Define different modes of operations in TELNET and their efficiency

 Most TELNET implementation operate in one of the three modes  :

1. Default Mode:
2. Character Mode
3.  Line Mode
4. Default Mode:

• The default mode is used IF no other modes are invoked through option negotiation. -
• In this mode, the echoing is done by -the client.
• -The user types a character and the client echoes the character on the screen but does not send it until a whole wine is completed. -
• After sending the whole line to the server the client walks for the GA (go ahead) Command from the server before accepting a new line from the user. 
• The operation is half- duplex, half duplex operation is not efficient when the Top connection itself is full-duplex and so this. mode is becoming obsolete.

        2.Character Mode

• In the character mook, each character typed is sent by the client to server.. The server normally echoes the character back to be displayed on the client screen. In this mode the echoing of the character can be delayed if the transmission time Is long It also creates overhead for the network
• because tries TCP segments must be sent for each character of data: The user enters a character that is sent
• to the server.
• The server acknowledges the received Character echoes the character back The client acknowledges the receipt of the echoed character.

          3.Line Mode

• A new mode has been proposed to compensate for the deficiencies of the default mod and the character mode
• -In this mode called the lime made, line, editing is done by the client .
• The client then sends the whole line to the server. -
• Although the line mode looks like the default mode, it is not.
• -The default mode operates in the half duplex mode; the line mode is full-duplex with the client sending one line after another, without the need for an intervening GA (go ahead) character from the server.