LPWAN Static Context Header Compression (SCHC) and fragmentation for IPv6 and UDP
draft-ietf-lpwan-ipv6-static-context-hc-07
lpwan Working Group A. Minaburo
Internet-Draft Acklio
Intended status: Informational L. Toutain
Expires: April 23, 2018 IMT-Atlantique
C. Gomez
Universitat Politecnica de Catalunya
October 20, 2017
LPWAN Static Context Header Compression (SCHC) and fragmentation for
IPv6 and UDP
draft-ietf-lpwan-ipv6-static-context-hc-07
Abstract
This document describes a header compression scheme and fragmentation
functionality for very low bandwidth networks. These techniques are
specially tailored for LPWAN (Low Power Wide Area Network) networks.
The Static Context Header Compression (SCHC) offers a great level of
flexibility when processing the header fields. SCHC compression is
based on a common static context stored in a LPWAN device and in the
network. Static context means that the stored information does not
change during the packet transmission. The context describes the
field values and keeps information that will not be transmitted
through the constrained network.
SCHC must be used for LPWAN networks because it avoids complex
resynchronization mechanisms, which are incompatible with LPWAN
characteristics. And also because in most cases, IPv6/UDP headers
are reduced to a small identifier called Rule ID. Eventhough
sometimes, a SCHC compressed packet will not fit in one L2 PDU, and
the SCHC fragmentation protocol will be used. The SCHC fragmentation
and reassembly mechanism is used in two situations: for SCHC-
compressed packets that still exceed the L2 PDU size; and for the
case where the SCHC compression cannot be performed.
This document describes the SCHC compression/decompression framework
and applies it to IPv6/UDP headers. This document also specifies a
fragmentation and reassembly mechanism that is used to support the
IPv6 MTU requirement over LPWAN technologies. Fragmentation is
mandatory for IPv6 datagrams that, after SCHC compression or when it
has not been possible to apply such compression, still exceed the L2
maximum payload size. Similar solutions for other protocols such as
CoAP will be described in separate documents.
Minaburo, et al. Expires April 23, 2018 [Page 1]
Internet-Draft LPWAN SCHC October 2017
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. LPWAN Architecture . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Static Context Header Compression . . . . . . . . . . . . . . 7
4.1. SCHC Rules . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Rule ID . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.3. Packet processing . . . . . . . . . . . . . . . . . . . . 10
4.4. Matching operators . . . . . . . . . . . . . . . . . . . 11
4.5. Compression Decompression Actions (CDA) . . . . . . . . . 12
4.5.1. not-sent CDA . . . . . . . . . . . . . . . . . . . . 13
4.5.2. value-sent CDA . . . . . . . . . . . . . . . . . . . 13
4.5.3. mapping-sent . . . . . . . . . . . . . . . . . . . . 13
4.5.4. LSB CDA . . . . . . . . . . . . . . . . . . . . . . . 13
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