Computer Networks ( UDP Client And Server )

Using the wireshark trace and what you have learned so far, answer the following questions (your answers MUST be consistent with that shown in the wireshark trace you hand in):

1. What packet number corresponds to the echo request from client? ________________

2. What packet number correspond to the echo response from server? _________________

3. What is the IP address of the client? __________________________________________

4. What is the IP address of the server? ________________________________________

5. What port is the client listening on? __________________________________________

6. What port is the server listening on? ___________________________________________

7. When the client sends the packet to the server, what layer in the Internet architecture and what specific protocol in the protocol stack adds the port information to the packet? Layer (Application/Transport/Network/Link):___________________________________

Protocol (TCP/UDP/IP/Ethernet/WiFi): ________________________________________

8. When the client sends the packet to the server, what layer in the Internet architecture and what specific protocol in the protocol stack adds the IP address information to the packet? Layer (Application/Transport/Network/Link):___________________________________

Protocol (TCP/UDP/IP/Ethernet/WiFi): ________________________________________

9. In echo requests, what is the source port in the packet referring to: client or server? _____________________________________________________________________

10. In echo requests, what is the destination port in the packet referring to: client or server? _____________________________________________________________________

11. In echo responses, what is the source port in the packet referring to: client or server?_ ____________________________________________________________________

12. In echo responses, what is the destination port in the packet referring to: client or server?_ ____________________________________________________________________

13. The echo client is able to reach the echo server because the IP address and port are known a priori. How does the server learn the client IP address and port for echo responses? Be explicit. (2) ______________________________________________________________________________________________________________________________________________________

14. What application data does the echo client send to the server and what is its length in bytes? (2) __________________________________________________________________

15. What application data does the echo server send to the client and what is its length in bytes? (2)___________________________________________________________________

Time Source 127.8.8.1 127.0..1 Desination 127.8..1 127.8.91 Protocol Length Info 68 23.841120 UDP 38 129 59211 Len-10 b Frame 67: bytes on wire (640 bits), 42 bytes captured (336 bits) on interface 0 Null/Loopback P Internet Protocal Version 4, Src: 127.8.8.1, Dst: 127.8.a.1 4 User Datagran Protocol, 5rc Port: 59211, Dst Port: 12000 Source Port: 59211 Destination Port: 12900 Length: 18 Checksu: Sxfe25 [unverified] [Checksum Status: Unverified] [Strean index: 1] p Data (1e bytes)