#Week 2. 2 technologies in the history of the Internet that paves the way to today's reality

 

For the second week task, I will talk about 2 technologies in the history of the Internet such as Aloha that has become obsolete and Ethernet technology that is currently used even though the media used has evolved.

First of all, I think it is important to remark that the World Wide Web didn’t come up from nothing but it was the result of multiple steps forward, out of the necessity, to search for solutions to unsolved problems. 

Therefore, for instance the ARPANET group wanted to provide remote access to their main computer  system and they were using telephone lines to do so.


  By other hand, The system known as Aloha and created by Norman Abramson wanted to do it through shared radio network to overcome the terrain barriers and being able to communicate between the different islands in the Hawaii Archipelago. I took this example as a technology that is no longer used even though it inspired the new wireless technologies that are valid today. The main idea is that terminals can transmit their data regardless of the activity of other terminals. If a message is successfully received, the base station sends an acknowledgement back over the feedback channel. If the acknowledgement is not received, then the message is retransmitted after waiting a random time. With many users involved, the number of collisions will also dramatically increase, which will require retransmission and therefore decreasing the throughput and even collapsing the media.
As an improvement to the original Aloha, the protocol "Slotted ALOHA" was created and increased the maximum throughput by introducing discrete timeslots. A station can only start a transmission at the beginning of a timeslot. 



Unlike the ARPANET where each node could only talk directly to a node at the other end of a wire or satellite circuit, the fact that it used a shared media, generated a considerable interest and several projects were initiated thanks to the idea. Among those I can highlight the Ethernet, that is still operative. Unlike the Aloha system, in which transmitters could not receive any signals, Ethernet stations could detect that collisions had occurred, stop transmitting immediately, and retry a short time later (at random). Ethernet was at first used to connect around 100 computers in Palo Alto (EEUU) and with the help of David Clark’s group at MIT, built an efficient TCP implementation which led to the proliferation of PCs connected by LANs and increasing the size of Internet.

Ethernet is one of two LAN technologies used today, with the other being wireless LANs (WLANs). Ethernet uses wired communications, including twisted pair, fiber-optic links, and coaxial cables.

Ethernet operates in the data link layer and the physical layer. It is a family of networking technologies defined in the IEEE 802.2 and 802.3 standards.

Find here below the sources used for this entry:

  1. https://www.nap.edu/read/6323/chapter/9#175
  2. https://www.clear.rice.edu/comp551/papers/Abramson-Aloha.pdf
  3. https://www.researchgate.net/figure/Example-of-SIC-enabled-slotted-ALOHA-Packet-2-is-received-in-singleton-slot-3-enabling_fig3_309551186
  4. http://www.wirelesscommunication.nl/reference/chaptr06/aloha/aloha.htm
  5. Networking Academy CCNAv7 curriculum, Introduction to Networks (ITN)




Comments

Post a Comment

Popular posts from this blog

# Week 9 Two opposite examples of ergonomics/usability/HCI in the smartphone market

This week I will talk about 1 design failure and 1 design that succeeded in the technology field particularly cell phones.  First, as a failure I will talk about the GALAXY NOTE 7. It was released in 2016 and was meant to be a revolution and a direct competitor of iPhone. It had several and gorgeous innovations such as a curved display, a long battery life, and a camera that could rival the iPhone.  For example talking about the screen, It had a 5.7-inch AMOLED display with curved edges that wrap to the side of the phone, and a slightly rounded back, giving it a surprisingly good feel. Some other interesting features were to be water resistant and incorporate iris scanning too. Talking about HCI The icons were softer and more rounded, and a lot of the settings seemed easier to access, and so on.  It is proven that they put a lot of effort in the phone and the expectations of success were at the highest. It was actually for many reviewers the best phone Samsung ever made. ...
Read more

#Week 5. The Case for Copyright Reform Task

For this week I will give my opinion about the book  The Case for Copyright Reform . The book and particularly chapter 2 is trying to convince readers that the copyright as it’s been conceived, it is not good for society because if it is going to be applied effectively, it will collide with fundamental rights and they are advocating for a modification. When the author say that this copyright law is endangering fundamental rights, it means that if you really want to avoid people sharing digital files, you need to sniff the communication between them and see what kind of information they are exchanging which of course lead you to know everything else if you want to.   That is a difficult debate. If you think that you are harming an author you admire,  most of the people will be in favour of a tough copyright law. By other side, If you think that this law is attempting against your fundamental rights and that it is not protecting the author but the industry and all the ...
Read more