An organisation has been granted a block of addresses with the mask /26. If the organisation creates 8 equal-sized subnets, how many addresses (including the special addresses) are available in each subnet? Show your calculations.
Give an example of a valid classful address that has the mask 255.255.0.0.
A subnetwork has the range of addresses: 220.127.116.11 to 18.104.22.168 inclusive. What is the direct broadcast address of this subnet?
What is the size of the IPv4 header with 15 bytes of options?
Explain why IPv4 datagrams contain a checksum, but IPv6 datagrams do not.
What is the difference between a well-known port number and an ephemeral port number apart from their numeric ranges?
In your own words, briefly explain the function of the garbage collection timer in RIP.
What is the difference in function between the primary and the secondary DNS servers?
In a Wi-Fi network, what is an “access point”?
What is the function of the default route entry in a routing table?
When a router consults ARP during the forwarding process, what information is it looking for?
What is the purpose of the hop limit field in the base header of an IPv6 datagram?
A classless address was given as “22.214.171.124”. What information is missing and why is it critical?
What is the size of the base header in IPv6 expressed in bytes?
Question 1 4 Marks
An organisation has been allocated the following block of classless addresses by its ISP:
Identify the address in this block that would be used as the network address, the range of addresses that can be used by network hosts, and the address that would be used as the direct broadcast address.
Question 2 4 Marks
A company has been granted a block of addresses which starts at 126.96.36.199/23. Create the following 6 subnets by calculating the subnet address for each subnet.
(a) 2 subnets with 64 addresses each
(b) 4 subnets with 32 addresses each
Question 3 2 Marks
A router receives a packet, and must now process the header to determine how to forward the packet. List any two of the logical processes the router would complete in order to reach a correct forwarding decision.
Question 4 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.
Question 1 6 Marks
Briefly describe in your own words the routing table construction techniques known as address aggregation and longest mask matching and outline the main advantage in using each of these schemes.
Question 2 6 Marks
Contrast the cost metrics between distance vector routing algorithms and link state routing algorithms for building routing tables, and compare two major routing protocols that use them.
Question 3 6 Marks
Explain in your own words how Network Address Translation (NAT) helped to alleviate the IPv4 address shortage.
Question 4 6 Marks
Briefly describe the two addressing schemes called ‘tunnelling’ and ‘header translation’ in terms of their use during the ipv4-to-ipv6 transition period.