#contents

//** Week 1 Introduction
//
//Hello everyone, my name is Yuji Shimojo and I'm 27. I am from Okinawa, Japan and live there now. I'm in charge of presales of cloud systems integration and application development at an IT company based in Okinawa. Actually, I used to study Information Engineering at University of the Ryukyus in Okinawa, but I dropped out of the college 5 years ago. While in the college, I had lived in San Jose, California for 6 months for an internship. I'm currently majoring in Computer Science with a minor in Business Administration. I took CMIS242, CMSC335, CMSC350, CMSC325, CMSC330, CMSC412, CMIS330, and CMIS320 as part of my major in the past. I'm aiming to enhance my sales engineer career through studying in UMUC.

** Week 1 Discussion [#v549f4bc]

- Question

''How do you connect?''

I connect to the internet via a DSL connection. Actually, I have a wireless connection to a linksys router that is connected to Verizon DSL via a Telephone Twisted Pair connection to a standard telephone jack.

Please answer the following questions:
-- How are you connecting to the internet?
-- Include in the description the media or wire.
-- Include in the description how quick the connection is and how reliable.

''Protocol Layers''

Think about what is happening as you are accessing this class. While you are browsing you are using a Web Browser (application layer) that is talking to the TCP (transport) layer that is talking to the IP (Network) layer that is talking to the link layer. Notice I did not say what the link layer is. I do not know. Look back at others responses to this activity and read how others are connecting.

Please answer the following questions:
-- How many different link layers do you think the people in the class are using?
-- Since we are all interacting did you notice the different layers?
-- If not why not?

- Answer

''How do you connect?''

-- How are you connecting to the internet?

At my home, I connect to the internet via a FTTH connection.

-- Include in the description the media or wire.

In addition to an Ethernet connection, I also have a wireless connection to a Buffalo router that is connected to KDDI FTTH with a max speed of 1Gbps via a Twisted Pair connection to an ONU device provided by KDDI, which is the second largest communication carrier in Japan.

In my room on the second floor, since the wireless connection is slow, I extend internet access by using Panasonic power line Ethernet adopters that are plugged into AC outlets. One adopter is connected to the Buffalo router, and another one is connected to my computer with an Ethernet cable.

-- Include in the description how quick the connection is and how reliable.

Actually, the power line connection becomes sometimes unstable. Although I do not know the exact reason, I assume electric currents perhaps interfere with the network communication.

Protocol Layers
''Protocol Layers''

-- How many different link layers do you think the people in the class are using?

After I saw classmates' posts, each classmate seems to have one or more link layers such as Ethernet and Wi-Fi.

-- Since we are all interacting did you notice the different layers? If not why not?

No, I did not. Because the internet uses TCP/IP that is a globally standardized communication method, and we are all interacting in this class via the World Wide Web which uses HTTP or HTTPS protocols, higher layers such as application and transport layers do not identify lower layers such as network and link layers. In other words, all we need to do is to open a Web browser and to know the URL to access to this Web site.

** Week 1 Homework 1 [#uc115f2f]

- Question

1) What layers in the protocol stack (both logically and physically) does the HTTP protocol talk to?

2) What might a protocol frame from a Web Browser session look like as it goes out of a network port? Assume the link layer
is ethernet. You do not need to describe the fields inside a particular header except to say it is a particular protocol header (ie TCP header).

3) I can change a link layer protocol and the application layer protocol does not need to know or be made aware of the change. Explain why?

- Answer
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