What Is The Function Of The Crc Value That Is Found In The Fcs Field Of a Frame??

What Is the Function of The Crc Value That Is Found in The FCS Field of a Frame??

Answer:

• Uphold the physical address
• Support the logical address in the frame
• Back up the unification of the received frame
• Calculate the sum of the header for the data field

In comparison to the CRC value of the frame, the CRC value in the FCS field of a frame is used for the verification of the unification of the received frame. If the two values ​​do not match, the frame is discarded.

Frame check sequence (FCS):

FCS is the code used to detect the error in a communication protocol. Frame check sequence is used to send payload data from the source to the target place.

The basic purpose of FCS:

Within the Frame check sequence all the fields, bytes, and bites are supported to error from the different sources. Based on the data in the frame a number in the FCS field is calculated by the node source. The number is added up to the frame end that is sent. When data is received at the destination, the FCS number is recalculated and then compared to the FCS number in the frame. The frame is discarded if the two vales come different.

Frame check sequence is responsible for error detection only. The error must be corrected by different means. For example, Ethernet talks about the broken frame but does not specify any act or action on how the frame can be retransferred. Transmission Control Protocol is responsible for error recovery, stimulating retransmission, and the loss of data.

Application:

The FCS is transmitted in a way that the receiver calculates the sum over the whole frame with the trailing FCS expected to see a fixed result if it is correct. The standard data sent for Ethernet and other protocols like IEEE 802 is the least significant bit with the FCS the data sent is significant (31 bit). An alternative way is to reverse the FCS in this way it can send the least significant bit 0.

Types:

• Cyclic redundancy check CRC (32 bit)
• X.25 (32 or 16 bit)
• HDLC (32 or 16 bit)
• Frame relies upon (16 bit)
• Point-to-point protocol (32 or 16 bit).