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In networking, and more specifically in serial point-to-point communication (e.g. HDLC or PPP), is there any accepted terminology for the process or the entity that converts a stream of bytes (e.g., from a serial RS-232 link) into frames (e.g. HDLC frames) for further processing by higher network layers?

I have come across different potential terms, e.g. "framer", "parser", "decoder", ... but these might actually have different established meanings and I am not sure whiche one is appropriate.

areslagae
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  • That would be the Data-Link Layer protocol. HDLC or PPP itself. – Ron Maupin Jul 21 '17 at 14:01
  • Actually, I am only referring to a part of the data link layer, more specifically the part that assembles frames from bytes received from the physical layer using byte stuffing and error detection but not the part that does higher-level functions of the data link layer such as flow control. – areslagae Jul 21 '17 at 15:41
  • In some protocols (IEEE LAN protocols, e.g. ethernet), that would be the MAC sublayer, but protocols like HDLC don't have that, and it is inherent in the protocol itself. PPP calls it an encapsulation component, separate from the LCP and NCP. – Ron Maupin Jul 21 '17 at 16:44

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What you are asking about is actually the purpose of HDLC, which is more of a concept than a standard. Each vendor implements it own version of HDLC, and they are not compatible with each other. HDLC is designed to frame a stream of bits, and the encapsulation parts of other Data-Link Layer protocols are modeled after HDLC.

The IEEE LAN protocols use a MAC (Media Access Control) sublayer to perform framing.

PPP uses what is called an encapsulation component to perform framing.

Both the IEEE LAN protocols and PPP modeled their respective framing components after HDLC, which itself is a framing component.

Ron Maupin
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  • Please allow me to clarify. I am making a software library with a set of components for communication between embedded systems. I am wondering if there is an established terminology for a software component that processes bytes receives from the physical layer (RS232 in my case) into frames. The exact operations are recognizing frames, removing frame delimiters, byte unstuffing and checking and removing the FCS field. Operations not included are higher-level operations in the data link layer such as flow control and error recovery. I'd like to choose a name that make also sense for others. – areslagae Jul 21 '17 at 19:01
  • The hardware will send a stream of bits. HDLC was designed to do exactly what you say. HDLC will not have anything separate because that is the purpose of HDLC. For PPP, that would be the encapsulation component that is based on HDLC. I know of no generic name that encompasses all Data-Link Layer protocols, although the PPP encapsulation component sounds pretty generic. – Ron Maupin Jul 21 '17 at 19:11
  • @areslagae, to put it another way,, the DLC in HDLC stands for Data Link Control. The first standard for HDLC was "_ISO 3309 – Frame Structure_." HDLC, itself, is the entity that does framing, and that is the whole point of HDLC, to frame the stream of bits. There's really not much else to it. – Ron Maupin Jul 21 '17 at 22:28