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Guilherme Mazui

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What is the Difference Between HDLC and SDLC?

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HDLC (High-Level Data Link Control) and SDLC (Synchronous Data Link Control) are both networking protocols that provide point-to-multipoint interconnection. However, they differ in several ways:

  1. Origin: HDLC is a modified version of SDLC and was developed by ISO from SDLC with some changes.
  2. Orientation: SDLC is a character-oriented protocol, while HDLC is bit-oriented.
  3. Control Information: HDLC contains more control information than SDLC and adds error correction and flow control capabilities to SDLC.
  4. Modes: HDLC introduces two additional modes: Asynchronous Response Mode (ARM) and Asynchronous Balanced Mode (ABM).
  5. Frame Transfer: HDLC enables frames that are not a multiple of 8 bits, while SDLC does not.
  6. Addresses: HDLC enables addresses more than 1 byte, while SDLC does not.
  7. Escape Character: HDLC uses an escape character to indicate when the bit stuffing method should be used, while SDLC does not.

In summary, HDLC is a more advanced version of SDLC, offering additional features and capabilities. While both protocols share the same frame format and have similar field functions, HDLC is more widely adopted and provides better performance in terms of speed and error correction.

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  • What is the Difference Between HDLC and SDLC?
  • Comparative Table: HDLC vs SDLC

    • Comparative Table: HDLC vs SDLC

    HDLC (High-Level Data Link Control) and SDLC (Synchronous Data Link Control) are two data link layer protocols used for transmitting data between network nodes. Here is a table comparing the differences between HDLC and SDLC:

    Characteristic HDLC SDLC
    Usage Frames are used to encapsulate data SDLC packets are used
    Transmission Supports both asynchronous and synchronous transmission Only supports synchronous transmission
    Transfer Modes Supports three transfer modes (Normal Response Mode, Asynchronous Balanced Mode, and Asynchronous Response Mode) Supports only one transfer mode (Normal Response Mode)
    Fault Detection More efficient fault detection Less efficient fault detection
    Bit Division Data is divided into bits before being sent over the network Characters are divided into bits before being sent over the network
    Escape Character Uses an escape character to indicate when bit stuffing should be used Does not use an escape character
    Origin Developed by ISO (International Organization for Standardization) Developed by IBM (International Business Machines Corporation)
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.