High-level data link control (HDLC) and Point-to-Point(PPP) are two different data link layer protocols used in computer networks. the primary difference between HDLC and PPP is that HDLC is a bit-oriented protocol whereas PPP is a byte-oriented protocol.
What is HDLC?
Related Article: Difference Between HDLC and SDLC
What is PPP?
PPP stands for point-to-point protocol, it is another WAN encapsulation protocol that is based on HDLC, but it is an improved version of HDLC. When compared to HDLC, PPP has a plethora of additional features.
Related Article: Difference between SLIP and PPP
Difference between HDLC and PPP | HDLC vs PPP:
- HDLC is a bit-oriented protocol, whereas PPP is both byte-oriented and bit-oriented due to its ability to be transmitted over dial-up modem lines as well as true bit-oriented HDLC.
- HDLC does not support link authentication, whereas PPP does.
- HDLC operates at layer 2 called as data link layer, while the PPP is operating at layer 2, and layer three is called the network layer.
- PPP can dynamically assign and free up IP addresses based on their use. In HDLC however, this is not the case.
- In HDLC only synchronous media can be used, PPP can work with both synchronous and asynchronous media.
- HDLC interoperability between non-cisco devices is not possible. This limitation of HDLC, however, is removed from the PPP protocol.
- HDLC lacks an error detection method, whereas PPP employs FCS to detect errors while transmitting data.
- HDLC protocols have two types via ISO, HDLC, and CISCO HDLC, while the PPP uses HDLC a format as defined by ISO.
- HDLC is used to encapsulate data without the assistance of other encapsulation protocols, whereas PPP can encapsulate data without the assistance of other encapsulation protocols such as HDLC and SDLC.
- HDLC fails to check for the quality of the link established, while the PPP uses link control protocol to check for the quality of the established link.
- HDLC does not support authentication. It fails to provide authentication between two nodes. While the PPP supports authentication using a protocol such as PAP and CHAP.
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