Internet-Draft SCHCoPPP December 2019
Thubert Expires 5 June 2020 [Page]
5172 (if approved)
Intended Status:
Standards Track
P. Thubert, Ed.
Cisco Systems



This document extends RFC 5172 to signal the use of SCHC as the compression method between a pair of nodes over PPP. Combined with RFC 2516, this enables the use of SCHC over Ethernet and Wi-Fi.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 5 June 2020.

Table of Contents

1. Introduction

The Point-to-Point Protocol (PPP) [RFC5172] provides a standard method of encapsulating network-layer protocol information over point-to-point links. "A Method for Transmitting PPP Over Ethernet (PPPoE)" [RFC2516] transports PPP over Ethernet between a pair of nodes. It is compatible with a translating bridge to Wi-Fi, and therefore enables PPP over Wi-Fi as well.

PPP also defines an extensible Link Control Protocol, and proposes a family of Network Control Protocols (NCPs) for establishing and configuring different network-layer protocols. "IP Version 6 over PPP" [RFC5072] defines the IPv6 Control Protocol (IPV6CP) , which is an NCP for a PPP link, and allows for the negotiation of desirable parameters for an IPv6 interface over PPP.

"Negotiation for IPv6 Datagram Compression Using IPv6 Control Protocol" [RFC5172] defines the IPv6 datagram compression option that can be negotiated by a node on the link through the IPV6CP. The "Static Context Header Compression (SCHC) and fragmentation for LPWAN, application to UDP/IPv6" [SCHC] is a compression and fragmentation technique that was defined after the publication of [RFC5172]. In order to enable SCHC over PPP and therefore Ethernet and Wi-Fi, [RFC5172] must be extended to signal SCHC as an additional compression method for use over PPP.

2. BCP 14

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119][RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Extending RFC 5172

[RFC5172] defines an IPV6CP option called the IPv6-Compression-Protocol Configuration option with a type of 2. The option contains an IPv6-Compression-Protocol field value that indicates a compression protocol and an optional data field as shown in Figure 1:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   |     Type      |    Length     |   IPv6-Compression-Protocol   |
   |    Data ...
Figure 1: The IPv6-Compression-Protocol Configuration Option

This specification indicates a new IPv6-Compression-Protocol field value for [SCHC] (see Section 5, and enables to transport a Uniform Resource Identifier (URI) [RFC3986] of the set of rules in the optional data. The default format for the set of rules is YANG using the "Data Model for SCHC" [SCHC_DATA_MODEL] encoded in JSON as specified in [RFC7951]. If the encoding is asymetrical, the initiator of the session is considered downstream, playing the role of the device in an LPWAN network.

4. Security Considerations

This draft enables to use the SCHC compression and fragmentation over PPP and therefore Ethernet and Wi-Fi with PPPoE. It inherits the possible threats against SCHC listed in the "Security considerations" section of [SCHC].

5. IANA Considerations

This document requests the allocation of a new value in the registry "IPv6-Compression-Protocol Types" for "SCHC". A suggested value is proposed in Table 1:

Table 1: IP Header Compression Configuration Option Suboption Types
Value Description Reference
4 Static Context Header Compression (SCHC) This document

6. Acknowledgments

7. Normative References

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Mamakos, L., Lidl, K., Evarts, J., Carrel, D., Simone, D., and R. Wheeler, "A Method for Transmitting PPP Over Ethernet (PPPoE)", RFC 2516, DOI 10.17487/RFC2516, , <>.
Varada, S., Ed., Haskins, D., and E. Allen, "IP Version 6 over PPP", RFC 5072, DOI 10.17487/RFC5072, , <>.
Varada, S., Ed., "Negotiation for IPv6 Datagram Compression Using IPv6 Control Protocol", RFC 5172, DOI 10.17487/RFC5172, , <>.
Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and J. Zuniga, "Static Context Header Compression (SCHC) and fragmentation for LPWAN, application to UDP/IPv6", Work in Progress, Internet-Draft, draft-ietf-lpwan-ipv6-static-context-hc-23, , <>.

8. Informative References

Minaburo, A. and L. Toutain, "Data Model for Static Context Header Compression (SCHC)", Work in Progress, Internet-Draft, draft-ietf-lpwan-schc-yang-data-model-00, , <>.
Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, , <>.

Author's Address

Pascal Thubert (editor)
Cisco Systems, Inc
Building D, 45 Allee des Ormes - BP1200
06254 Mougins - Sophia Antipolis