An organisation has been granted a block of class C addresses. If the organisation has 4 equal-sized subnets, how many addresses are available in each subnet?
What is the default mask for a class C network in CIDR notation?
An IPv4 router receives a datagram which is bigger than the Maximum Transfer Unit of the next network. Under what condition can the router fragment this packet?
What is the maximum size of the IPv4 TCP header?
Which field in the IPv6 header can point to the extension header?
Client processes use which kind of port number?
Which address would a router use to send a packet to all other hosts on its subnet?
How many equal-sized subnets can be created in a class C network by a subnet mask of /26?
How many sequence numbers are consumed by a SYN+ACK segment that is carrying no data?
Which timer schedules the sending out of regular update messages in RIP?
When is a DNS response classified as non-authoritative?
What is the purpose of the hop limit field in the base header of an IPv6 datagram?
How does the destination know whether a datagram received is fragmented or not?
What is the last entry in a routing table?
PART B 15 MARKS
Question 1 4 Marks
A company has been granted a block of addresses, one of which is 22.214.171.124/22.
a) How many addresses are available in this block?
b) What is the netmask in dotted decimal notation?
c) What is the first address in this block?
d) What is the last address in this block?
e) How many bits are allocated to hosts?
Question 2 6 Marks
From the block given in the previous question, the company wants to create 8 subnets: 4 subnets with 128 addresses each, and 4 subnets with 64 addresses each.
a) For each of the 8 subnets, show the subnet mask in dotted decimal notation, the first address, and the last address, with the correct prefix notation.
b) How many addresses are left over (unallocated) after the 8 subnets have been created?
Question 3 5 Marks
The figure below shows the configuration of a hypothetical section of the Internet.
Construct the routing table of router R2 for this configuration by copying and completing the following table in the Examination Answer Booklet.
The IPv4 classful architecture has been wasteful and led to the rapid depletion of IPv4 addresses worldwide. Discuss how fixed-length classful addressing affects organisations in terms of address allocation, and how sub-netting, super-netting, and Classless Inter-Domain Routing (CIDR) helps alleviate the problem.
Contrast the cost metrics between distance vector routing algorithms and link state routing algorithms for building routing tables, and briefly name and summarize the two major routing protocols that use them.
Briefly describe the routing table entries of an IPv6 router.
Briefly describe the Zone Routing Protocol (ZRP) used for routing in ad hoc wireless networks.