Spring 2015 CSCI 373 Homework 7

This assignment is due in class on 23 April or may be uploaded to Homework 7 on moodle by 11:55 PM on 26 April. If you submit your homework with moodle, you should consider submitting in PDF.

Problems from the textbook

Do the following problems from Chapters 3 and 2 of the textbook. A complete copy of the problems is available from the course moodle page.

Continuing problem of packet format

This is an extension of the last problem of Homework 6.

Continuing problem part 1

Suppose the network has been divided into 16 subnets each using a mask of 28 bits. (Yes, I know this is rather silly.)

How would you express the subnets containing the hosts and

Suppose that every subnet contains a router which contains the binary digits 1110 as the last four bits of its 32-bit IP number. What would be the IP addresses for the routers of the subnets where and are located?

It is OK to use a calculator in this problem. We won’t have problems like this on the exams.

Continuing problem part 2

The MAC address of is 34:17:EB:98:F6:AD, and the MAC address of is 34:17:EB:97:C2:50. The MAC address of’s only router is 00:08:E3:FF:FC:28, and the MAC address of’s only router is 00:08:E3:FF:FC:40.

Suppose an application calls the sendto function of the socket API to send a 2000-byte datagram to port 4444 of host Suppose the application is sending this datagram from port 8888 of host and that the MTU of the network connecting and is 1500 bytes.

In the last problem of Homework 6, you described the contents of any IP packets generated to execute the sendto operation. Extend your answer to include the Ethernet frame prepended to this packet. Use the format of the “Layer 1 Ethernet packet” given on the Wikipedia page but do not include the four octet 802.1Q tag.