Question & Answer: In the first lab, you are only interested in the encoding of the multimedia packets. In the second lab, you…..

DO THIS LAB

In the first lab, you are only interested in the encoding of the multimedia packets. In the second lab, you need to find which transport-layer protocol is used for multimedia.

Part 1: Lab 28.1

To transmit multimedia over the Internet, the information needs to be encoded (compressed). In this lab assignment, you want to find the encoding method of the captured data.

Section A. Internet Radio

Browse the Internet for a live radio station. Start capturing the packets as you are listening to the radio. Save the captured file.

Questions

Using the captured information, answer the following questions

1. Checking the HTTP Get messages, what character set(s) is/are accepted by the receiver?

2. Explain the type(s) of the character set(s) (you may need to do an Internet search).

3. Checking the HTTP Get messages, what encoding algorithm(s) is/are accepted by the receiver?

4. Explain the type of encoding (you may need to do an Internet search).

5. Checking the HTTP OK messages, what character set is used by the sender? Checking the HTTP OK messages, what encoding method is used by the sender?

Section B. Internet Telephony

To complete this portion of the lab, you need to have the Internet Telephony Service to capture the packets during a telephone exchange. Alternatively, you may download a captured VOIP session from 1 of many websites such as this one.

Questions

Using the captured information, answer the following questions on the Lab Assignment 3: Part 1 Lab Report Sheet.

1. Examining RTP packets, what is the payload type?

2. Explain the payload type.

-A screenshot of the supporting captured information.

Part 2: Lab 28.2

Multimedia today uses either TCP or UDP as the transport-layer protocol. Although some Internet radios and TVs use TCP, interactive multimedia mostly uses UDP. In the second case, however, UDP needs to be combined with RTP and RTCP. In addition, interactive multimedia communication needs a kind of signaling system, which mostly is provided by the SIP as discussed in the textbook.

Section A. Internet Radio

Open the captured file you saved from the live radio.

Questions

Using the captured information, answer the following questions

1. Is the service streaming stored audio, live audio, or interactive audio?

2. What transport-layer protocol is used to transmit the audio in the radio station?

3. Do you experience any jitter? What is the reason?

Section B. Live Internet TV

Browse the Internet for a live TV station, such as Al Jazeera Live TV (English version).

Capture packets while you are watching.

. A screenshot of the supporting captured information.