Internet DRAFT - draft-richardson-6lo-ra-in-ie
draft-richardson-6lo-ra-in-ie
6lo Working Group M. Richardson
Internet-Draft Sandelman Software Works
Intended status: Informational October 18, 2016
Expires: April 21, 2017
802.15.4 Informational Element encapsulation of ICMPv6 Router
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draft-richardson-6lo-ra-in-ie-00
Abstract
In TSCH mode of 802.15.4, as described by [I-D.ietf-6tisch-minimal],
opportunities for broadcasts are limited to specific times and
specific channels. An enhanced beacon must be broadcast periodically
by every router to keep all nodes in sync. This document provides a
mechanism by which other small ICMPv6 packets, such as Router
Advertisements may be carried within the Enhanced Beacon, providing
standard IPv6 router/host protocol.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 21, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Layer-2 Synchronization . . . . . . . . . . . . . . . . . 2
1.3. Layer-3 synchronization IPv6 Router solicitations and
advertisements . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Definition . . . . . . . . . . . . . . . . . . . . . 3
2.1. Protocol Example . . . . . . . . . . . . . . . . . . . . 4
3. Security Considerations . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. appendix . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[I-D.ietf-6tisch-architecture] describes the use of the time-slotted
channel hopping (TSCH) mode of [ieee802154]. As further details in
[I-D.ietf-6tisch-minimal], an Extended Beacon is transmitted during a
slot designated a broadcast slot.
EDNOTE: Explain why broadcasts are rare, and why we need them. What
the Enhanced Beacon is, and what Information Elements are, and how
the IETF has a subtype for that area. Explain what kind of things
could be placed in Information Elements, how big they could be, and
how they could be compressed.
1.1. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119
[RFC2119] and indicate requirement levels for compliant STuPiD
implementations.
1.2. Layer-2 Synchronization
As explained in section 6 of [I-D.ietf-6tisch-minimal], the Extended
Beacon has a number of purposes: synchronization of ASN and Join
Metric, timeslot template identifier, the channel hopping sequence
identifier, TSCH SlotFrame and Link IE.
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The Extended Beacon is used by operating nodes to correct drift to
their clock, by nodes on medium length sleeps to resynchronize their
ASN, by nodes that have slept through a network rekey to rediscover
the network, and by new Joining Nodes (pledges) to learn about the
existance of the network.
There are a limited number of timeslots designated as a broadcast
slot by each router. These slots are rare, and with 10ms slots, with
a slot-frame length of 100, there may be only 1 slot/s for the
beacon.
1.3. Layer-3 synchronization IPv6 Router solicitations and
advertisements
At layer 3, [RFC2461] defines a mechanism by which nodes learn about
routers by listening for multicasted Router Advertisements (RA). If
no RA is heard within a set time, then a Router Solicitation (RS) may
be multicast, to which an RA will be received, usually unicast.
Although [RFC6775] reduces the amount of multicast necessary to do
address resolution via Neighbor Solicitation messages, it still
requires multicast of either RAs or RS. This is an expensive
operation for two reasons: there are few multicast timeslots for
unsolicited RAs; if a pledge node does not hear an RA, and decides to
send a RS (consuming a broadcast aloha slot with unencrypted
traffic), many unicast RS may be sent in response.
This is a particularly acute issue for the join process for the
following reasons:
1. use of a multicast slot by even a non-malicious unauthenticated
node for a Router Solicitation may overwhelm that time slot.
2. it may require many seconds of on-time before a new pledge hears
a Router Soliciation that it can use.
3. a new pledge may listen to many Enhanced Beacons before it can
pick an appropriate network and/or closest Join Assistant to
attach to. If it must listen for a RS as well as find the
Enhanced Beacon, then the process may take a very long time.
2. Protocol Definition
[I-D.kivinen-802-15-ie] creates a registry for new IETF IE subtypes.
This document allocates a new subtype TBD-XXX.
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The base IE subtype structure is as follows. As explained in
[I-D.kivinen-802-15-ie] the length of the Sub-Type Content can be
calculated.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TBD-XXX | 6LoRH encoded structure |
+-+-+-+-+-+-+-+-+ |
~ Sub-Type Content ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Inside the Sub-Type content should be placed compressed packets
according to [RFC6282] (as updated by
[I-D.ietf-6lo-dispatch-iana-registry].
2.1. Protocol Example
Typically a Router Advertisement will be placed inside the Sub-Type.
The entire structure typically looks like:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver 6 | TC = 0 | Flow Label = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | NH = 58 | Hop Lmt = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source Address +
| fe80::LL |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination Address +
| fe02::1 |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 134 | Code = 0 | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HL = 0 |0|0| Reserved | Router lifetime = 9000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reachable Time = 0 XXX |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retrans Timer = 0 XXX |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 1 | Len = 10 | EUI-64 of router |
+-+-+-+-+-+-+-+-+-+-+-+---------+ +
| EUI-64 of router |
+ +---------------+---------------+
| EUI-64 of router | Type = TBD-YYY| Len = 18 |
+-------------------------------+-------------------------------+
| DODAGID |
+ |
| |
+ |
| |
+ |
| |
+---------------------------------------------------------------+
When compressed by [RFC6282], this becomes:
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+---------------------------------------------------------------+
| 0 | 1 | 1 |TF= 11 |NH |HLIM=01|CID|SAC| SAM | M |DAC| DAM | 0
+ | | | | 0 | | 0 | 0 | 0 1 + 1 + 0 + 1 1 +
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| NH = 0x58 | dstXX = 0x01 | 4
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 134 | Code = 0 | Checksum | 8
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HL = 0 |0|0| Reserved | Router lifetime = 9000 | 12
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reachable Time = 0 XXX | 16
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Retrans Timer = 0 XXX | 20
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 1 | Len = 10 | EUI-64 of router | 24
+-+-+-+-+-+-+-+-+-+-+-+---------+ +
| EUI-64 of router | 28
+ +---------------+---------------+
| EUI-64 of router | Type = TBD-YYY| Len = 18 | 32
+-------------------------------+-------------------------------+
| DODAGID | 36
+ |
| | 40
+ |
| | 44
+ |
| | 48
+---------------------------------------------------------------+
The total number of bytes needed is 56 bytes.
3. Security Considerations
TBD.
4. IANA Considerations
Allocate a new number TBD-XXX from Registry IETF IE Sub-type ID.
This entry should be called 6LoRH-in-IE.
Allocate a new number TBD-YYY from Neighbor Discovery Option Types
(RFC2461) with the name "Constrained Network Identification".
5. References
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5.1. Normative References
[I-D.ietf-6lo-dispatch-iana-registry]
Chakrabarti, S., Montenegro, G., Droms, R., and j.
woodyatt, "6lowpan ESC Dispatch Code Points and
Guidelines", draft-ietf-6lo-dispatch-iana-registry-05
(work in progress), September 2016.
[I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work
in progress), June 2016.
[I-D.ietf-6tisch-minimal]
Vilajosana, X. and K. Pister, "Minimal 6TiSCH
Configuration", draft-ietf-6tisch-minimal-16 (work in
progress), June 2016.
[I-D.kivinen-802-15-ie]
Kivinen, T. and P. Kinney, "IEEE 802.15.4 Information
Element for IETF", draft-kivinen-802-15-ie-03 (work in
progress), October 2016.
[ieee802154]
IEEE Standard, ., "802.15.4-2015 - IEEE Standard for Low-
Rate Wireless Personal Area Networks (WPANs)", 2015,
<http://standards.ieee.org/findstds/
standard/802.15.4-2015.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2461] Narten, T., Nordmark, E., and W. Simpson, "Neighbor
Discovery for IP Version 6 (IPv6)", RFC 2461,
DOI 10.17487/RFC2461, December 1998,
<http://www.rfc-editor.org/info/rfc2461>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<http://www.rfc-editor.org/info/rfc6282>.
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[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<http://www.rfc-editor.org/info/rfc6775>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<http://www.rfc-editor.org/info/rfc7228>.
5.2. Informative References
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <http://www.rfc-editor.org/info/rfc4191>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", RFC 4443,
DOI 10.17487/RFC4443, March 2006,
<http://www.rfc-editor.org/info/rfc4443>.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<http://www.rfc-editor.org/info/rfc4655>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.
[RFC7554] Watteyne, T., Ed., Palattella, M., and L. Grieco, "Using
IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) in the
Internet of Things (IoT): Problem Statement", RFC 7554,
DOI 10.17487/RFC7554, May 2015,
<http://www.rfc-editor.org/info/rfc7554>.
Appendix A. appendix
insert appendix here
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Author's Address
Michael Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
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