Ken Pembleton
Telecommunications
Lab #1 - Wireshark
09/28/15

Wireshark Lab

Part A

1. How many packets (frames) are there in this capture?
499

2. Expand the Internet Protocol triangle of the first frame in the middle pane.

  1. What are the source and destination addresses of this packet?
    2. Source Address: 10.1.3.143
    Destination Address: 10.1.6.18

  2. To what entities do these numbers refer?
    3. IP Addresses

3. Expand the Transmission Control Protocol triangle of the first frame in the middle pane.

  1. What are the source and destination addresses of this packet?
    2. Source Port: 32803
    Destination Port: 1720

  2. To what entities do these numbers refer?
    3. Port Numbers

4. What service is the host at IP 10.1.3.143 trying to access on the host with IP 10.1.6.18?
VoIP

5. H.323 uses a single fixed TCP port (1720) to start a call using the H.225 protocol (defined by H.323 suite) for call control. Once that protocol is complete, it then uses a dynamic TCP port for the H.245 protocol (also defined by the H.323 suite) for capabilities exchange (caps exchange) and channel control. Finally, it opens up two dynamic UDP ports for each type of media that was negotiated for the call (audio, video, far-end camera control, etc.). This first port carries the RTP protocol data (defined by the H.225 specification) and the second one carries the RTCP data (defined by the H.225 specification).

  1. Which frame first accesses port 1720 and, hence, initiates the exchange?
    2. Frame 4

  2. At which frame do the parties shift to using another pair of ports (for the H.245 protocol)?
    3. Frame 12

  3. At which frame do they begin the real-time protocol (RTP) specified by H.225?
    4. Frame 34

Part B

1. Frame 1 - client is requesting an IP address. Expand the Bootstrap Protocol.

  1. What does DHCP stand for?
    2. Dynamic Host Configuration Protocol

  2. What do you think DHCP Discover means?
    3. That the client is trying to discover the device that handles DHCP

2. Frame 2 - expand the Bootstrap Protocol. What do you think DHCP Offer means?
The device that handles DHCP is offering it's service to the client

3. Frame 3 - expand the Bootstrap Protocol. What has the "client" requested of the DHCP server?
An IP Address

4. Frame 4 - The client now has an IP address. What is it?
192.168.1.10

Contact: kpemblet@oswego.edu