PPP over Simple Data Link (SDL) using SONET/SDH with ATM-like framing (RFC2823)
Original Publication Date: 2000-May-01
Included in the Prior Art Database: 2019-Feb-13
Internet Society Requests For Comment (RFCs)
J. Carlson: AUTHOR [+3]
This document extends methods found in the Point-to-Point Protocol (PPP) and RFCs 1662 and 2615 to include a new encapsulation for PPP called Simple Data Link (SDL). SDL provides a standard method for transporting multi-protocol datagrams over point-to-point links, and RFCs 1662 and 2615 provide a means to carry PPP over Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH) circuits. SDL provides a very low overhead alternative to HDLC-like encapsulation, and can also be used on SONET/SDH links. This memo defines an Experimental Protocol for the Internet community.
Network Working Group J. Carlson Request for Comments: 2823 Sun Microsystems, Inc. Category: Experimental P. Langner Lucent Technologies Microelectronics Group E. Hernandez-Valencia J. Manchester Lucent Technologies May 2000
PPP over Simple Data Link (SDL) using SONET/SDH with ATM-like framing
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2000). All Rights Reserved.
The Point-to-Point Protocol (PPP)  provides a standard method for transporting multi-protocol datagrams over point-to-point links, and RFCs 1662  and 2615  provide a means to carry PPP over Synchronous Optical Network (SONET)  and Synchronous Digital Hierarchy (SDH)  circuits. This document extends these standards to include a new encapsulation for PPP called Simple Data Link (SDL) . SDL provides a very low overhead alternative to HDLC-like encapsulation, and can also be used on SONET/SDH links.
This specification is intended for those implementations that use PPP over high speed point-to-point circuits, both with so-called "dark fiber" and over public telecommunications networks. Because this enhanced PPP encapsulation has very low overhead and good hardware scaling characteristics, it is anticipated that significantly higher throughput can be attained when compared to other possible SONET/SDH payload mappings, and at a significantly lower cost for line termination equipment.
Carlson, et al. Experimental [Page 1]
RFC 2823 PPP SDL on SONET/SDH May 2000
SDL is defined over other media types and for other data link protocols, but this specification covers only the use of PPP over SDL on SONET/SDH.
The use of SDL requires the presentation of packet length information in the SDL header. Thus, hardware implementing SDL must have access to the packet length when generating the header, and where a router’s input link does not have this information (that is, for non-SDL input links), the router may be required to buffer the entire packet before transmission. "Worm-hole" routing is thus at least problematic with SDL, unless the input links are also SDL. This, however, does not appear to be a great disadvantage on modern routers due to the general requirement of length information in other parts of the system, notably in queuing and congestion control strategies such as Weighted Fair Queuing  and Random Early Detect .
This document is not a replacement for the existing HDLC-like framing mandated by RFC 2615 . Instead, the authors intend to gain implementation experience with this technique for operational and performance evaluation purposes, and would like to hear from others either considering or using the protocol as described in this document. Please see Section 14 of this document for contact...