Home / Summaries / Computer Networking: A Top-down Approach / application-tcp-ssl

Application layer

9 important questions on Application layer

List five nonproprietary Internet applications and the application-layer protocols they use.

Web: HTTP, File transfer: FTP, Remote login: Telnet, Network News: NNTP, Email: SMTP

What is the difference between network architecture and application architecture?

Network architecture refers to the organization of the communication process into layers (e.g., the five-layer Internet architecture). Application architecture, on the other hand, is designed by an application developer and dictates the broad structure of the application (e.g., client-server or P2P).

For a communication session between a pair of processes, which process is the client and which is the server?

No. In a P2P file-sharing application, the peer that is receiving a file is typically the client and the peer that is sending the file is typically the server.
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart
Testimonial person
Sophia
Law student
Quotes

For my 1st exam I got a C. Then, I started looking for ways to learn better and I came across Study Smart. Since then I have scored a A+, A, A- and another A. I highly recommend it to everyone who wants to hear it. I am so happy with it!!

Testimonial person
John
Economics Student
Quotes

I was struggling to finish all my first-year subjects for 3 years. Then I discovered Study Smart, which helped me to finish all of them within 3 months.

Testimonial person
Sara
Public Administration Student
Quotes

Because of StudySmart, things are going well in many ways. Before, I always had study stress and no time for anything. Now I feel calm and confident (because of the program). I used to score a B, now I usually score an A or A+.

Testimonial person
Mary
Business Student
Quotes

Hey Chris, I really want to thank you very much for developing the platform, I usually got around C for my exams, now I scored an A+, an A and a A- !!

Testimonial person
Melanie
Psychology Student
Quotes

Since using Study Smart, my average has increased significantly. I even completed a statistics course with a A+ while I'm bad at statistics. I took on extra courses this year, because of Study Smart. Thanks so much!

Testimonial person
Jane
Nursing Studies
Quotes

Ever since I started studying with StudySmart I passed all my exams !!! No more re-sits!! At first, I was happy with a pass and now I only get good grades. Many thanks!

Testimonial person
Rose
Political Science Student
Quotes

I aced all the courses I studied with Study Smart. For law, I first scored a D, and now an A! I’m 100% sure that I’ll pass all the courses I study with Study Smart.

Testimonial person
Tina
Medicine Student
Quotes

I always thought I studied well. My grades were fine. I could never have imagined that applying these study skills would have such a huge and direct impact on my grades, my speed and the pleasure I have in learning.

Testimonial person
Julie
Marketing Student
Quotes

For the first time, I finally feel totally confident about the way I learn. I have the perfect overview and make great progress in terms of speed and the grades I get. Thanks, Chris!

Testimonial person
Matt
Industrial Engineering Student
Quotes

I immediately started to enjoy learning again, and my grades soared. All of a sudden, everything went better. I highly recommend Study Smart to all students..

Testimonial person
Emma
Law Student
Quotes

Being able to create my materials online made the process of studying so much smoother and quicker. I no longer have to spend a huge amount of my time on creating my summaries.

Testimonial person
Michael
Psychology Student
Quotes

At first, my notes were a mess. Now I use Study Smart to take my notes in a perfectly structured way. It helps me to save a lot of time and do other things I enjoy.

Testimonial person
Emily
Teacher
Quotes

Students that study with Study Smart get better grades. The system applies all the learning methods in such a way that both well-performing students and students who struggle perform much better.

Testimonial person
Richard
Literature Student
Quotes

Hi Chris, I would like to thank you very much. Last year I scored C on a course, and this year I got an A+ thanks to your method! Thank you very much!

Testimonial person
Madison
Parent
Quotes

The largest effect is that my child is more enthusiastic about school! Every parent wants their children to be happy at school, Study Smart made it happen.

Testimonial person
Robert
Accountant Student
Quotes

In high school, I failed several exams, and that has really changed now. I actually needed this tool very much back then. Since I started studying with StudySmart, I haven't had any D's. My average score is now an A and those are results I would have never had in the past

Testimonial person
James
Business and Science Student
Quotes

With my old method, I passed only 3 out of 8 courses. Since I started taking my notes digitally in Study Smart, I have passed all my courses on the first try. For me, StudySmart takes away the stress of wondering if I will pass or not.

Testimonial person
Christopher
Veterinarian Student
Quotes

Thanks to StudySmart, I passed all my exams, and with better grades than before! On top of that, I have mastered a very good study method now, which I am confident will help me earn my degree.

List the four broad classes of services that a transport protocol can provide. For each of the service classes, indicate if either UDP or TCP (or both) provides such a service.

a) Reliable data transfer: TCP provides a reliable byte-stream, UDP does not.
b) Guaranteed throughput value: Neither
c) Guaranteed timed delivery: Neither
d) Confidentiality (encrypted): Neither

Recall that TCP can be enhanced with SSL to provide process-to-process security services, including encryption. Does SSL operate at the transport layer or the application layer? If the application developer wants TCP to be enhanced with SSL, what does the developer have to do?

SSL operates at the application layer. The SSL socket takes unencrypted data from the application layer, encrypts it and then passes it to the TCP socket. If the application developer wants TCP to be enhanced with SSL, she has to include the SSL code in the application.

Why do HTTP, FTP, SMTP, and POP3 run on top of TCP rather than on UDP?

The applications associated with those protocols require that all application data be received in the correct order and without gaps. TCP provides this service whereas UDP does not.

Consider an e-commerce site that wants to keep a purchase record for each of its customers. Describe how this can be done with cookies.

When the user first visits the site, the server creates a unique identification number, creates an entry in its back-end database, and returns this identification number as a cookie number. This cookie number is stored on the user’s host and is managed by the browser. During each subsequent visit (and purchase), the browser sends the cookie number back to the site. Thus the site knows when this user (more precisely, this browser) is visiting the site.

Describe how Web caching can reduce the delay in receiving a requested object. Will Web caching reduce the delay for all objects requested by a user or for only some of the objects? Why?

Web caching can bring the desired content ‘closer’ to the user, perhaps to the same LAN to which the user’s host is connected. Web caching can reduce the delay for all objects, even objects that are not cached, since caching reduces the traffic on links.

Why is it said that FTP sends control information “out-of-band”?

FTP uses two parallel TCP connections, one connection for sending control information (such as a request to transfer a file) and another connection for actually transferring the file. Because the control information is not sent over the same connection that the file is sent over, FTP sends control information out of band.

The question on the page originate from the summary of the following study material:

Computer Networking: A Top-down Approach | 9780273768968

View summary
  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo

Summaries related to Application layer