PPP Magnalink Variable Resource Compression (RFC1975)
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2019-Feb-14
Internet Society Requests For Comment (RFCs)
D. Schremp: AUTHOR [+2]
The Magnalink Variable Resource Compression Algorithm (MVRCA) allows a wide range of interoperable compression implementations whose performance characteristics are a function of available CPU and memory resources. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.
Network Working Group D. Schremp Request for Comments: 1975 J. Black Category: Informational J. Weiss Magnalink August 1996
PPP Magnalink Variable Resource Compression
Status of This Memo
This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
The Point-to-Point Protocol (PPP)  provides a standard method of encapsulating multiple protocol datagrams over point-to-point links. The PPP Compression Control Protocol  provides a method for negotiating data compression over PPP links.
The Magnalink Variable Resource Compression Algorithm (MVRCA) allows a wide range of interoperable compression implementations whose performance characteristics are a function of available CPU and memory resources.
The Magnalink variable resource compression algorithm defines a family of interoperable compression solutions with compression performance as a function of available CPU and memory resources. It addresses the need for an algorithm which can be tailored to the system on which it is implemented without compromising interoperability.
Source licenses are available on a non-discriminatory basis.
The contact person for evaluation under NDA and Licensing is:
Director of OEM Sales Magnalink Communications Division Telco Systems Inc. 63 Nahatan Street Norwood, Mass. 02062 Phone: (617) 255-9400, Fax: (617) 255-5885 email@example.com
Schremp, Black & Weiss Informational [Page 1]
RFC 1975 PPP Magnalink Variable Resource Compression August 1996
Before any MVRCA packets may be communicated, PPP must reach the Network-Layer Protocol phase, and the Compression Control Protocol must reach the Opened state.
The text of a Packet to be compressed begins with PPP Protocol number. The Packet header including the PPP Protocol number may have already been compressed when Protocol-Field-Compression has been negotiated.
Reliability and Sequencing
MVRCA packets may be sent across an unreliable link or may use a reliable link as described in "PPP Reliable Transmission" if the reliable link has been negotiated. If frames are delivered out of order or a frame is dropped, the decompressor will detect this and requests a resynchronization using the Reset-Req and Reset-Ack types of the CCP, with the compressor for the affected context.
Although the compression algorithm may occasionally expand a data packet, there is no expansion in MVRCA since any expanded data is instead sent uncompressed. Dictionary synchronization is maintained across uncompressed packets.
The encapsulation consists of the PPP Protocol Identifier, a bit to indicate if the data is compressed, the Context Identifier(CID), a proprietary flag bit (E), a Packet Integrity Byte(PIB), and the Compressed data.
0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PPP Protocol Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...