Pharos University in Alexandria
Faculty of Engineering
Pharos University in Alexandria
Communications and Computer Networks
Sheet 7
Communications and Computer Networks
Course Code: CE 363
Faculty of Engineering
Lecturer: Dr. Amr Elsaadany
Computer Engineering Department
T.A: Eng. Nehal Fathi
Sheet 7
1. What would be the advantages of having a large MTU? What would be the
advantages of having a small MTU?
2. Can the value of the header length in an IPv4 packet be less than 5? When is it
exactly 5?
3. The size of the option field of an IPv4 datagram is 20 bytes. What is the value of
HLEN? What is the value in binary?
4. An IPv4 datagram has arrived with the following information in the header (in
hexadecimal):
Ox45 00 00 54 00 03 00 00 20 06 58 50 7C 4E 03 02 B4 0E 0F 02
a. Is the packet corrupted?
b. Are there any options?
c. Is the packet fragmented?
d. What is the size of the data?
e. How many more routers can the packet travel to?
f. What is the identification number of the packet?
g. What is the type of service?
5. Determine which of the following states are true and which are
false
a. The total length field defines the total length of the datagram including the header.
b. Communication at the network layer in the Internet is connection oriented.
c. The value of the MTU depends on the physical network protocol.
d. The data link layer is responsible for host-to-host delivery and network layer is
responsible for hop-to-hop delivery.
Pharos University in Alexandria
Faculty of Engineering
Communications and Computer Networks
Sheet 7
6. List three transition strategies to move from IPv4 to IPv6. Explain the difference between tunneling
and dual stack strategies during the transition period. When is each strategy used?
7. A 1360 bytes long message is delivered to the IP layer of a host machine H1. H1 is located on an
Ethernet network and it is to send the message to another host H2.
Work out the structure of the datagram that will be created by the IP layer. Specify the value of each one of the following
fields in the datagram.
VERS, HLEN,TOTAL LENGTH,FLAGS,FRAGMENT OFFSET, HEADER CHECKSUM
Please specify the values in the decimal number system only.
IP addresses of H1 and H2 are 78.100.85.135 and 131.112.50.28.
Given that IDENTIFICATION is to begin from 17 and that no OPTIONS are to be used. Take SERVICE TYPE = 0, TTL =
20 and PROTOCOL = 6. The four field values are given in decimal numbers only.
8. An IP datagram has arrived with the following information in the header.:
(The data is given in Hexadecimal system.)
45 00 00 54
00 03 00 00
20 06 00 00
7C 4E 03 02
B4 0E 0F 02
a)
b)
c)
d)
e)
Are there any OPTIONS?
Is the packet fragmented?
What is the size of the data?
How many routers can the packet travel to?
What is the identification number of the packet?