The PPP Multilink Protocol (MP)
RFC 1717
Document | Type |
RFC - Proposed Standard
(November 1994; No errata)
Obsoleted by RFC 1990
|
|
---|---|---|---|
Authors | Brian Lloyd , Glenn McGregor , Keith Sklower , David Carr | ||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 1717 (Proposed Standard) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group K. Sklower Request for Comments: 1717 University of California, Berkeley Category: Standards Track B. Lloyd G. McGregor Lloyd Internetworking D. Carr Newbridge Networks Corporation November 1994 The PPP Multilink Protocol (MP) Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document proposes a method for splitting, recombining and sequencing datagrams across multiple logical data links. This work was originally motivated by the desire to exploit multiple bearer channels in ISDN, but is equally applicable to any situation in which multiple PPP links connect two systems, including async links. This is accomplished by means of new PPP [2] options and protocols. Acknowledgements The authors specifically wish to thank Fred Baker of ACC, Craig Fox of Network Systems, Gerry Meyer of Spider Systems, Tom Coradetti of Digiboard (for the Endpoint Discriminator option), Dan Brennan of Penril Datability Networks, Vernon Schryver of SGI (for the comprehensive discussion of padding), and the members of the IP over Large Public Data Networks and PPP Extensions working groups, for much useful discussion on the subject. Table of Contents 1. Introduction ................................................ 2 1.1. Motivation ................................................ 2 1.2. Functional Description .................................... 3 1.3. Conventions ............................................... 3 2. General Overview ............................................ 4 3. Packet Formats .............................................. 6 3.1. Padding Considerations .................................... 9 Sklower, Lloyd, McGregor & Carr [Page 1] RFC 1717 PPP Multilink November 1994 4. Trading Buffer Space Against Fragment Loss .................. 9 4.1. Detecting Fragment Loss ................................... 10 4.2. Buffer Space Requirements ................................. 11 5. PPP Link Control Protocol Extensions ........................ 12 5.1. Configuration Option Types ................................ 12 5.1.1. Multilink MRRU LCP option ............................... 13 5.1.2. Short Sequence Number Header Format Option .............. 13 5.1.3. Endpoint Discriminator Option ........................... 14 6. Closing Member links ........................................ 18 7. Interaction with Other Protocols ............................ 19 8. Security Considerations ..................................... 19 9. References .................................................. 20 10. Authors' Addresses ......................................... 21 1. Introduction 1.1. Motivation Basic Rate and Primary Rate ISDN both offer the possibility of opening multiple simultaneous channels between systems, giving users additional bandwidth on demand (for additional cost). Previous proposals for the transmission of internet protocols over ISDN have stated as a goal the ability to make use of this capability, (e.g., Leifer et al., [1]). There are proposals being advanced for providing synchronization between multiple streams at the bit level (the BONDING proposals); such features are not as yet widely deployed, and may require additional hardware for end system. Thus, it may be useful to have a purely software solution, or at least an interim measure. There are other instances where bandwidth on demand can be exploited, such as using a dialup async line at 28,800 baud to back up a leased synchronous line, or opening additional X.25 SVCs where the window size is limited to two by international agreement. The simplest possible algorithms of alternating packets between channels on a space available basis (which might be called the Bank Teller's algorithm) may have undesirable side effects due to reordering of packets. By means of a four-byte sequencing header, and simple synchronization rules, one can split packets among parallel virtual circuits between systems in such a way that packets do not become reordered, or atShow full document text