kaye, A. Lawson, J. McGill, R. Phillips, J and Richardson, D., 2011. Information Technology Level 3 Book 2 BTEC National. Harlow: Pearson Education Limited.

TechTarget (2015) Cyclic redundancy checking [Online] Available at: http://searchnetworking.techtarget.com/definition/cyclic-redundancy-checking [Accessed on: 26/01/15]

TechTarget (2015) Datagram [Online] Available at: http://searchnetworking.techtarget.com/definition/datagram [Accessed on: 26/01/15]