Page 205 - DCAP406_DCAP_207_Computer Networks

Computer Networks/Networks

Notes Processes: Program and process are distinct. A program is code that describes all the variables
and actions to be performed on those variables while a process is an instance of the program.
Proxy Server: The proxy server acts like as a buffer between the client’s web browser and the
web server to provide the web browser’s request without involving the original web server.
Raw Sockets: They are designed for applications like ICMP or OSPF that directly use the services
of IP in such cases neither stream socket nor datagram socket be used.
Reserved Ports: The port numbers 0-1023 are reserved for the superuser and remaining ports
starting from 1024 are for other users.

Round Trip Time (RTT): It is the time taken to send a packet to web server and receive a response
from the web server.
Server: Like client, server is also a software entity that runs on a remote machine and provides
requested services to client machines.
Simple Mail Transfer Protocol (SMTP): Enables a client machine to exchange mail and message
between TCP/IP hosts.

12.7 Review Questions

1. Write a short note on DNS.
2. What are HTTP connections and how do they differ?
3. What are different types of user server identification? Explain them briefly.

4. How is www different from Internet? Explain.
5. How does SMTP work in transferring mails from one computer system to another computer
system attached to different networks?

6. What is a web server? How does it function?
7. Describe the differences and similarities between a URL and an e-mail address.
8. Describe how e-mail is stored and transmitted by POP and SMTP servers.

9. Explain the concept of multimedia? What are the various components of multimedia?
Answers: Self Assessment

1. ASCII 2. mail server
3. Group names/mail exploders 4. decimal
5. DNS 6. SMTP
7. True 8. False

9. True 10. False
11. True 12. False
13. True 14. False
15. True

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