COMPUTER NETWORKS

An Investigation on Current Networking Technologies

An Investigation on Current Networking Technologies

Question 1 (a)

Answer

The layered protocol architecture is used in the computer networks and data communication because of the following two reasons:

Simplicity of infrastructure design. The layered approach of protocol architecture provides the network designing process with the easiness and simplicity by providing each layer a separate and distinguished function. However, all the layers are inter-related.

Another very important reason for using the layered approach of protocol architecture is that troubleshooting is easier. When using the layered protocol architecture, it is easier to diagnose the problem in the network. Problem is diagnosed by step by step testing on each layer.

Question 1 (b)

Answer

The main difference between the bridge and router is that a bridge operates at the Layer-2 (Data Link Layer) of the OSI Model, whereas a router operates on the Layer-3 (Network Layer) of the OSI Model. A bridge does not understand any protocol, and it works on the MAC address. A bridge is used to connect several hosts over a single LAN.

The purpose of router is to choose the best path for passing the IP packets. Routers work on several communication protocols such as TCP/IP, and IPX/SPX. A router is basically used to pass the IP packets between two physically different networks.

The main limitation of using a bridge is that it a bridge is unable to recognize any broadcast or multicast traffic, and therefore does not filter the broadcast or multicast traffic. Whereas, a router blocks the broadcast traffic and therefore, it is used to secure the network from the broadcast storms.

Question 2

Answer

At time t0, the sending host begins to transmit. At time t1 = L/R1, the sending host completes transmission and the entire packet is received at the router (no propagation delay). Because the router has the entire packet at time t1, it can begin to transmit the packet to the receiving host at time t1. At time t2 = t1 + L/R2, the router completes transmission and the entire packet is received at the receiving host (again, no propagation delay). Therefore, the total end-to-end delay is L/R1 + L/R2 = L*(R1 + R2)/(R1*R2).

Question 3

Answer

IPSec (short for IP Security) is a set of protocols to protect data transmitted over the IP, allows for authentication and / or encryption of IP-packets. IPsec also includes protocols for the secure exchange of keys in a network the Internet. Mainly used for the organization ...