One document matched: draft-ietf-6lo-6lobac-06.xml
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<rfc category="std" ipr="trust200902" docName="draft-ietf-6lo-6lobac-06">
<front>
<title abbrev=" IPv6 over MS/TP "> Transmission of IPv6 over MS/TP Networks </title>
<author fullname="Kerry Lynn" initials="K.E." surname="Lynn" role="editor">
<organization> Verizon Labs </organization>
<address>
<postal>
<street> 50 Sylvan Rd </street>
<city> Waltham </city>
<region> MA </region>
<code> 02451 </code>
<country> USA </country>
</postal>
<phone> +1 781 296 9722 </phone>
<email> kerlyn@ieee.org </email>
</address>
</author>
<author fullname="Jerry Martocci" initials="J.P." surname="Martocci">
<organization abbrev="Johnson Controls"> Johnson Controls, Inc. </organization>
<address>
<postal>
<street> 507 E. Michigan St </street>
<city> Milwaukee </city>
<region> WI </region>
<code> 53202 </code>
<country> USA </country>
</postal>
<email> jpmartocci@sbcglobal.net </email>
</address>
</author>
<author fullname="Carl Neilson" initials="C." surname="Neilson">
<organization abbrev="Delta Controls"> Delta Controls, Inc. </organization>
<address>
<postal>
<street> 17850 56th Ave </street>
<city> Surrey </city>
<region> BC </region>
<code> V3S 1C7 </code>
<country> Canada </country>
</postal>
<phone> +1 604 575 5913 </phone>
<email> cneilson@deltacontrols.com </email>
</address>
</author>
<author fullname="Stuart Donaldson" initials="S." surname="Donaldson">
<organization abbrev="Honeywell"> Honeywell Automation & Control Solutions </organization>
<address>
<postal>
<street> 6670 185th Ave NE </street>
<city> Redmond </city>
<region> WA </region>
<code> 98052 </code>
<country> USA </country>
</postal>
<email> stuart.donaldson@honeywell.com </email>
</address>
</author>
<date day="31" month="October" year="2016"/>
<area> Internet </area>
<workgroup> 6Lo Working Group </workgroup>
<abstract>
<t>
Master-Slave/Token-Passing (MS/TP) is a medium access control method
for the RS-485 physical layer, which is used extensively in building
automation networks. This specification defines the frame format for
transmission of IPv6 packets and the method of forming link-local and
statelessly autoconfigured IPv6 addresses on MS/TP networks.
</t>
</abstract>
</front>
<middle>
<!-- section anchor="sec-1" title="Introduction" -->
<section title="Introduction">
<t>
Master-Slave/Token-Passing (MS/TP) is a medium access control (MAC)
protocol for the RS-485 <xref target="TIA-485-A"/> physical layer, which is used
extensively in building automation networks. This specification
defines the frame format for transmission of IPv6 <xref target="RFC2460"/> packets
and the method of forming link-local and statelessly autoconfigured
IPv6 addresses on MS/TP networks. The general approach is to adapt
elements of the 6LoWPAN specifications <xref target="RFC4944"/>, <xref target="RFC6282"/>, and
<xref target="RFC6775"/>, where noted, to constrained wired networks.
</t><t>
An MS/TP device is typically based on a low-cost microcontroller with
limited processing power and memory. Together with low data rates
and a small MAC address space, these constraints are similar to those
faced in 6LoWPAN networks and suggest some elements of that solution
might be leveraged. MS/TP differs significantly from 6LoWPAN in at
least three respects: a) MS/TP devices typically have a continuous
source of power, b) all MS/TP devices on a segment can communicate
directly so there are no hidden node or mesh routing issues, and c)
recent changes to MS/TP provide support for larger payloads,
eliminating the need for fragmentation and reassembly below IPv6.
</t><t>
The following sections provide a brief overview of MS/TP, then
describe how to form IPv6 addresses and encapsulate IPv6 packets in
MS/TP frames. This document also specifies a header compression
mechanism, based on <xref target="RFC6282"/>, that is REQUIRED in order to
reduce latency and make IPv6 practical on MS/TP networks.
</t>
<!-- section anchor="sec-1.1" title="Requirements Language" -->
<section title="Requirements Language">
<t>
The key words "MUST", "MUST NOT",
"REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be
interpreted as described in <xref target="RFC2119"/>.
</t>
</section>
<!-- section anchor="sec-1.2" title="Abbreviations Used" -->
<section title="Abbreviations Used">
<figure>
<artwork>
ASHRAE: American Society of Heating, Refrigerating, and Air-
Conditioning Engineers (http://www.ashrae.org)
BACnet: An ISO/ANSI/ASHRAE Standard Data Communication Protocol
for Building Automation and Control Networks
CRC: Cyclic Redundancy Check
MAC: Medium Access Control
MSDU: MAC Service Data Unit (MAC client data)
MTU: Maximum Transmission Unit
UART: Universal Asynchronous Transmitter/Receiver
</artwork>
</figure>
</section>
<section anchor="sec-1.3" title="MS/TP Overview" >
<!-- section title="MS/TP Overview" -->
<t>
This section provides a brief overview of MS/TP, which is specified
in ANSI/ASHRAE 135-2012 (BACnet) Clause 9 <xref target="Clause9"/> and included
herein by reference. BACnet <xref target="Clause9"/> also covers physical layer
deployment options.
</t><t>
MS/TP is designed to enable multidrop networks over shielded twisted
pair wiring. It can support network segments up to 1000 meters in
length at a data rate of 115,200 bit/s, or segments up to 1200 meters
in length at lower bit rates. An MS/TP link requires only a UART,
an RS-485 <xref target="TIA-485-A"/> transceiver with a driver that can be disabled,
and a 5 ms resolution timer. These features make MS/TP a cost-
effective field bus for the most numerous and least expensive devices
in a building automation network.
</t><t>
The differential signaling used by <xref target="TIA-485-A"/> requires a contention-
free MAC. MS/TP uses a token to control access to a multidrop bus.
A master node may initiate the transmission of a data frame when it
holds the token. After sending at most a configured maximum number
of data frames, a master node passes the token to the next master
node (as determined by MAC address). If present on the link, legacy
MS/TP implementations (including all slave nodes) ignore the frame
format defined in this specification.
</t><t>
BACnet Addendum 135-2012an [Addendum_an] defines a range of Frame
Type values to designate frames that contain larger data and data CRC
fields, encoded using Consistent Overhead Byte Stuffing [COBS] (see
Appendix B). The purpose of COBS encoding is to eliminate preamble
sequences from the Encoded Data and Encoded CRC-32K fields. The
maximum length of an MSDU as defined by this specification is 1500
octets (before encoding). The Encoded Data is covered by a 32-bit
CRC [CRC32K] (see Appendix C). The CRC-32K is then COBS encoded.
</t><t>
MS/TP COBS-encoded frames have the following format:
</t>
<figure title="Figure 1: MS/TP COBS-Encoded Frame Format" align="center">
<artwork>
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x55 | 0xFF | Frame Type | DA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SA | Length (MS octet first) | Header CRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Encoded Data (2 - 1506 octets) .
. .
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Encoded CRC-32K (5 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| | optional 0xFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</artwork>
</figure>
<t>
MS/TP COBS-encoded frame fields have the following descriptions:
</t>
<figure>
<artwork>
Preamble two octet preamble: 0x55, 0xFF
Frame Type one octet
Destination Address one octet address
Source Address one octet address
Length two octets, most significant octet first
Header CRC one octet
Encoded Data 2 - 1506 octets (see Appendix B)
Encoded CRC-32K five octets (see Appendix C)
(pad) (optional) at most one octet of trailer: 0xFF
</artwork>
</figure>
<figure>
<artwork>
The Frame Type is used to distinguish between different types of MAC
frames. The types relevant to this specification (in decimal) are:
0 Token
1 Poll For Master
2 Reply To Poll For Master
...
34 IPv6 over MS/TP (LoBAC) Encapsulation
</artwork>
</figure>
<t>
Frame Types 8 - 31 and 35 - 127 are reserved for assignment by
ASHRAE. Frame Types 32 - 127 designate COBS-encoded frames and MUST
convey Encoded Data and Encoded CRC-32K fields. All master nodes
MUST understand Token, Poll For Master, and Reply to Poll For Master
control frames. See <xref target="sec-2"/> for additional details.
</t><t>
The Destination and Source Addresses are each one octet in length.
See <xref target="sec-3"/> for additional details.
</t><t>
For COBS-encoded frames, the Length field indicates the size of the
<xref target="COBS"/> Encoded Data field in octets, plus three. (This adjustment is
required in order for legacy MS/TP devices to ignore COBS-encoded
frames.) See <xref target="sec-4"/> and Appendices for additional details.
</t><t>
The Header CRC field covers the Frame Type, Destination Address,
Source Address, and Length fields. The Header CRC generation and
check procedures are specified in BACnet <xref target="Clause9"/>.
</t><t>
Use of the optional 0xFF trailer octet is discussed in BACnet <xref target="Clause9"/>.
</t>
</section>
<!-- section anchor="sec-1.4" title="Goals and Constraints" -->
<section title="Goals and Constraints">
<t>
The primary goal of this specification is to enable IPv6 directly on
wired end devices in building automation and control networks by
leveraging existing standards to the greatest extent possible. A
secondary goal is to co-exist with legacy MS/TP implementations.
Only the minimum changes necessary to support IPv6 over MS/TP were
specified in BACnet <xref target="Addendum_an"/> (see <xref target="sec-1.3"/>).
</t><t>
In order to co-exist with legacy devices, no changes are permitted to
the MS/TP addressing modes, frame header format, control frames, or
Master Node state machine as specified in BACnet <xref target="Clause9"/>.
</t>
</section>
</section>
<section anchor="sec-2" title="MS/TP Mode for IPv6">
<!-- section title="MS/TP Mode for IP" -->
<t>
ASHRAE has assigned an MS/TP Frame Type value of 34 to indicate IPv6
over MS/TP (LoBAC) Encapsulation. This falls within the range of
values that designate COBS-encoded data frames.
</t><t>
All MS/TP master nodes (including those that support IPv6) MUST
implement the Master Node state machine specified in BACnet <xref target="Clause9"/>
and handle Token, Poll For Master, and Reply to Poll For Master
control frames. MS/TP master nodes that support IPv6 MUST also
implement the Receive Frame state machine specified in <xref target="Clause9"/> as
extended by BACnet <xref target="Addendum_an"/>.
</t><t>
All MS/TP nodes that support IPv6 MUST support a data rate of 115,200
bit/s and MAY optionally support lower data rates as defined in
BACnet <xref target="Clause9"/>.
</t>
</section>
<section anchor="sec-3" title="Addressing Modes">
<!-- section title="Addressing Modes" -->
<t>
MS/TP node (MAC) addresses are one octet in length. The method of
assigning MAC addresses is outside the scope of this specification.
However, each MS/TP node on the link MUST have a unique address in
order to ensure correct MAC operation.
</t><t>
BACnet <xref target="Clause9"/> specifies that addresses 0 through 127 are valid for
master nodes. The method specified in <xref target="sec-6"/> for creating a MAC-
layer-derived Interface Identifier (IID) ensures that an IID of all
zeros can never result.
</t><t>
A Destination Address of 255 (all nodes) indicates a MAC-layer
broadcast. MS/TP does not support multicast, therefore all IPv6
multicast packets MUST be broadcast at the MAC layer and filtered
at the IPv6 layer. A Source Address of 255 MUST NOT be used.
</t><t>
Hosts learn IPv6 prefixes via router advertisements according to
<xref target="RFC4861"/>.
</t>
</section>
<section anchor="sec-4" title="Maximum Transmission Unit (MTU)">
<!--section title="Maximum Transmission Unit (MTU)"-->
<t>
BACnet <xref target="Addendum_an"/> supports MSDUs up to 2032 octets in length.
This specification defines an MSDU length of at least 1280 octets and
at most 1500 octets (before encoding). This is sufficient to convey
the minimum MTU required by IPv6 <xref target="RFC2460"/> without the need for link-
layer fragmentation and reassembly. Support for an MSDU length of
1500 octets is RECOMMENDED.
</t>
</section>
<section anchor="sec-5" title="LoBAC Adaptation Layer">
<!-- section title="LoBAC Adaptation Layer" -->
<t>
The relatively low data rates of MS/TP dictate header compression as
a means to reduce latency. This section specifies an adaptation
layer to support compressed IPv6 headers as specified in <xref target="sec-10"/>.
IPv6 header compression MUST be implemented on all nodes.
</t><t>
Implementations MAY also support Generic Header Compression (GHC)
<xref target="RFC7400"/> for transport layer headers. A node implementing <xref target="RFC7400"/>
MUST probe its peers for GHC support before applying GHC.
</t><t>
The encapsulation format defined in this section (subsequently
referred to as the "LoBAC" encapsulation) comprises the MSDU of an
IPv6 over MS/TP frame. The LoBAC payload (i.e., an IPv6 packet)
follows an encapsulation header stack. LoBAC is a subset of the
LoWPAN encapsulation defined in <xref target="RFC4944"/> and extended by <xref target="RFC6282"/>,
therefore the use of "LOWPAN" in literals below is intentional. The
primary difference between LoWPAN and LoBAC is omission of the Mesh,
Broadcast, Fragmentation, and LOWPAN_HC1 headers.
</t><t>
All LoBAC encapsulated datagrams transmitted over MS/TP are prefixed
by an encapsulation header stack consisting of a Dispatch value
followed by zero or more header fields. The only sequence currently
defined for LoBAC is the LOWPAN_IPHC header followed by payload, as
shown below:
</t>
<figure title="Figure 2: A LoBAC Encapsulated LOWPAN_IPHC Compressed IPv6 Datagram" align="center">
<artwork>
+---------------+---------------+------...-----+
| IPHC Dispatch | IPHC Header | Payload |
+---------------+---------------+------...-----+
</artwork>
</figure>
<t>
The Dispatch value may be treated as an unstructured namespace. Only
a single pattern is used to represent current LoBAC functionality.
</t>
<figure title="Figure 3: LoBAC Dispatch Value Bit Pattern" align="center">
<artwork>
Pattern Header Type
+------------+-----------------------------------------------------+
| 01 1xxxxx | LOWPAN_IPHC - LOWPAN_IPHC compressed IPv6 [RFC6282] |
+------------+-----------------------------------------------------+
</artwork>
</figure>
<t>
Other IANA-assigned 6LoWPAN Dispatch values do not apply to 6LoBAC
unless otherwise specified.
</t>
</section>
<section anchor="sec-6" title="Stateless Address Autoconfiguration">
<!-- section title="Stateless Address Autoconfiguration" -->
<t>
This section defines how to obtain an IPv6 Interface Identifier. The
general procedure for creating a MAC-address-derived IID is described
in <xref target="RFC4291"/> Appendix A, "Creating Modified EUI-64 Format
Interface Identifiers", as updated by <xref target="RFC7136"/>.
</t><t>
The IID SHOULD NOT embed an <xref target="EUI-64"/> or any other globally
unique hardware identifier assigned to a device (see <xref target="sec-12"/>).
</t><t>
The Interface Identifier for link-local addresses SHOULD be formed by
concatenating a node's' 8-bit MS/TP MAC address to the seven octets
0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00. For example, an MS/TP MAC
address of hexadecimal value 0x4F results in the following IID:
</t>
<figure align="center">
<artwork>
|0 1|1 3|3 4|4 6|
|0 5|6 1|2 7|8 3|
+----------------+----------------+----------------+----------------+
|0000000000000000|0000000011111111|1111111000000000|0000000001001111|
+----------------+----------------+----------------+----------------+
</artwork>
</figure>
<t>
This is the RECOMMENDED method of forming an IID for use in link-local
addresses, as it affords the most efficient header compression provided
by the LOWPAN_IPHC <xref target="RFC6282"/> format specified in <xref target="sec-10"/>.
</t><t>
A 64-bit random IID is RECOMMENDED for each globally scoped address
and SHOULD be locally generated according to one of the methods cited
in <xref target="sec-12"/>. A node that generates a 64-bit random IID MUST
register it with its local router(s) by sending a Neighbor
Solicitation (NS) message with the Address Registration Option (ARO)
and process Neighbor Advertisements (NA) according to <xref target="RFC6775"/>.
</t><t>
An IPv6 address prefix used for stateless autoconfiguration <xref target="RFC4862"/> of an MS/TP
interface MUST have a length of 64 bits.
</t>
</section>
<!-- section anchor="sec-7" title="IPv6 Link Local Address" -->
<section title="IPv6 Link Local Address">
<t>
The IPv6 link-local address <xref target="RFC4291"/> for an MS/TP interface is
formed by appending the Interface Identifier, as defined above, to
the prefix FE80::/64.
</t>
<figure align="center">
<artwork>
10 bits 54 bits 64 bits
+----------+-----------------------+----------------------------+
|1111111010| (zeros) | Interface Identifier |
+----------+-----------------------+----------------------------+
</artwork>
</figure>
</section>
<!-- section anchor="sec-8" title="Unicast Address Mapping" -->
<section title="Unicast Address Mapping">
<t>
The address resolution procedure for mapping IPv6 non-multicast
addresses into MS/TP MAC-layer addresses follows the general
description in Section 7.2 of <xref target="RFC4861"/>, unless otherwise specified.
</t><t>
The Source/Target Link-layer Address option has the following form
when the addresses are 8-bit MS/TP MAC-layer (node) addresses.
</t>
<figure align="center">
<artwork>
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | MS/TP Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Padding (all zeros) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</artwork>
</figure>
<figure>
<artwork>
Option fields:
Type:
1: for Source Link-layer address.
2: for Target Link-layer address.
Length: This is the length of this option (including the type and
length fields) in units of 8 octets. The value of this field is 1
for 8-bit MS/TP MAC addresses.
MS/TP Address: The 8-bit address in canonical bit order [RFC2469].
This is the unicast address the interface currently responds to.
</artwork>
</figure>
</section>
<!-- section anchor="sec-9" title="Multicast Address Mapping" -->
<section title="Multicast Address Mapping">
<t>
All IPv6 multicast packets MUST be sent to MS/TP Destination
Address 255 (broadcast) and filtered at the IPv6 layer. When
represented as a 16-bit address in a compressed header (see
<xref target="sec-10"/>), it MUST be formed by padding on the left with a zero:
</t>
<figure align="center">
<artwork>
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0xFF |
+-+-+-+-+-+-+-+-+---------------+
</artwork>
</figure>
</section>
<section anchor="sec-10" title="Header Compression">
<!-- section title="Header Compression" -->
<t>
LoBAC uses LOWPAN_IPHC IPv6 compression, which is specified in
<xref target="RFC6282"/> and included herein by
reference. This section will simply identify substitutions that
should be made when interpreting the text of <xref target="RFC6282"/>.
</t><t>
In general the following substitutions should be made:
</t><t>
<list style="hanging">
<t hangText=" -">Replace instances of "6LoWPAN" with "MS/TP network"</t>
<t hangText=" -">Replace instances of "IEEE 802.15.4 address" with "MS/TP address"</t>
</list>
</t><t>
When a 16-bit address is called for (i.e., an IEEE 802.15.4 "short
address") it MUST be formed by padding the MS/TP address to the
left with a zero:
</t>
<figure align="center">
<artwork>
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | MS/TP address |
+-+-+-+-+-+-+-+-+---------------+
</artwork>
</figure>
<t>
If LOWPAN_IPHC compression <xref target="RFC6282"/> is used with context, the
router(s) directly attached to the MS/TP segment MUST disseminate the
6LoWPAN Context Option (6CO) according to <xref target="RFC6775"/>, Section 7.2.
</t>
</section>
<!-- section anchor="IANA" title="IANA Considerations" -->
<section title="IANA Considerations">
<t>
This document uses values previously reserved by <xref target="RFC4944"/> and
<xref target="RFC6282"/> and makes no further requests of IANA.
</t><t>
Note to RFC Editor: this section may be removed upon publication.
</t>
</section>
<section anchor="sec-12" title="Security Considerations" >
<!-- section title="Security Considerations" -->
<t>
Globally scoped addresses that contain IIDs generated using MS/TP
node addresses may expose a network to address scanning attacks. For
this reason, it is RECOMMENDED that a different (but stable) IID be
generated for each globally scoped address in use according to, for
example, <xref target="RFC3315"/>, <xref target="RFC3972"/>,
<xref target="RFC4941"/>, <xref target="RFC5535"/>, or <xref target="RFC7217"/>.
</t><t>
MS/TP networks are by definition wired and not susceptible to
casual eavesdropping. By the same token, MS/TP nodes are
stationary and correlation of activities or location tracking
of individuals is unlikely. See <xref target="I-D.ietf-6lo-privacy-considerations"/> for
a full discussion of mitigation of the threats posed to constrained nodes.
</t>
</section>
<!-- section anchor="Acknowledgments" title="Acknowledgments" -->
<section title="Acknowledgments">
<t>
We are grateful to the authors of <xref target="RFC4944"/> and members of the IETF
6LoWPAN working group; this document borrows liberally from their
work. Ralph Droms and Brian Haberman provided indispensable guidance
and support from the outset. Peter van der Stok, James Woodyatt, and
Carsten Bormann provided detailed reviews. Stuart Cheshire invented
the very clever COBS encoding. Michael Osborne made the critical
observation that separately encoding the data and CRC32K fields would
allow the CRC to be calculated on-the-fly. Alexandru Petrescu, Brian
Frank, Geoff Mulligan, and Don Sturek offered valuable comments.
</t>
</section>
</middle>
<back>
<references title="Normative References">
&RFC2119;
&RFC2460;
&RFC4291;
&RFC4861;
&RFC4862;
&RFC4944;
&RFC6282;
&RFC6775;
&RFC7136;
&RFC7400;
&RFC3315;
&RFC3972;
&RFC4941;
&RFC5535;
&RFC7217;
<reference anchor="Clause9">
<front>
<title>
BACnet - A Data Communication Protocol for Building Automation and Control Networks
</title>
<author>
<organization>American Society of Heating, Refrigerating, and Air-Conditioning Engineers</organization>
</author>
<date month="March" year="2013"/>
</front>
<seriesInfo name="ANSI/ASHRAE" value="135-2012 (Clause 9)"/>
</reference>
<reference anchor="Addendum_an" target="https://www.ashrae.org/File%20Library/docLib/StdsAddenda/07-31-2014_135_2012_an_at_au_av_aw_ax_az_Final.pdf">
<front>
<title>
ANSI/ASHRAE Addenda an, at, au, av, aw, ax, and az to ANSI/ASHRAE Standard 135-2012, BACnet - A Data Communication Protocol for Building Automation and Control Networks
</title>
<author>
<organization>ASHRAE</organization>
</author>
<date month="July" year="2014"/>
</front>
</reference>
</references>
<?rfc compact="no" ?>
<references title="Informative References">
&I-D.ietf-6lo-privacy-considerations;
<reference anchor="COBS" target="http://www.stuartcheshire.org/papers/COBSforToN.pdf">
<front>
<title>Consistent Overhead Byte Stuffing</title>
<author initials="S." surname="Cheshire" fullname="Stuart Cheshire"/>
<author initials="M." surname="Baker" fullname="Mary Baker"/>
<date year="1999" month="April"/>
</front>
<seriesInfo name="IEEE/ACM TRANSACTIONS ON NETWORKING, VOL.7, NO.2" value=""/>
</reference>
<reference anchor="CRC32K" target="http://www.ece.cmu.edu/~koopman/networks/dsn02/dsn02_koopman.pdf">
<front>
<title>32-Bit Cyclic Redundancy Codes for Internet Applications</title>
<author initials="P." surname="Koopman" fullname="Philip Koopman"/>
<date year="2002" month="June"/>
</front>
<seriesInfo name="IEEE/IFIP International Conference on Dependable Systems and Networks (DSN 2002)" value=""/>
</reference>
<reference anchor="EUI-64" target="http://standards.ieee.org/regauth/oui/tutorials/EUI64.html">
<front>
<title>
Guidelines for 64-bit Global Identifier (EUI-64) Registration Authority
</title>
<author>
<organization>IEEE</organization>
</author>
<date month="March" year="1997"/>
</front>
</reference>
<!-- Patterned after http://xml.resource.org/public/rfc/bibxml2/_reference.IEEE.802-3.1998.xml -->
<reference anchor="IEEE.802.3" target="http://standards.ieee.org/getieee802/802.3.html">
<front>
<title>
Information technology - Telecommunications and information exchange between systems -
Local and metropolitan area networks - Specific requirements -
Part 3: Carrier Sense Multiple Access with Collision Detection (CMSA/CD) Access Method and Physical Layer Specifications
</title>
<author/>
<date year="2012" month="December"/>
</front>
<seriesInfo name="IEEE" value="Std 802.3-2012"/>
</reference>
&RFC2469;
<reference anchor="TIA-485-A">
<front>
<title>
TIA-485-A, Electrical Characteristics of Generators and Receivers for Use in Balanced Digital Multipoint Systems (ANSI/TIA/EIA-485-A-98) (R2003)
</title>
<author>
<organization>Telecommunications Industry Association</organization>
</author>
<date month="March" year="2003"/>
</front>
</reference>
</references>
<section anchor="app-a" title="Abstract MAC Interface">
<t>
This Appendix is informative and not part of the standard.
</t><t>
BACnet <xref target="Clause9"/> provides support for MAC-layer clients through its
SendFrame and ReceivedDataNoReply procedures. However, it does not
define a network-protocol independent abstract interface for the MAC.
This is provided below as an aid to implementation.
</t>
<section title="MA-DATA.request">
<section title="Function">
<t>
This primitive defines the transfer of data from a MAC client entity
to a single peer entity or multiple peer entities in the case of a
broadcast address.
</t>
</section>
<section title="Semantics of the Service Primitive">
<figure>
<artwork>
The semantics of the primitive are as follows:
MA-DATA.request (
destination_address,
source_address,
data,
type
)
</artwork>
</figure>
<t>
The 'destination_address' parameter may specify either an individual
or a broadcast MAC entity address. It must contain sufficient
information to create the Destination Address field (see <xref target="sec-1.3"/>) that is
prepended to the frame by the local MAC sublayer entity. The
'source_address' parameter, if present, must specify an individual
MAC address. If the source_address parameter is omitted, the local
MAC sublayer entity will insert a value associated with that entity.
</t><t>
The 'data' parameter specifies the MAC service data unit (MSDU) to be
transferred by the MAC sublayer entity. There is sufficient
information associated with the MSDU for the MAC sublayer entity to
determine the length of the data unit.
</t><t>
The 'type' parameter specifies the value of the MS/TP Frame Type
field that is prepended to the frame by the local MAC sublayer entity.
</t>
</section>
<section title="When Generated">
<t>
This primitive is generated by the MAC client entity whenever data
shall be transferred to a peer entity or entities. This can be in
response to a request from higher protocol layers or from data
generated internally to the MAC client, such as a Token frame.
</t>
</section>
<section title="Effect on Receipt">
<t>
Receipt of this primitive will cause the MAC entity to insert all MAC
specific fields, including Destination Address, Source Address, Frame
Type, and any fields that are unique to the particular media access
method, and pass the properly formed frame to the lower protocol
layers for transfer to the peer MAC sublayer entity or entities.
</t>
</section>
</section>
<section title="MA-DATA.indication">
<section title="Function">
<t>
This primitive defines the transfer of data from the MAC sublayer
entity to the MAC client entity or entities in the case of a broadcast
address.
</t>
</section>
<section title="Semantics of the Service Primitive">
<figure>
<artwork>
The semantics of the primitive are as follows:
MA-DATA.indication (
destination_address,
source_address,
data,
type
)
</artwork>
</figure>
<t>
The 'destination_address' parameter may be either an individual or a
broadcast address as specified by the Destination Address field of
the incoming frame. The 'source_address' parameter is an individual
address as specified by the Source Address field of the incoming
frame.
</t><t>
The 'data' parameter specifies the MAC service data unit (MSDU) as
received by the local MAC entity. There is sufficient information
associated with the MSDU for the MAC sublayer client to determine the
length of the data unit.
</t><t>
The 'type' parameter is the value of the MS/TP Frame Type field of
the incoming frame.
</t>
</section>
<section title="When Generated">
<t>
The MA_DATA.indication is passed from the MAC sublayer entity to the
MAC client entity or entities to indicate the arrival of a frame to
the local MAC sublayer entity that is destined for the MAC client.
Such frames are reported only if they are validly formed, received
without error, and their destination address designates the local MAC
entity. Frames destined for the MAC Control sublayer are not passed
to the MAC client.
</t>
</section>
<section title="Effect on Receipt">
<t>
The effect of receipt of this primitive by the MAC client is unspecified.
</t>
</section>
</section>
</section>
<section anchor="app-b" title="Consistent Overhead Byte Stuffing [COBS]">
<t>
This Appendix is informative and not part of the standard.
</t><t>
BACnet <xref target="Addendum_an"/> corrects a long-standing
issue with the MS/TP specification; namely that preamble sequences
were not escaped whenever they appeared in the Data or Data CRC
fields. In rare cases, this resulted in dropped frames due to loss
of frame synchronization. The solution is to encode the Data and
32-bit Data CRC fields before transmission using Consistent Overhead
Byte Stuffing <xref target="COBS"/> and decode these fields upon reception.
</t><t>
COBS is a run-length encoding method that nominally removes '0x00'
octets from its input. Any selected octet value may be removed by
XOR'ing that value with each octet of the COBS output. BACnet <xref target="Addendum_an"/> specifies
the preamble octet '0x55' for removal.
</t><t>
The minimum overhead of COBS is one octet per encoded field.
The worst-case overhead in long fields is bounded to one octet per 254,
or less than 0.4%, as described in <xref target="COBS"/>.
</t><t>
Frame encoding proceeds logically in two passes. The Encoded Data
field is prepared by passing the MSDU through the COBS encoder and
XOR'ing the preamble octet '0x55' with each octet of the output.
The Encoded CRC-32K field is then prepared by calculating a CRC-32K
over the Encoded Data field and formatting it for transmission as
described in <xref target="app-c"/>. The combined length of these
fields, minus two octets for compatibility with existing MS/TP devices,
is placed in the MS/TP header Length field before transmission.
</t><t>
Example COBS encoder and decoder functions are shown below for
illustration. Complete examples of use and test vectors are provided in
BACnet <xref target="Addendum_an"/>.
</t>
<figure>
<artwork><![CDATA[
#include <stddef.h>
#include <stdint.h>
/*
* Encodes 'length' octets of data located at 'from' and
* writes one or more COBS code blocks at 'to', removing any
* 'mask' octets that may present be in the encoded data.
* Returns the length of the encoded data.
*/
size_t
cobs_encode (uint8_t *to, const uint8_t *from, size_t length,
uint8_t mask)
{
size_t code_index = 0;
size_t read_index = 0;
size_t write_index = 1;
uint8_t code = 1;
uint8_t data, last_code;
while (read_index < length) {
data = from[read_index++];
/*
* In the case of encountering a non-zero octet in the data,
* simply copy input to output and increment the code octet.
*/
if (data != 0) {
to[write_index++] = data ^ mask;
code++;
if (code != 255)
continue;
}
/*
* In the case of encountering a zero in the data or having
* copied the maximum number (254) of non-zero octets, store
* the code octet and reset the encoder state variables.
*/
last_code = code;
to[code_index] = code ^ mask;
code_index = write_index++;
code = 1;
}
/*
* If the last chunk contains exactly 254 non-zero octets, then
* this exception is handled above (and returned length must be
* adjusted). Otherwise, encode the last chunk normally, as if
* a "phantom zero" is appended to the data.
*/
if ((last_code == 255) && (code == 1))
write_index--;
else
to[code_index] = code ^ mask;
return write_index;
}
]]></artwork>
</figure>
<t>
<vspace blankLines='2' /> <!-- page break -->
</t>
<figure>
<artwork><![CDATA[
#include <stddef.h>
#include <stdint.h>
/*
* Decodes 'length' octets of data located at 'from' and
* writes the original client data at 'to', restoring any
* 'mask' octets that may present in the encoded data.
* Returns the length of the encoded data or zero if error.
*/
size_t
cobs_decode (uint8_t *to, const uint8_t *from, size_t length,
uint8_t mask)
{
size_t read_index = 0;
size_t write_index = 0;
uint8_t code, last_code;
while (read_index < length) {
code = from[read_index] ^ mask;
last_code = code;
/*
* Sanity check the encoding to prevent the while() loop below
* from overrunning the output buffer.
*/
if (read_index + code > length)
return 0;
read_index++;
while (--code > 0)
to[write_index++] = from[read_index++] ^ mask;
/*
* Restore the implicit zero at the end of each decoded block
* except when it contains exactly 254 non-zero octets or the
* end of data has been reached.
*/
if ((last_code != 255) && (read_index < length))
to[write_index++] = 0;
}
return write_index;
}
]]></artwork>
</figure>
</section>
<section anchor="app-c" title="Encoded CRC-32K [CRC32K]">
<t>
This Appendix is informative and not part of the standard.
</t><t>
Extending the payload of MS/TP to 1500 octets required upgrading the
Data CRC from 16 bits to 32 bits. P.Koopman has authored several
papers on evaluating CRC polynomials for network applications. In
<xref target="CRC32K"/>, he surveyed the entire 32-bit polynomial space and noted
some that exceed the <xref target="IEEE.802.3"/> polynomial in performance. BACnet
<xref target="Addendum_an"/> specifies the CRC-32K (Koopman) polynomial.
</t><t>
The specified use of the calc_crc32K() function is as follows.
Before a frame is transmitted, 'crc_value' is initialized to all
ones. After passing each octet of the <xref target="COBS"/> Encoded Data through
the function, the ones complement of the resulting 'crc_value' is
arranged in LSB-first order and is itself <xref target="COBS"/> encoded. The length
of the resulting Encoded CRC-32K field is always five octets.
</t><t>
Upon reception of a frame, 'crc_value' is initialized to all ones.
The octets of the Encoded Data field are accumulated
by the calc_crc32K() function before decoding. The Encoded CRC-32K
field is then decoded and the resulting four octets are accumulated
by the calc_crc32K() function. If the result is the expected residue
value 'CRC32K_RESIDUE', then the frame was received correctly.
</t><t>
An example CRC-32K function in shown below for illustration. Complete
examples of use and test vectors are provided in BACnet <xref target="Addendum_an"/>.
</t>
<figure>
<artwork><![CDATA[
#include <stdint.h>
/* See BACnet Addendum 135-2012an, section G.3.2 */
#define CRC32K_INITIAL_VALUE (0xFFFFFFFF)
#define CRC32K_RESIDUE (0x0843323B)
/* CRC-32K polynomial, 1 + x**1 + ... + x**30 (+ x**32) */
#define CRC32K_POLY (0xEB31D82E)
/*
* Accumulate 'data_value' into the CRC in 'crc_value'.
* Return updated CRC.
*
* Note: crc_value must be set to CRC32K_INITIAL_VALUE
* before initial call.
*/
uint32_t
calc_crc32K (uint8_t data_value, uint32_t crc_value)
{
int b;
for (b = 0; b < 8; b++) {
if ((data_value & 1) ^ (crc_value & 1)) {
crc_value >>= 1;
crc_value ^= CRC32K_POLY;
} else {
crc_value >>= 1;
}
data_value >>= 1;
}
return crc_value;
}
]]></artwork>
</figure>
<t>
<vspace blankLines='100' /> <!-- page break -->
</t>
</section>
<section anchor="app-d" title="Example 6LoBAC Packet Decode">
<t>
This Appendix is informative and not part of the standard.
</t>
<figure>
<artwork><![CDATA[
BACnet MS/TP, Src (2), Dst (1), IPv6 Encapsulation
Preamble 55: 0x55
Preamble FF: 0xff
Frame Type: IPv6 Encapsulation (34)
Destination Address: 1
Source Address: 2
Length: 537
Header CRC: 0x1c [correct]
Extended Data CRC: 0x9e7259e2 [correct]
6LoWPAN
IPHC Header
011. .... = Pattern: IP header compression (0x03)
...1 1... .... .... = Traffic class and flow label:
Version, traffic class, and flow label
compressed (0x0003)
.... .0.. .... .... = Next header: Inline
.... ..00 .... .... = Hop limit: Inline (0x0000)
.... .... 1... .... = Context identifier extension: True
.... .... .1.. .... = Source address compression: Stateful
.... .... ..01 .... = Source address mode:
64-bits inline (0x0001)
.... .... .... 0... = Multicast address compression: False
.... .... .... .1.. = Destination address compression:
Stateful
.... .... .... ..10 = Destination address mode:
16-bits inline (0x0002)
0000 .... = Source context identifier: 0x00
.... 0000 = Destination context identifier: 0x00
[Source context: aaaa:: (aaaa::)]
[Destination context: aaaa:: (aaaa::)]
Next header: ICMPv6 (0x3a)
Hop limit: 63
Source: aaaa::1 (aaaa::1)
Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1)
Internet Protocol Version 6, Src: aaaa::1 (aaaa::1),
Dst: aaaa::ff:fe00:1 (aaaa::ff:fe00:1)
0110 .... .... .... .... .... .... .... = Version: 6
.... 0000 0000 .... .... .... .... .... = Traffic class:
0x00000000
.... 0000 00.. .... .... .... .... .... = Differentiated
Services Field:
Default (0x00000000)
.... .... ..0. .... .... .... .... .... = ECN-Capable Transport
(ECT): Not set
.... .... ...0 .... .... .... .... .... = ECN-CE: Not set
.... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
Payload length: 518
Next header: ICMPv6 (58)
Hop limit: 63
Source: aaaa::1 (aaaa::1)
Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1)
Internet Control Message Protocol v6
Type: Echo (ping) request (128)
Code: 0
Checksum: 0x783f [correct]
Identifier: 0x2ee5
Sequence: 2
[Response In: 5165]
Data (510 bytes)
Data: e4dbe8553ba0040008090a0b0c0d0e0f1011121314151617...
[Length: 510]
]]></artwork>
</figure>
<t>
<vspace blankLines='100' /> <!-- page break -->
</t>
<figure>
<artwork><![CDATA[
Frame (547 bytes):
55 ff 22 01 02 02 19 1c 56 2d 83 56 6f 6a 54 54 U.".....V-.VojTT
54 54 54 54 57 54 56 54 d5 50 2d 6a 7b b0 5c 57 TTTTWTVT.P-j{.\W
b1 8e bd 00 6e f5 51 ac 5d 5c 5f 5e 59 58 5b 5a ....n.Q.]\_^YX[Z
45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ
75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z
65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj
15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................
05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................
35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=<?>98;:
25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+*
d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................
c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................
f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................
e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................
95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................
85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................
b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................
a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 ab aa ................
ab 54 57 56 51 50 53 52 5d 5c 5f 5e 59 58 5b 5a .TWVQPSR]\_^YX[Z
45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ
75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z
65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj
15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................
05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................
35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=<?>98;:
25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+*
d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................
c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................
f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................
e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................
95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................
85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................
b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................
a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 50 cb ..............P.
27 0c b7 '..
]]></artwork>
</figure>
<t>
<vspace blankLines='100' /> <!-- page break -->
</t>
<figure>
<artwork><![CDATA[
Decoded Data and CRC32K (537 bytes):
78 d6 00 3a 3f 00 00 00 00 00 00 00 01 00 01 80 x..:?...........
00 78 3f 2e e5 00 02 e4 db e8 55 3b a0 04 00 08 .x?.......U;....
09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................
19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'(
29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678
39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH
49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX
59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh
69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx
79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~..........
89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................
99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................
a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................
b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................
c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................
d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................
e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................
f9 fa fb fc fd fe ff 00 01 02 03 04 05 06 07 08 ................
09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................
19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'(
29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678
39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH
49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX
59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh
69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx
79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~..........
89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................
99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................
a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................
b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................
c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................
d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................
e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................
f9 fa fb fc fd 9e 72 59 e2 ......rY.
]]></artwork>
</figure>
<t>
<vspace blankLines='100' /> <!-- page break -->
</t>
<figure>
<artwork><![CDATA[
Decompressed 6LoWPAN IPHC (558 bytes):
60 00 00 00 02 06 3a 3f aa aa 00 00 00 00 00 00 `.....:?........
00 00 00 00 00 00 00 01 aa aa 00 00 00 00 00 00 ................
00 00 00 ff fe 00 00 01 80 00 78 3f 2e e5 00 02 ..........x?....
e4 db e8 55 3b a0 04 00 08 09 0a 0b 0c 0d 0e 0f ...U;...........
10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................
20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./
30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>?
40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_
60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno
70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~.
80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................
90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................
a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................
b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................
c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................
d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................
e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................
f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff ................
00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f ................
10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................
20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./
30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>?
40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_
60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno
70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~.
80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................
90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................
a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................
b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................
c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................
d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................
e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................
f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd ..............
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| PAFTECH AB 2003-2026 | 2026-04-22 05:35:28 |