Briefly explain the following communication tasks Routing Sy

Briefly explain the following communication tasks: Routing Synchronization Flow control What is the major function of the network access layer? What are the fields in the UDP header? What are their purposes? Name any three field of the TCP header and state their purposes. What is the difference between analog and digital signals? Consider a channel with spectrum between 4 MHz and 6 MHz and SNR_dB = 20. Using Shannon\'s formula, what is the maximum capacity of the channel? Based on Nyquist\'s formula how many signaling levels are required? Express the following in their simplest form. Provide explanations supporting your answers. A sin(2 pi ft + pi)+A sin(2 pi ft - pi) A sin(2 pi ft) + A sin(2 pi ft - pi) Consider two functions F_1(t) and F_2(t) with periods 2 seconds and 3 seconds respectively. What is the period of the function F(t) = F_1(t) + F_2(t). What is the relationship between a signal\'s spectrum and its bandwidth? Name and explain three significant transmission impairments.

Solution

1)

i) Routing:

The process of selecting best paths in a network is called Routing. It is also the process of moving data from one host computer to another. It is nothing but getting information packets where they need to go.

ii) Synchronization:

Does the communication system performs well or not is determined by the acuracy of Synchronization.

iii) Flow Control:

The management of data flow among computers or devices or among nodes in a network as the data can be handled at an efficient time is called Flow control.

2) Major Functions of Network Access Layer:

The Network Access Layer is the lowest logical layer in the model. Its major function is to provide specifications for in which way the data bits should move over the network. The other function performed at this layer are encapsulation of IP datagrams into frames which is to be transmitted by the network and mapping of IP addresses to physical layer addresses.

3) The fields in the UDP header are:

The Source port is used as service access point by the UDP packets of the client to represent the session on the local client that originated the packet.

The Destination port is used as service access port by the UDP packets of the client to represent the service required from the remote server.

UDP length is the number of bytes which contains the combined UDP header information and payload data.

UDP Checksum is used in the verification of whether the end to end data has not been corrupted by the routers or bridges in the network.

4) The three fields of TCP header are:

Sequence number in header is the sequence number of the first byte of the payload of the TCP segment.

Acknowledgement number is contained by the TCP segment. It is nothing but the sequence number of the next byte that the sender of the acknowledgement expects to receive from the remote host. The acknowledgement number is only valid when the ACK flag of TCP header is set.

Window is a16 bit field used by the TCP receiver to represent the current size of its receive window. It is expressed in bytes.

5) The difference between analog and digital signal is:

Analog Signals	Digital Signals
It can take any value in a given range.	It can take only one of a discrete set of values.
It has infinite resolution.	It has finite resolution.
Removal of noise is difficult.	Removal of noise is easier.
It is a continuous eelectrical signal.	It is a non-continuous electrical signal.