Assignment

Problem 1- Packet vs. Circuit-Switched Communications:

(a) Which type of communication is preferable in wireless network operation and describe its service guarantee expectation? Explain your answer in detail.

(b) Give two examples of applications for which circuit switching and packet switching would be more suitable respectively.

Problem 2- IP Fragmentation

Consider sending3000-byte datagram into a link that has an MTU of 500 bytes.

a) How many fragments are generated?

b) What are their characteristics (i.e. what are the flags and offset values for each (Assume that the DF flag was not set : )

Solution: Assume that no optional fields of the IP header are in use (i.e. IP header is 20 bytes)

c) Explain how traceroute works. Include a traceroute to a host at least 30 hops away.

Problem 3: CIDR -A router has the following (CIDR) entries in its routing table:

Address/mask Next hop
135.46.56.0/22 Interface 0
135.46.60.0/22 Interface 1
192.53.40.0/23 Router 1
default Router 2

For each of the following IP address, what does the router do if packets with the following addresses arrives?

(a) 135.46.63.10
(b) 135.46.57.14
(c) 135.46.52.2
(d) 192.53.40.7
(e) 192.53.56.7

Problem 4- NAT

What problem is tackled by Network Address Translation (NAT)? Please briefly describe what NAT does.

Problem 5- IP addresses

How does a host get an IP address? How does a network get the subnet part of an IP address? How does a provider get a block of IP addresses? What is the principle behind these procedures?