draft-ietf-6lo-dispatch-iana-registry-00.txt   draft-ietf-6lo-dispatch-iana-registry-01.txt 
6lo S. Chakrabarti 6lo S. Chakrabarti
Internet-Draft Ericsson Internet-Draft Ericsson
Updates: 4944, 6282 (if approved) G. Montenegro Updates: 4944, 6282 (if approved) G. Montenegro
Intended status: Standards Track Microsoft Intended status: Standards Track Microsoft
Expires: August 7, 2016 R. Droms Expires: August 28, 2016 R. Droms
Cisco Cisco
J. Woodyatt J. Woodyatt
Nest Nest
February 4, 2016 February 25, 2016
IANA Registry for 6lowpan ESC Dispatch Code points IANA Registry for 6lowpan ESC Dispatch Code points
draft-ietf-6lo-dispatch-iana-registry-00 draft-ietf-6lo-dispatch-iana-registry-01
Abstract Abstract
RFC4944 defines ESC dispatch type for additional dispatch bytes in RFC4944 defines ESC dispatch type for additional dispatch bytes in
the 6lowpan header. The value of ESC byte has been updated by the 6lowpan header. The value of ESC byte has been updated by
RFC6282. However, the usage of ESC extension byte has not been RFC6282. However, the usage of ESC extension byte has not been
defined in RFC6282 and RFC4944. The purpose of this document is to defined in RFC6282 and RFC4944. The purpose of this document is to
define the ESC extension byte code points and to request define the ESC extension byte code points and to request
corresponding IANA actions. corresponding IANA actions.
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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 August 7, 2016. This Internet-Draft will expire on August 28, 2016.
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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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Usage of ESC dispatch bytes . . . . . . . . . . . . . . . . . . 3 3. Usage of ESC dispatch bytes . . . . . . . . . . . . . . . . . . 3
3.1. Interaction with other RFC4944 implementations . . . . . . 4 3.1. Interaction with other RFC4944 implementations . . . . . . 4
3.2. ESC Extension Bytes Typical Sequence . . . . . . . . . . . 5 3.2. ESC Extension Bytes Typical Sequence . . . . . . . . . . . 5
3.3. Example: ITU-T G.9903 ESC type usage . . . . . . . . . . . 5 3.3. Example: ITU-T G.9903 ESC type usage . . . . . . . . . . . 5
3.4. NALP Usage . . . . . . . . . . . . . . . . . . . . . . . . 6 3.4. NALP and ESC bytes . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
[RFC4944] section 5.1 defines the dispatch header and types. The ESC [RFC4944] section 5.1 defines the dispatch header and types. The ESC
type is defined for using additional dispatch bytes in the 6lowpan type is defined for using additional dispatch bytes in the 6lowpan
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Usage of ESC dispatch bytes 3. Usage of ESC dispatch bytes
RFC 4944 [RFC4944] first introduces this "ESC" dispatch header type RFC 4944 [RFC4944] first introduces this "ESC" dispatch header type
for extension of dispatch bytes. RFC 6282 [RFC6282] subsequently for extension of dispatch bytes. RFC 6282 [RFC6282] subsequently
modified its value to [01 000000]. modified its value to [01 000000].
This document specifies that the first octet following the ESC byte This document specifies that the first octet following the ESC byte
be used for extension type(extended dispatch values). Subsequent be used for extension type (extended dispatch values). Subsequent
octets are left unstructured for the specific use of the extension octets are left unstructured for the specific use of the extension
type: type:
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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 1| ESC | ESC EXT Type | Extended Dispatch Payload |0 1| ESC | ESC EXT Type | Extended Dispatch Payload
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Frame Format with ESC Byte Figure 1: Frame Format with ESC Byte
ESC: The left-most byte is the ESC dispatch type containing '0100000' ESC: The left-most byte is the ESC dispatch type containing '0100000'
ESC Extension Type(EET): It is the first byte following the ESC byte. ESC Extension Type (EET): It is the first byte following the ESC
Extension type defines the payload for the additional dispatch bytes. byte. Extension type defines the payload for the additional dispatch
The values are from 0 to 255. Value 0 and 255 are reserved for bytes. The values are from 0 to 255. Value 0 and 255 are reserved
future use. These values are assigned by IANA. The EET values are for future use. These values are assigned by IANA. The EET values
similar to dispatch values in the 6lowpan header except they are are similar to dispatch values in the 6lowpan header except they are
preceeded by the ESC byte. Thus, ESC extension types and dispatch preceeded by the ESC byte. Thus, ESC extension types and dispatch
values are using orthogonal code spaces. Though not desirable, values are using orthogonal code spaces. Though not desirable,
multiple ESC bytes MAY appear in a 6lowpan header. Section 3.1 multiple ESC bytes MAY appear in a 6lowpan header. For example, it
describes how to handle unknown ESC dispatch type. is possible to form [Mesh-hdr][6lowpan-
IPHC][Payload][ESC][EET][Payload][ESC][EET][Payload] as long as it
follows the same semantics defined in this document and does not
induce fragmentation. Section 3.1 describes how to handle unknown
ESC dispatch type.
Extended Dispatch Payload(EDP): This part of frame format must be Extended Dispatch Payload(EDP): This part of frame format must be
defined by the corresponding extension type. A specification is defined by the corresponding extension type. A specification is
required to define each usage of extension type and its corresponding required to define each usage of extension type and its corresponding
Extension Payload. Extension Payload. For the sake of interoperability, specifications
of extension bytes MUST NOT redefine the existing ESC Extension Type
codes.
Note that section 5.1 in RFC4944 indicates that the Extension Type Section 5.1 in RFC4944 indicates that the Extension Type field may
field may contain additional dispatch values larger than 63 contain additional dispatch values larger than 63, as corrected by
[4944-ERRATA]. Note that the new dispatch type MUST NOT modify the [4944-ERRATA]. For the sake of interoperability, the new dispatch
behavior of existing dispatch types for the sake of interoperability. type (EET) MUST NOT modify the behavior of existing dispatch types
[RFC4944].
3.1. Interaction with other RFC4944 implementations 3.1. Interaction with other RFC4944 implementations
It is expected that RFC4944 existing implementations are not capable It is expected that RFC4944 existing implementations are not capable
of processing ESC extension data bytes as defined in this document. of processing ESC extension data bytes as defined in this document.
However, implementors have to assume that existing implementation However, implementors have to assume that existing implementation
that attempt to process an EET unknown to them will simply drop the that attempt to process an EET unknown to them will simply drop the
packet or ignore the ESC dispatch bytes. packet or ignore the ESC dispatch bytes.
If an implementation following this document, during processing of If an implementation following this document, during processing of
the received packet reaches the ESC byte for which it does not the received packet reaches the ESC byte for which it does not
understand the extension bytes (EET), it MUST drop that packet. understand the extension bytes (EET), it MUST drop that packet.
However, it is important to clarify that a router node SHOULD forward However, it is important to clarify that a router node SHOULD forward
a 6lowpan packet with the EET bytes as long as it does not attempt to a 6lowpan packet with the EET bytes as long as it does not attempt to
process any ESC extension bytes. process any unknown ESC extension bytes.
Sequence Of dispatch bytes and ESC bytes: Multiple ESC extension Sequence Of dispatch bytes and ESC bytes: Multiple ESC extension
bytes may appear in a packet. Could a 6lowpan packet start with a bytes may appear in a packet. The ESC bytes can appear as the first,
ESC dispatch type? In another word, should ESC extension always be last or middle dispatch bytes. However, a packet will get dropped by
preceeded by non-ESC dispatch bytes? any node that does not understand the EET at the beginning of the
packet. The closer to the end of the packet are the EET's, the
gab: I think the answer is no. But per the previous sentence, you higher chance there is that a legacy node will recognize and
have to assume that your packet will get dropped immediately by any successfully process some dispatch type [RFC4944] before the EET and
node that does not understand the EET at the beginning of the packet. then ignore the EET instead of dropping the entire packet.
The closer to the end of the packet are the EET's, the higher chance
there is that a legacy node will recognize and successfully process
some dispatch type before the EET and then ignore the EET instead of
dropping the entire packet. Unless you know for sure that all nodes
in your network understand a given EET (by definition a private and
non-standard deployment), placing it at the beginning is a good way
to guarantee that the packet will get dropped.
3.2. ESC Extension Bytes Typical Sequence 3.2. ESC Extension Bytes Typical Sequence
The following diagram provides an example when ESC extension bytes The following diagram provides an example when ESC extension bytes
might be used: might be used:
A LoWPAN encapsulated HC1 compressed packet: A LoWPAN encapsulated HC1 compressed packet:
+----------+-----------------+---------+-----+-----+--------+ +----------+-----------------+---------+-----+-----+--------+
| Dispatch | LOWPAN_IPHC hdr | Payld |ESC | EET |EPayld | | Dispatch | LOWPAN_IPHC hdr | Payld |ESC | EET |EPayld |
+----------------------------+---------+-----+-----+--------+ +----------------------------+---------+-----+-----+--------+
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The frame format is defined as follows: The frame format is defined as follows:
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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 1| ESC | Command ID | Command Payload |0 1| ESC | Command ID | Command Payload
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: G.9903 Frame Format with ESC Byte Figure 3: G.9903 Frame Format with ESC Byte
3.4. NALP Usage 3.4. NALP and ESC bytes
There were several comments on 00 draft -- that this draft should
provide guidance on NALP usage as there was no clear distinction
between ITU-T command mode usage and NALP usage. In order to avaoid
such confusion, a NALP usage guidance should be provided. This is a
space holder section in order to decide whether NALP usage indeed
should belong here.
gab: I don't think we need to say anything beyond what we already say According to RFC4944 [RFC4944] section 5.1, NALP dispatch bytes are
in 4944: it is not a 6lowpan frame. This was done recognizing that used for non-6lowpan packets. Since ESC bytes are part of 6lowpan
some SDO's would also define their own frame structure, in dispatch types (extended), they are orthogonal to NALP bytes.
particular, Zigbee. There was some effort to agree with them on some
way for our definitions to not collide. So prescribing usage of
NALP, beyond saying it is not 6lowpan nor the subject of any IETF
document, would defeat the purpose.
4. IANA Considerations 4. IANA Considerations
This document requests IANA to register the 'ESC Extension Type' This document requests IANA to register the 'ESC Extension Type'
values as per the policy 'Specification Required'[RFC5226] as values as per the policy 'Specification Required'[RFC5226] as
specified in this document which follows the same policy as in the specified in this document which follows the same policy as in the
IANA section of [RFC4944]. For each Extension Type(except the IANA section of [RFC4944]. For each Extension Type (except the
Reserved values)the specification MUST define corresponding Extended Reserved values) the specification MUST define corresponding Extended
Dispatch Payload frame bytes for the receiver implementation to read Dispatch Payload frame bytes for the receiver implementation to read
the ESC bytes with interoperability. the ESC bytes with interoperability.
The initial values for the 'ESC Extension Type' fields are: The initial values for the 'ESC Extension Type' fields are:
+-------+---------------------------------+---------------+ +-------+---------------------------------+---------------+
| Value | Description | Reference | | Value | Description | Reference |
+-------+---------------------------------+---------------+ +-------+---------------------------------+---------------+
| 0 | Reserved for future use | This document | | 0 | Reserved for future use | This document |
| | | | | | | |
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