What is the full form of FCS?

Introduction

Frame Check Sequence (FCS) is an error-detecting code that is added in a frame in the form of a bit in a communication code.

Frames are the data that are sent in a network communication channel. These frames send data from source to receiver. FCS is sometimes confused with the recovery process but it is an error detection code.

FCS Overview

Frame check sequence is used in the “High-Level Data Link Control (HDLC)” error detection process. It is an extra bit of 2 or 4 bytes that are added to frames for checking errors.

• It checks the error in the control field, address field, and information field.

• It ensures that data frames are error free during data transmission forms sender to receiver.

• It is used in communication code and its size varies from 2 bytes to 4 bytes.

• The type of FCS depends upon the protocol used in networking.

FCS Functionality

It is used in the form of a bit in a frame when data is transmitted in the communication channel. First “frame check sequence” is checked before sending it in frames. Then it is checked and compared at the receiver's end. On matching data transmission completed. If the FCS data do not match the data frame is rejected.

FCS Applications

“Frame Check Sequence” is used in the error detection process and not for the data recovery process.

• FCS is a four-octet cyclic redundancy check that identifies corrupt data in a network frame.

• When any corrupt file is found in data frames during transmission in the communication channel. FCS bits are affixed in data frames as extra data bits. If these bits match at the receiver's end the frame sequence is successful otherwise it is discarded.

• In Ethernet, the data link layer is rejected if any error is found. Then sender sends a message to the receiver using ethernet protocol. These data frames are then divided into small frames and these Frame check sequence bits are attached to the frames in the corrupt area. Then data is transmitted over medium if the frame matches. Ethernet does not retransmit the corrupted file and data lost.

• To detect FCS code different error techniques are used like parity check, checksum, and Cyclic redundancy check.

• FCS is also used in frame relay for detecting data and discarding errors found in the frame relay network.

• FCS also play an important role in LAN access technology from error detection and internet security to removing deleted message and videos.

FCS Importance

Frame check sequences are significant in ensuring that the data frame is error-free and transmitted over the communication channel from sender to receiver. It ensures the address field, information field and control field in the network area are error-free.

Conclusion

In a network communication channel, there are various data transmission mediums over which data is transmitted from sender to receiver. To ensure that data transmitted over medium is error-free is checked various techniques like cyclic redundancy check, checksum and parity bit check. If there is any error found in the data these are corrected by Frame check sequence. These FCS are small frame bits of 2-4 bytes. These bits correct the data frame and are transmitted successfully. If the frame-matched transmission is successful but if failed to match data is lost.

FAQs

Q1. What is the checksum technique?

Ans: The checksum is an error detection technique that is used during data transmission communication channels. Data is divided into multiple sections and these sections are linked by 1 complement arithmetic to get checksum. These checksums are sent to other sections and all the sections are checked at the receiver end using 1 complement. If we get zero at the end then transmission is successful. It is sometimes considered as FCS code for cyclic redundancy check.

Q2. What is Frame Relay and what is the role of FCS in Frame Relay?

Ans: Frame relay is a network that detects errors using Frame check sequence frames. It discards the frame containing the error. The frame relay network does not retransmit the data frame, it is retransmitted by upper-layer protocol to the receiver end. Any specific error recovery is transmitted by network architecture and sent by upper layer protocol. FCS use V.41 16 but a polynomial generator that checks all the bit in the frame and is implemented by hardware.

Q3. What is the role of FCS in internet security?

Ans: The deletion or recording of messages is done by a normal internet module. On deletion of a message, the MAC layer drops any frame received by it and changes it with an invalid frame check sequence. The network module discards these units with IP header errors and replaces them with checksum errors.