Voip

NETW250 Week 3 iLab: Observing VoIP Protocols Using Wireshark

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Professor’s Name:

Date:

Task 2: Filter and Examine RTP Packets

6. In the Tree View section (i.e., the middle section), click on the plus box next to the Real-Time Transport Protocol header and expand it.

* What’s the value of the Payload type field? _____

* What’s the value of the Sequence number field? _____

* What’s the value of the Timestamp field? _____

* Capture a screenshot of the Wireshark window with RTP header details above, and paste the image into the lab report here. |

7. Go back to the Packet List Section and select the next RTP packet. In the Tree View section, click on the plus box next to the Real-Time Transport Protocol header and expand it.

* What’s the value of the Payload type field? _____

* What’s the value of the Sequence number field? _____ (Hint: this number should be one up the previous sequence numbers; otherwise, you chose the wrong packet.)

* What’s the value of the Timestamp field? _____

* Subtract the timestamp value from Step 6 from the timestamp value here to determine the unit of time contained in each packet. _____

* The captured call in this iLab uses the default G.711 codec, which generates 8,000 samples every second. Typically, the RTP timestamp clock rate is the same as the sampling rate. Therefore, the RTP timestamp clock increments once for each byte or sample.

* If each increment of the RTP timestamp clock (i.e., one unit) represents 1/8,000 of a second, how many milliseconds of conversation are carried in each RTP packet? _____

* Given the payload bit rate of G.711 codec as 8,000 bits per second, the payload size in milliseconds calculated above can also be represented in _____ bits or _____ bytes.

* Capture a screenshot of the Wireshark window with RTP header details above, and paste the image into the lab report here. |

8. Go back to the Packet List Section and...