Question

• a. Identify which of the following statements are correct and which are not correct. Write a correct alternative statement for those which are not correct.

• I. it is more expensive to install fibre-optic cable because specialist training is necessary

• ii. routers are used to connect subnets on a LAN

• iii. all traffic in a subnet passes through the default gateway

• iv. a layer 3 switch provides routing using MAC addresses

• v. computers and/or other devices that are networked in a single physical location are said to form a wide area network.

• b. With the aid of a table similar to Table 1, indicate at which layer number and layer name of the OSI model the protocols ATM, DNS, IP and UDP would be found.

Table 1

Layer number	Layer name	Protocol

• c. What is the network ID of the host with an IPv4 address 192.88.77.150 with a subnet mask of 255.255.255.224?

Answer 1

a)

1)Correct. Installing fibre-optics need specialists. So there will be increase in installation cost

2)Incorrect . No router is needed. Just set subnet to 255.255.0.0

And keep the default gateways the same as they are now.

3)Incorrect . It depends on networkconfiguration. If ip addresses are on the same subnet no need to go through the gateways.

4)Incorrect .Layer 3 uses IP addresses not MAC addresses.

5)Incorrect. It is called as LAN.

b)DNS found at Application layer (layer 7), UDP found at layer 4 (Transport layer),IP found at Network Layer(layer 3) , ATM maps to network layer,data link layer, and physical layer.

c) From mask we can get netmask of 27 i.e... 11111111.11111111.11111111.111 00000

we need to do AND operation between netmask and ip in binary ....

we will get 11000000.01011000.01001101.100 00000 it is nothing but network id.(192.88.77.128/27)