draft-ietf-6lo-paging-dispatch-04.txt   draft-ietf-6lo-paging-dispatch-05.txt 
6lo P. Thubert, Ed. 6lo P. Thubert, Ed.
Internet-Draft Cisco Internet-Draft Cisco
Updates: 4944 (if approved) R. Cragie Updates: 4944 (if approved) R. Cragie
Intended status: Standards Track ARM Intended status: Standards Track ARM
Expires: March 13, 2017 September 9, 2016 Expires: April 15, 2017 October 12, 2016
6LoWPAN Paging Dispatch 6LoWPAN Paging Dispatch
draft-ietf-6lo-paging-dispatch-04 draft-ietf-6lo-paging-dispatch-05
Abstract Abstract
This specification updates RFC 4944 to introduce a new context switch This specification updates RFC 4944 to introduce a new context switch
mechanism for 6LoWPAN compression, expressed in terms of Pages and mechanism for 6LoWPAN compression, expressed in terms of Pages and
signaled by a new Paging Dispatch. signaled by a new Paging Dispatch.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 13, 2017. This Internet-Draft will expire on April 15, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Updating RFC 4944 . . . . . . . . . . . . . . . . . . . . . . 3 3. Updating RFC 4944 . . . . . . . . . . . . . . . . . . . . . . 3
4. Page 1 Paging Dispatch . . . . . . . . . . . . . . . . . . . 4 4. Page 1 Paging Dispatch . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6.1. Consuming Dispatch Types . . . . . . . . . . . . . . . . 5 6.1. Consuming Dispatch Types . . . . . . . . . . . . . . . . 5
6.2. New Column in Dispatch Type Registry . . . . . . . . . . 5 6.2. New Column in Dispatch Type Registry . . . . . . . . . . 5
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
The design of Low Power and Lossy Networks (LLNs) is generally The design of Low Power and Lossy Networks (LLNs) is generally
focused on saving energy, which often is a very constrained resource. focused on saving energy, which often is a very constrained resource.
Other constraints, such as memory capacity and duty cycle Other constraints, such as memory capacity and duty cycle
restrictions on LLN devices, usually derive from that primary restrictions on LLN devices, usually derive from that primary
concern. Energy is often available only from primary batteries that concern. Energy is often available only from primary batteries that
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Values of the Dispatch byte defined in [RFC4944] are considered as Values of the Dispatch byte defined in [RFC4944] are considered as
belonging to the Page 0 parsing context, which is the default and belonging to the Page 0 parsing context, which is the default and
does not need to be signaled explicitly at the beginning of a 6LoWPAN does not need to be signaled explicitly at the beginning of a 6LoWPAN
packet. This ensures backward compatibility with existing packet. This ensures backward compatibility with existing
implementations of 6LoWPAN. implementations of 6LoWPAN.
The Dispatch bits defined in Page 0 by [RFC4944] are free to be The Dispatch bits defined in Page 0 by [RFC4944] are free to be
reused in Pages 1 to 15. This specification allocates some values in reused in Pages 1 to 15. This specification allocates some values in
Page 1 in Section 4 and leaves the rest open for future allocations. Page 1 in Section 4 and leaves the rest open for future allocations.
Values opened by this specification in Page 1 to 14 are to be
assigned for new protocols whereas Page 15 is reserved for
experimentations.
Note: This specification does not use the Escape Dispatch, which Note: This specification does not use the Escape Dispatch, which
extends Page 0 to more values, but rather allocates another Dispatch extends Page 0 to more values, but rather allocates another Dispatch
Bit Pattern (1111xxxx) for a new Paging Dispatch, that is present in Bit Pattern (1111xxxx) for a new Paging Dispatch, that is present in
all Pages, including Page 0 and Pages defined in future all Pages, including Page 0 and Pages defined in future
specifications, to indicate the next parsing context represented by specifications, to indicate the next parsing context represented by
its Page Number. The rationale for avoiding that approach is that its Page Number. The rationale for avoiding that approach is that
there can be multiple occurrences of a new header indexed by this there can be multiple occurrences of a new header indexed by this
specification in a single frame and the overhead on an octet each specification in a single frame and the overhead on an octet each
time for the Escape Dispatch would be prohibitive. time for the Escape Dispatch would be prohibitive.
A Page (say Page N) is said to be active once the Page N Paging A Page (say Page N) is said to be active once the Page N Paging
Dispatch is parsed, and as long as no other Paging Dispatch is Dispatch is parsed, and remains active until another Paging Dispatch
parsed. is parsed.
4. Page 1 Paging Dispatch 4. Page 1 Paging Dispatch
This specification defines some special properties for Page 1, This specification defines some special properties for Page 1,
detailed below: detailed below:
The Dispatch bits defined for LOWPAN_IPHC by the Compression The Dispatch bits defined for LOWPAN_IPHC by the Compression
Format for IPv6 Datagrams over IEEE 802.15.4-Based Networks Format for IPv6 Datagrams over IEEE 802.15.4-Based Networks
[RFC6282] are defined with the same values in Page 1 so there is [RFC6282] are defined with the same values in Page 1 so there is
no need to switch context from Page 1 to Page 0 to decode a packet no need to switch context from Page 1 to Page 0 to decode a packet
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if any. if any.
For the same reason, Fragment Headers as defined in [RFC4944] MUST For the same reason, Fragment Headers as defined in [RFC4944] MUST
always be placed in the packet before the first Page 1 Paging always be placed in the packet before the first Page 1 Paging
Dispatch, if any. Dispatch, if any.
The NALP Dispatch Bit Pattern as defined in [RFC4944] is only The NALP Dispatch Bit Pattern as defined in [RFC4944] is only
defined for the first octet in the packet. Switching back to Page defined for the first octet in the packet. Switching back to Page
0 for NALP inside a 6LoWPAN packet does not make sense. 0 for NALP inside a 6LoWPAN packet does not make sense.
parsing context after a context was switched to Page 1, so the As a result, there is no need for restoring the Page 0 parsing
value for the Page 0 Paging Dispatch of 11110000 may not actually context after a context was switched to Page 1, so the value for
occur in those packets that adhere to 6LoWPAN specifications the Page 0 Paging Dispatch of 11110000 may not actually occur in
available at the time of writing this specification. those packets that adhere to 6LoWPAN specifications available at
the time of writing this specification.
5. Security Considerations 5. Security Considerations
The security considerations of [RFC4944] and [RFC6282] apply. The security considerations of [RFC4944] and [RFC6282] apply.
6. IANA Considerations 6. IANA Considerations
6.1. Consuming Dispatch Types 6.1. Consuming Dispatch Types
This document allocates 16 values from the Dispatch type field This document allocates 16 values from the Dispatch type field
registry that was created for [RFC4944]. The allocated values are registry that was created for [RFC4944]. The allocated values are
from 11 110000 through 11 111111 and represent Page Numbers 0 through from 11 110000 through 11 111111 and represent Page Numbers 0 through
15 as discussed in this document. 15 as discussed in this document.
6.2. New Column in Dispatch Type Registry 6.2. New Column in Dispatch Type Registry
This document extends the Dispatch type field registry that was This document extends the Dispatch type field registry that was
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The content of the incumbent registry is assigned to "Page 0". The content of the incumbent registry is assigned to "Page 0".
This document also places in the registry associated to Page 1 the This document also places in the registry associated to Page 1 the
Dispatch type field values that are allocated for LOWPAN_IPHC by Dispatch type field values that are allocated for LOWPAN_IPHC by
[RFC6282]. These values range from 01 100000 through 01 111111 and [RFC6282]. These values range from 01 100000 through 01 111111 and
have the same definition in Page 1 as they do in Page 0; as a result, have the same definition in Page 1 as they do in Page 0; as a result,
the registry entries for Page 0 and Page 1 are an exact overlap in the registry entries for Page 0 and Page 1 are an exact overlap in
this range. this range.
Values ranging from 00000000 to 11101111 in Page 15 (that is all of
Page 15 but the space used for Page switch) is reserved for
experimentations and shall not be assigned.
The resulting registry may be represented as a table as follow The resulting registry may be represented as a table as follow
(partial): (partial):
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pattern | Page | Header Type | defining document | | Pattern | Page | Header Type | defining document |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 0 | NALP | RFC 4944 | | | 0 | NALP | RFC 4944 |
+ 00xxxxxx +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 1..15 | free | N/A | | 00xxxxxx | 1..14 | free | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ N/A |
| | 15 | reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 0 | ESC | RFC 6282 | | | 0 | ESC | RFC 6282 |
+ 01000000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 1..15 | free | N/A | | 01000000 | 1..14 | free | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ N/A |
| | 15 | reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ... ... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 0..1 | LOWPAN_IPHC | RFC 6282 | | | 0..1 | LOWPAN_IPHC | RFC 6282 |
+ 011xxxxx +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | 2..15 | free | | | 011xxxxx | 2..14 | free | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ N/A |
| | 15 | reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ... ... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 1111xxxx | 0..15 | Page switch | This | | 1111xxxx | 0..15 | Page switch | This |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Integrating the new Page column Figure 2: Integrating the new Page column
Future assignments in these registries are to be coordinated via IANA Future assignments in these registries are to be coordinated via IANA
under the policy of "Specification Required" [RFC5226]. It is under the policy of "Specification Required" [RFC5226]. It is
expected that this policy will allow for other (non-IETF) expected that this policy will allow for other (non-IETF)
organizations to more easily obtain assignments. organizations to more easily obtain assignments.
7. Acknowledgments 7. Acknowledgments
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