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2 Network Working Group C. Jennings
3 Internet-Draft Cisco
4 Intended status: Standards Track Z. Shelby
5 Expires: September 21, 2016 ARM
6 J. Arkko
7 A. Keranen
8 Ericsson
9 March 20, 2016
11 Media Types for Sensor Markup Language (SenML)
12 draft-jennings-core-senml-05
14 Abstract
16 This specification defines media types for representing simple sensor
17 measurements and device parameters in the Sensor Markup Language
18 (SenML). Representations are defined in JavaScript Object Notation
19 (JSON), Concise Binary Object Representation (CBOR), eXtensible
20 Markup Language (XML), and Efficient XML Interchange (EXI), which
21 share the common SenML data model. A simple sensor, such as a
22 temperature sensor, could use this media type in protocols such as
23 HTTP or CoAP to transport the measurements of the sensor or to be
24 configured.
26 Status of This Memo
28 This Internet-Draft is submitted in full conformance with the
29 provisions of BCP 78 and BCP 79.
31 Internet-Drafts are working documents of the Internet Engineering
32 Task Force (IETF). Note that other groups may also distribute
33 working documents as Internet-Drafts. The list of current Internet-
34 Drafts is at http://datatracker.ietf.org/drafts/current/.
36 Internet-Drafts are draft documents valid for a maximum of six months
37 and may be updated, replaced, or obsoleted by other documents at any
38 time. It is inappropriate to use Internet-Drafts as reference
39 material or to cite them other than as "work in progress."
41 This Internet-Draft will expire on September 21, 2016.
43 Copyright Notice
45 Copyright (c) 2016 IETF Trust and the persons identified as the
46 document authors. All rights reserved.
48 This document is subject to BCP 78 and the IETF Trust's Legal
49 Provisions Relating to IETF Documents
50 (http://trustee.ietf.org/license-info) in effect on the date of
51 publication of this document. Please review these documents
52 carefully, as they describe your rights and restrictions with respect
53 to this document. Code Components extracted from this document must
54 include Simplified BSD License text as described in Section 4.e of
55 the Trust Legal Provisions and are provided without warranty as
56 described in the Simplified BSD License.
58 Table of Contents
60 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
61 2. Requirements and Design Goals . . . . . . . . . . . . . . . . 3
62 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
63 4. Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . 5
64 5. Associating Meta-data . . . . . . . . . . . . . . . . . . . . 7
65 6. JSON Representation (application/senml+json) . . . . . . . . 8
66 6.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 9
67 6.1.1. Single Datapoint . . . . . . . . . . . . . . . . . . 9
68 6.1.2. Multiple Datapoints . . . . . . . . . . . . . . . . . 9
69 6.1.3. Multiple Measurements . . . . . . . . . . . . . . . . 10
70 6.1.4. Collection of Resources . . . . . . . . . . . . . . . 11
71 7. CBOR Representation (application/senml+cbor) . . . . . . . . 12
72 8. XML Representation (application/senml+xml) . . . . . . . . . 13
73 9. EXI Representation (application/senml-exi) . . . . . . . . . 15
74 10. Usage Considerations . . . . . . . . . . . . . . . . . . . . 18
75 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
76 11.1. Units Registry . . . . . . . . . . . . . . . . . . . . . 19
77 11.2. Media Type Registration . . . . . . . . . . . . . . . . 21
78 11.2.1. senml+json Media Type Registration . . . . . . . . . 22
79 11.2.2. senml+cbor Media Type Registration . . . . . . . . . 23
80 11.2.3. senml+xml Media Type Registration . . . . . . . . . 24
81 11.2.4. senml-exi Media Type Registration . . . . . . . . . 24
82 11.3. XML Namespace Registration . . . . . . . . . . . . . . . 25
83 11.4. CoAP Content-Format Registration . . . . . . . . . . . . 26
84 12. Security Considerations . . . . . . . . . . . . . . . . . . . 26
85 13. Privacy Considerations . . . . . . . . . . . . . . . . . . . 26
86 14. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 26
87 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
88 15.1. Normative References . . . . . . . . . . . . . . . . . . 27
89 15.2. Informative References . . . . . . . . . . . . . . . . . 28
90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
92 1. Overview
94 Connecting sensors to the internet is not new, and there have been
95 many protocols designed to facilitate it. This specification defines
96 new media types for carrying simple sensor information in a protocol
97 such as HTTP or CoAP called the Sensor Markup Language (SenML). This
98 format was designed so that processors with very limited capabilities
99 could easily encode a sensor measurement into the media type, while
100 at the same time a server parsing the data could relatively
101 efficiently collect a large number of sensor measurements. The
102 markup language can be used for a variety of data flow models, most
103 notably data feeds pushed from a sensor to a collector, and the web
104 resource model where the sensor is requested as a resource
105 representation (e.g., "GET /sensor/temperature").
107 There are many types of more complex measurements and measurements
108 that this media type would not be suitable for. SenML strikes a
109 balance between having some information about the sensor carried with
110 the sensor data so that the data is self describing but it also tries
111 to make that a fairly minimal set of auxiliary information for
112 efficiency reason. Other information about the sensor can be
113 discovered by other methods such as using the CoRE Link Format
114 [RFC6690].
116 SenML is defined by a data model for measurements and simple meta-
117 data about measurements and devices. The data is structured as a
118 single array that contains a series of SenML Records which can each
119 contain attributes such as an unique identifier for the sensor, the
120 time the measurement was made, the unit the measurement is in, and
121 the current value of the sensor. Serializations for this data model
122 are defined for JSON [RFC7159], CBOR [RFC7049], XML, and Efficient
123 XML Interchange (EXI) [W3C.REC-exi-20110310].
125 For example, the following shows a measurement from a temperature
126 gauge encoded in the JSON syntax.
128 [{ "n": "urn:dev:ow:10e2073a01080063", "v":23.1, "u":"Cel" }]
130 In the example above, the array has a single SenML record with a
131 measurement for a sensor named "urn:dev:ow:10e2073a01080063" with a
132 current value of 23.5 degrees Celsius.
134 2. Requirements and Design Goals
136 The design goal is to be able to send simple sensor measurements in
137 small packets on mesh networks from large numbers of constrained
138 devices. Keeping the total size of payload under 80 bytes makes this
139 easy to use on a wireless mesh network. It is always difficult to
140 define what small code is, but there is a desire to be able to
141 implement this in roughly 1 KB of flash on a 8 bit microprocessor.
142 Experience with Google power meter and large scale deployments has
143 indicated that the solution needs to support allowing multiple
144 measurements to be batched into a single HTTP or CoAP request. This
145 "batch" upload capability allows the server side to efficiently
146 support a large number of devices. It also conveniently supports
147 batch transfers from proxies and storage devices, even in situations
148 where the sensor itself sends just a single data item at a time. The
149 multiple measurements could be from multiple related sensors or from
150 the same sensor but at different times.
152 The basic design is an array with a series of measurements. The
153 following example shows two measurements made at different times.
154 The value of a measurement is in the "v" tag, the time of a
155 measurement is in the "t" tag, the "n" tag has a unique sensor name,
156 and the unit of the measurement is carried in the "u" tag.
158 [
159 { "n": "urn:dev:ow:10e2073a01080063",
160 "t": 1276020076, "v":23.5, "u":"Cel" },
161 { "n": "urn:dev:ow:10e2073a01080063",
162 "t": 1276020091, "v":23.6, "u":"Cel" }
163 ]
165 To keep the messages small, it does not make sense to repeat the "n"
166 tag in each SenML Record so there is a concept of a Base Name which
167 is simply a string that is prepended to the Name field of all
168 elements in that record and any records that follow it. So a more
169 compact form of the example above is the following.
171 [
172 { "bn": "urn:dev:ow:10e2073a01080063",
173 "t": 1276020076, "v":23.5, "u":"Cel" },
174 { "t": 1276020091, "v":23.6, "u":"Cel" }
175 ]
177 In the above example the Base Name is in the "bn" tag and the "n"
178 tags in each Record are the empty string so they are omitted. The
179 Base Name also could be put in a separate Record such as in the
180 following example.
182 [
183 { "bn": "urn:dev:ow:10e2073a01080063" },
184 { "t": 1276020076, "v":23.5, "u":"Cel" },
185 { "t": 1276020091, "v":23.6, "u":"Cel" }
186 ]
187 Some devices have accurate time while others do not so SenML supports
188 absolute and relative times. Time is represented in floating point
189 as seconds and values greater than zero represent an absolute time
190 relative to the unix epoch while values of 0 or less represent a
191 relative time in the past from the current time. A simple sensor
192 with no absolute wall clock time might take a measurement every
193 second and batch up 60 of them then send it to a server. It would
194 include the relative time the measurement was made to the time the
195 batch was send in the SenML. The server might have accurate NTP time
196 and use the time it received the data, and the relative offset, to
197 replace the times in the SenML with absolute times before saving the
198 SenML in a document database.
200 3. Terminology
202 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
203 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
204 "OPTIONAL" in this document are to be interpreted as described in
205 [RFC2119].
207 4. Semantics
209 Each SenML representation carries a single array that represents a
210 set of measurements and/or parameters. This array contains a series
211 of objects with several optional attributes described below:
213 Base Name: This is a string that is prepended to the names found in
214 the entries. This attribute is optional. This applies to the
215 entries in all Records. A Base Name can only be included in the
216 first Record of the array.
218 Base Time: A base time that is added to the time found in an entry.
219 This attribute is optional. This applies to the entries in all
220 Records. A Base Time can only be included in the first Record of
221 the array.
223 Base Unit: A base unit that is assumed for all entries, unless
224 otherwise indicated. This attribute is optional. If a record
225 does not contain a unit value, then the base unit is used
226 otherwise the value of found in the Unit is used. This applies to
227 the entries in all Records. A Base Unit can only be included in
228 the first object of the array.
230 Links: An array of objects that can be used for additional
231 information. A Links element can only be included in the first
232 object of the array. Each object in the Link array is constrained
233 to being a map of strings to strings with unique keys.
235 Version: Version number of media type format. This attribute is
236 optional positive integer and defaults to 5 if not present. A
237 Version can only be included in the first object of the array.
239 Name: Name of the sensor or parameter. When appended to the Base
240 Name attribute, this must result in a globally unique identifier
241 for the resource. The name is optional, if the Base Name is
242 present. If the name is missing, Base Name must uniquely identify
243 the resource. This can be used to represent a large array of
244 measurements from the same sensor without having to repeat its
245 identifier on every measurement.
247 Unit: Units for a measurement value. Optional. If the Record has
248 not Unit, the Base Unit is used as the Unit. Having no Unit and
249 no Base Unit is allowed.
251 Value Value of the entry. Optional if a Sum value is present,
252 otherwise required. Values are represented using three basic data
253 types, Floating point numbers ("v" field for "Value"), Booleans
254 ("vb" for "Boolean Value"), Strings ("vs" for "String Value") and
255 Data ("vd" for "Binary Data Value") . Exactly one of these three
256 fields MUST appear unless there is Sum field in which case it is
257 allowed to have no Value field or to have "v" field.
259 Sum: Integrated sum of the values over time. Optional. This
260 attribute is in the units specified in the Unit value multiplied
261 by seconds.
263 Time: Time when value was recorded. Optional.
265 Update Time: An optional time in seconds that represents the maximum
266 time before this sensor will provide an updated reading for a
267 measurement. This can be used to detect the failure of sensors or
268 communications path from the sensor.
270 The SenML format can be extended with further custom attributes.
271 TODO - describe what extensions are possible and how to do them.
273 Systems reading one of the objects MUST check for the Version
274 attribute. If this value is a version number larger than the version
275 which the system understands, the system SHOULD NOT use this object.
276 This allows the version number to indicate that the object contains
277 mandatory to understand attributes. New version numbers can only be
278 defined in an RFC that updates this specification or it successors.
280 The Name value is concatenated to the Base Name value to get the name
281 of the sensor. The resulting name needs to uniquely identify and
282 differentiate the sensor from all others. If the object is a
283 representation resulting from the request of a URI [RFC3986], then in
284 the absence of the Base Name attribute, this URI is used as the
285 default value of Base Name. Thus in this case the Name field needs
286 to be unique for that URI, for example an index or subresource name
287 of sensors handled by the URI.
289 Alternatively, for objects not related to a URI, a unique name is
290 required. In any case, it is RECOMMENDED that the full names are
291 represented as URIs or URNs [RFC2141]. One way to create a unique
292 name is to include some bit string that has guaranteed uniqueness
293 (such as a 1-wire address) that is assigned to the device. Some of
294 the examples in this draft use the device URN type as specified in
295 [I-D.arkko-core-dev-urn]. UUIDs [RFC4122] are another way to
296 generate a unique name. TODO - discuss privacy implications of
297 stable hardware addresses.
299 The resulting concatenated name MUST consist only of characters out
300 of the set "A" to "Z", "a" to "z", "0" to "9", "-", ":", ".", or "_"
301 and it MUST start with a character out of the set "A" to "Z", "a" to
302 "z", or "0" to "9". This restricted character set was chosen so that
303 these names can be directly used as in other types of URI including
304 segments of an HTTP path with no special encoding and can be directly
305 used in many databases and analytic systems. [RFC5952] contains
306 advice on encoding an IPv6 address in a name.
308 If either the Base Time or Time value is missing, the missing
309 attribute is considered to have a value of zero. The Base Time and
310 Time values are added together to get the time of measurement. A
311 time of zero indicates that the sensor does not know the absolute
312 time and the measurement was made roughly "now". A negative value is
313 used to indicate seconds in the past from roughly "now". A positive
314 value is used to indicate the number of seconds, excluding leap
315 seconds, since the start of the year 1970 in UTC.
317 Representing the statistical characteristics of measurements, such as
318 accuracy, can be very complex. Future specification may add new
319 attributes to provide better information about the statistical
320 properties of the measurement.
322 5. Associating Meta-data
324 SenML is designed to carry the minimum dynamic information about
325 measurements, and for efficiency reasons does not carry significant
326 static meta-data about the device, object or sensors. Instead, it is
327 assumed that this meta-data is carried out of band. For web
328 resources using SenML representations, this meta-data can be made
329 available using the CoRE Link Format [RFC6690]. The most obvious use
330 of this link format is to describe that a resource is available in a
331 SenML format in the first place. The relevant media type indicator
332 is included in the Content-Type (ct=) attribute.
334 6. JSON Representation (application/senml+json)
336 Record atributes:
338 +---------------+------+------------------+
339 | SenML | JSON | Type |
340 +---------------+------+------------------+
341 | Base Name | bn | String |
342 | Base Time | bt | Number |
343 | Base Unit | bu | Number |
344 | Version | ver | Number |
345 | Name | n | String |
346 | Unit | u | String |
347 | Value | v | Floating point |
348 | String Value | vs | String |
349 | Boolean Value | vb | Boolean |
350 | Data Value | vd | String |
351 | Value Sum | s | Floating point |
352 | Time | t | Number |
353 | Update Time | ut | Number |
354 | Links | l | Array of objects |
355 +---------------+------+------------------+
357 The root content consists of an array with and JSON objects for each
358 SenML Record. All the fields in the above table MAY occur in the
359 records with the type specified in the table.
361 Only the UTF-8 form of JSON is allowed. Characters in the String
362 Value are encoded using the escape sequences defined in [RFC4627].
363 Characters in the Data Value are base64 encoded with URL safe
364 alphabet as defined in Section 5 of [RFC4648].
366 Systems receiving measurements MUST be able to process the range of
367 floating point numbers that are representable as an IEEE double-
368 precision floating-point numbers [IEEE.754.1985]. The number of
369 significant digits in any measurement is not relevant, so a reading
370 of 1.1 has exactly the same semantic meaning as 1.10. If the value
371 has an exponent, the "e" MUST be in lower case. The mantissa SHOULD
372 be less than 19 characters long and the exponent SHOULD be less than
373 5 characters long. This allows time values to have better than micro
374 second precision over the next 100 years.
376 6.1. Examples
378 TODO - simplify examples
380 TODO - Examples are messed up on if time is an integer or float
382 TODO - Add example with string , data , boolean
384 6.1.1. Single Datapoint
386 The following shows a temperature reading taken approximately "now"
387 by a 1-wire sensor device that was assigned the unique 1-wire address
388 of 10e2073a01080063:
390 [{ "n": "urn:dev:ow:10e2073a01080063", "v":23.1, "u":"Cel" }]
392 6.1.2. Multiple Datapoints
394 The following example shows voltage and current now, i.e., at an
395 unspecified time. The device has an EUI-64 MAC address of
396 0024befffe804ff1.
398 [{"bn": "urn:dev:mac:0024befffe804ff1/"},
399 { "n": "voltage", "t": 0, "u": "V", "v": 120.1 },
400 { "n": "current", "t": 0, "u": "A", "v": 1.2 }
401 ]
403 The next example is similar to the above one, but shows current at
404 Tue Jun 8 18:01:16 UTC 2010 and at each second for the previous 5
405 seconds.
407 [{"bn": "urn:dev:mac:0024befffe804ff1/",
408 "bt": 1276020076,
409 "bu": "A",
410 "ver": 5},
411 { "n": "voltage", "u": "V", "v": 120.1 },
412 { "n": "current", "t": -5, "v": 1.2 },
413 { "n": "current", "t": -4, "v": 1.30 },
414 { "n": "current", "t": -3, "v": 0.14e1 },
415 { "n": "current", "t": -2, "v": 1.5 },
416 { "n": "current", "t": -1, "v": 1.6 },
417 { "n": "current", "t": 0, "v": 1.7 }
418 ]
420 Note that in some usage scenarios of SenML the implementations MAY
421 store or transmit SenML in a stream-like fashion, where data is
422 collected over time and continuously added to the object. This mode
423 of operation is optional, but systems or protocols using SenML in
424 this fashion MUST specify that they are doing this. SenML defines a
425 separate mime type (TODO) to indicate Sensor Streaming Markup
426 Language (SensML) for this usage. In this situation the SensML
427 stream can be sent and received in a partial fashion, i.e., a
428 measurement entry can be read as soon as the SenML Record is received
429 and not have to wait for the full SensML Stream to be complete.
431 For instance, the following stream of measurements may be sent via a
432 long lived HTTP POST from the producer of a SensML to the consumer of
433 that, and each measurement object may be reported at the time it
434 measured:
436 [ {"bn": "http://[2001:db8::1]",
437 "bt": 1320067464,
438 "bu": "%RH"},
439 { "v": 21.2, "t": 0 },
440 { "v": 21.3, "t": 10 },
441 { "v": 21.4, "t": 20 },
442 { "v": 21.4, "t": 30 },
443 { "v": 21.5, "t": 40 },
444 { "v": 21.5, "t": 50 },
445 { "v": 21.5, "t": 60 },
446 { "v": 21.6, "t": 70 },
447 { "v": 21.7, "t": 80 },
448 { "v": 21.5, "t": 90 },
449 ...
451 6.1.3. Multiple Measurements
453 The following example shows humidity measurements from a mobile
454 device with an IPv6 address 2001:db8::1, starting at Mon Oct 31
455 13:24:24 UTC 2011. The device also provides position data, which is
456 provided in the same measurement or parameter array as separate
457 entries. Note time is used to for correlating data that belongs
458 together, e.g., a measurement and a parameter associated with it.
459 Finally, the device also reports extra data about its battery status
460 at a separate time.
462 [{"bn": "http://[2001:db8::1]",
463 "bt": 1320067464,
464 "bu": "%RH"},
465 { "v": 20.0, "t": 0 },
466 { "v": 24.30621, "u": "lon", "t": 0 },
467 { "v": 60.07965, "u": "lat", "t": 0 },
468 { "v": 20.3, "t": 60 },
469 { "v": 24.30622, "u": "lon", "t": 60 },
470 { "v": 60.07965, "u": "lat", "t": 60 },
471 { "v": 20.7, "t": 120 },
472 { "v": 24.30623, "u": "lon", "t": 120 },
473 { "v": 60.07966, "u": "lat", "t": 120 },
474 { "v": 98.0, "u": "%EL", "t": 150 },
475 { "v": 21.2, "t": 180 },
476 { "v": 24.30628, "u": "lon", "t": 180 },
477 { "v": 60.07967, "u": "lat", "t": 180 }
478 ]
480 The size of this example represented in various forms, as well as
481 that form compressed with gzip is given in the following table.
483 +----------+------+-----------------+
484 | Encoding | Size | Compressed Size |
485 +----------+------+-----------------+
486 | JSON | 567 | 200 |
487 | XML | 656 | 232 |
488 | CBOR | 292 | 192 |
489 | EXI | 160 | 183 |
490 +----------+------+-----------------+
492 Table 1: Size Comparisons
494 Note the CBOR and EXI sizes are not using the schema guidance so the
495 could be a bit smaller.
497 6.1.4. Collection of Resources
499 The following example shows how to query one device that can provide
500 multiple measurements. The example assumes that a client has fetched
501 information from a device at 2001:db8::2 by performing a GET
502 operation on http://[2001:db8::2] at Mon Oct 31 16:27:09 UTC 2011,
503 and has gotten two separate values as a result, a temperature and
504 humidity measurement.
506 This example also shows a possible use of the link extension.
508 [{"bn": "http://[2001:db8::2]/",
509 "bt": 1320078429,
510 "ver": 5,
511 "l": [{"href":"humidity","foo":"bar1"},
512 {"href":"temperature","foo":"bar2","bar":"foo3"}]
513 },
514 { "n": "temperature", "v": 27.2, "u": "Cel" },
515 { "n": "humidity", "v": 80, "u": "%RH" }
516 ]
518 7. CBOR Representation (application/senml+cbor)
520 The CBOR [RFC7049] representation is equivalent to the JSON
521 representation, with the following changes:
523 o For compactness, the CBOR representation uses integers for the map
524 keys defined in Table 2. This table is conclusive, i.e., there is
525 no intention to define any additional integer map keys; any
526 extensions will use string map keys.
528 o For JSON Numbers, the CBOR representation can use integers,
529 floating point numbers, or decimal fractions (CBOR Tag 4); the
530 common limitations of JSON implementations are not relevant for
531 these. For the version number, however, only an unsigned integer
532 is allowed.
534 +---------------+------------+------------+
535 | Name | JSON label | CBOR label |
536 +---------------+------------+------------+
537 | Version | ver | -1 |
538 | Base Name | bn | -2 |
539 | Base Time | bt | -3 |
540 | Base Units | bu | -4 |
541 | Links | l | -5 |
542 | Name | n | 0 |
543 | Units | u | 1 |
544 | Value | v | 2 |
545 | String Value | vs | 3 |
546 | Boolean Value | vb | 4 |
547 | Value Sum | s | 5 |
548 | Time | t | 6 |
549 | Update Time | ut | 7 |
550 | Data Value | vd | 8 |
551 +---------------+------------+------------+
553 Table 2: CBOR representation: integers for map keys
555 The following example shows an hexdump of the CBOR example for the
556 same sensor measurement as in Section 6.1.2.
558 0000 88 a4 62 62 6e 78 1d 75 72 6e 3a 64 65 76 3a 6d |..bbnx.urn:dev:m|
559 0010 61 63 3a 30 30 32 34 62 65 66 66 66 65 38 30 34 |ac:0024befffe804|
560 0020 66 66 31 2f 62 62 74 1a 4c 0e 85 6c 62 62 75 61 |ff1/bbt.L..lbbua|
561 0030 41 63 76 65 72 05 a3 61 6e 67 76 6f 6c 74 61 67 |Acver..angvoltag|
562 0040 65 61 75 61 56 61 76 fb 40 5e 06 66 66 66 66 66 |eauaVav.@^.fffff|
563 0050 a3 61 6e 67 63 75 72 72 65 6e 74 61 74 24 61 76 |.angcurrentat$av|
564 0060 fb 3f f3 33 33 33 33 33 33 a3 61 6e 67 63 75 72 |.?.333333.angcur|
565 0070 72 65 6e 74 61 74 23 61 76 fb 3f f4 cc cc cc cc |rentat#av.?.....|
566 0080 cc cd a3 61 6e 67 63 75 72 72 65 6e 74 61 74 22 |...angcurrentat"|
567 0090 61 76 fb 3f f6 66 66 66 66 66 66 a3 61 6e 67 63 |av.?.ffffff.angc|
568 00a0 75 72 72 65 6e 74 61 74 21 61 76 fb 3f f8 00 00 |urrentat!av.?...|
569 00b0 00 00 00 00 a3 61 6e 67 63 75 72 72 65 6e 74 61 |.....angcurrenta|
570 00c0 74 20 61 76 fb 3f f9 99 99 99 99 99 9a a2 61 6e |t av.?........an|
571 00d0 67 63 75 72 72 65 6e 74 61 76 fb 3f fb 33 33 33 |gcurrentav.?.333|
572 00e0 33 33 33 0a |333.|
573 00e4
575 8. XML Representation (application/senml+xml)
577 A SenML Stream can also be represented in XML format as defined in
578 this section. The following example shows an XML example for the
579 same sensor measurement as in Section 6.1.2.
581
582
584
585
586
587
588
589
590
591
593 The SenML Stream is represented as a sensml tag that contains a
594 series of senml tags for each SenML Record. The SenML Fields are
595 represents as XML attributes. The following table shows the mapping
596 the SenML Field names to the attribute used in the XML senml tag.
598 +---------------+-----+---------+
599 | SenML Field | XML | Type |
600 +---------------+-----+---------+
601 | Base Name | bn | string |
602 | Base Time | bt | int |
603 | Base Unit | bu | int |
604 | Links | l | XML tag |
605 | Version | ver | int |
606 | Name | n | string |
607 | Unit | u | string |
608 | Value | v | float |
609 | String Value | vs | string |
610 | Data Value | vd | string |
611 | Boolean Value | vb | boolean |
612 | Value Sum | s | float |
613 | Time | t | int |
614 | Update Time | ut | int |
615 +---------------+-----+---------+
617 TODO - Discuss encoding of String and Data
619 The RelaxNG schema for the XML is:
621 default namespace = "urn:ietf:params:xml:ns:senml"
622 namespace rng = "http://relaxng.org/ns/structure/1.0"
624 link = element l {
625 attribute * { xsd:string }*
626 }
628 senml = element senml {
629 attribute bn { xsd:string }?,
630 attribute bt { xsd:int }?,
631 attribute bu { xsd:string }?,
632 attribute n { xsd:string }?,
633 attribute s { xsd:float }?,
634 attribute t { xsd:int }?,
635 attribute u { xsd:string }?,
636 attribute ut { xsd:int }?,
637 attribute v { xsd:float }?,
638 attribute vb { xsd:boolean }?,
639 attribute ver { xsd:int }?,
640 attribute vs { xsd:string }?,
642 link*
643 }
645 sensml =
646 element sensml {
647 senml+
648 }
650 start = sensml
652 9. EXI Representation (application/senml-exi)
654 For efficient transmission of SenML over e.g. a constrained network,
655 Efficient XML Interchange (EXI) can be used. This encodes the XML
656 Schema structure of SenML into binary tags and values rather than
657 ASCII text. An EXI representation of SenML SHOULD be made using the
658 strict schema-mode of EXI. This mode however does not allow tag
659 extensions to the schema, and therefore any extensions will be lost
660 in the encoding. For uses where extensions need to be preserved in
661 EXI, the non-strict schema mode of EXI MAY be used.
663 The EXI header option MUST be included. An EXI schemaID options MUST
664 be set to the value of "a" indicating the scheme provided in this
665 specification. Future revisions to the schema can change this
666 schemaID to allow for backwards compatibility. When the data will be
667 transported over CoAP or HTTP, an EXI Cookie SHOULD NOT be used as it
668 simply makes things larger and is redundant to information provided
669 in the Content-Type header.
671 TODO - examples probably have the wrong setting the schemaID
673 The following is the XSD Schema to be used for strict schema guided
674 EXI processing. It is generated from the RelaxNG.
676
677
681
682
683
684
685
686
687
688
689
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714 The following shows a hexdump of the EXI produced from encoding the
715 following XML example. Note this example is the same information as
716 the first example in Section 6.1.2 in JSON format.
718
719
720
721
722
724 Which compresses with EXI to the following displayed in hexdump:
726 0000 a0 30 41 cd 95 b9 b5 b0 d4 b9 9d 95 b8 b9 e1 cd |.0A.............|
727 0010 91 00 fb ab 93 71 d3 23 2b b1 d3 6b 0b 19 d1 81 |.....q.#+..k....|
728 0020 81 91 a3 13 2b 33 33 33 29 c1 81 a3 33 31 89 7e |....+333)...31.~|
729 0030 0c 25 d9 bd b1 d1 85 9d 94 80 d5 8a c4 26 01 06 |.%...........&..|
730 0040 12 c6 ea e4 e4 ca dc e8 40 68 24 19 00 90 |........@h$...|
731 004e
733 The above example used the bit packed form of EXI but it is also
734 possible to use a byte packed form of EXI which can makes it easier
735 for a simple sensor to produce valid EXI without really implementing
736 EXI. Consider the example of a temperature sensor that produces a
737 value in tenths of degrees Celsius over a range of 0.0 to 55.0. It
738 would produce an XML SenML file such as:
740
741
742
744 The compressed form, using the byte alignment option of EXI, for the
745 above XML is the following:
747 0000 a0 00 48 82 0e 6c ad cd ad 86 a5 cc ec ad c5 cf |..H..l..........|
748 0010 0e 6c 80 02 03 1d 75 72 6e 3a 64 65 76 3a 6f 77 |.l....urn:dev:ow|
749 0020 3a 31 30 65 32 30 37 33 61 30 31 30 38 30 30 36 |:10e2073a0108006|
750 0030 33 02 05 43 65 6c 01 00 e7 01 01 00 04 01 |3..Cel........|
751 003e
753 A small temperature sensor devices that only generates this one EXI
754 file does not really need an full EXI implementation. It can simple
755 hard code the output replacing the one wire device ID starting at
756 byte 0x16 and going to byte 0x31 with it's device ID, and replacing
757 the value "0xe7 0x01" at location 0x38 to 0x39 with the current
758 temperature. The EXI Specification [W3C.REC-exi-20110310] contains
759 the full information 'on how floating point numbers are represented,
760 but for the purpose of this sensor, the temperature can be converted
761 to an integer in tenths of degrees (231 in this example). EXI stores
762 7 bits of the integer in each byte with the top bit set to one if
763 there are further bytes. So the first bytes at is set to low 7 bits
764 of the integer temperature in tenths of degrees plus 0x80. In this
765 example 231 & 0x7F + 0x80 = 0xE7. The second byte is set to the
766 integer temperature in tenths of degrees right shifted 7 bits. In
767 this example 231 >> 7 = 0x01.
769 10. Usage Considerations
771 The measurements support sending both the current value of a sensor
772 as well as the an integrated sum. For many types of measurements,
773 the sum is more useful than the current value. For example, an
774 electrical meter that measures the energy a given computer uses will
775 typically want to measure the cumulative amount of energy used. This
776 is less prone to error than reporting the power each second and
777 trying to have something on the server side sum together all the
778 power measurements. If the network between the sensor and the meter
779 goes down over some period of time, when it comes back up, the
780 cumulative sum helps reflect what happened while the network was
781 down. A meter like this would typically report a measurement with
782 the units set to watts, but it would put the sum of energy used in
783 the "s" attribute of the measurement. It might optionally include
784 the current power in the "v" attribute.
786 While the benefit of using the integrated sum is fairly clear for
787 measurements like power and energy, it is less obvious for something
788 like temperature. Reporting the sum of the temperature makes it easy
789 to compute averages even when the individual temperature values are
790 not reported frequently enough to compute accurate averages.
791 Implementors are encouraged to report the cumulative sum as well as
792 the raw value of a given sensor.
794 Applications that use the cumulative sum values need to understand
795 they are very loosely defined by this specification, and depending on
796 the particular sensor implementation may behave in unexpected ways.
797 Applications should be able to deal with the following issues:
799 1. Many sensors will allow the cumulative sums to "wrap" back to
800 zero after the value gets sufficiently large.
802 2. Some sensors will reset the cumulative sum back to zero when the
803 device is reset, loses power, or is replaced with a different
804 sensor.
806 3. Applications cannot make assumptions about when the device
807 started accumulating values into the sum.
809 Typically applications can make some assumptions about specific
810 sensors that will allow them to deal with these problems. A common
811 assumption is that for sensors whose measurement values are always
812 positive, the sum should never get smaller; so if the sum does get
813 smaller, the application will know that one of the situations listed
814 above has happened.
816 11. IANA Considerations
818 Note to RFC Editor: Please replace all occurrences of "RFC-AAAA" with
819 the RFC number of this specification.
821 11.1. Units Registry
823 IANA will create a registry of unit symbols. The primary purpose of
824 this registry is to make sure that symbols uniquely map to give type
825 of measurement. Definitions for many of these units can be found in
826 location such as [NIST811] and [BIPM].
828 +--------+--------------------------------------+-------+-----------+
829 | Symbol | Description | Type | Reference |
830 +--------+--------------------------------------+-------+-----------+
831 | m | meter | float | RFC-AAAA |
832 | g | gram | float | RFC-AAAA |
833 | s | second | float | RFC-AAAA |
834 | A | ampere | float | RFC-AAAA |
835 | K | kelvin | float | RFC-AAAA |
836 | cd | candela | float | RFC-AAAA |
837 | mol | mole | float | RFC-AAAA |
838 | Hz | hertz | float | RFC-AAAA |
839 | rad | radian | float | RFC-AAAA |
840 | sr | steradian | float | RFC-AAAA |
841 | N | newton | float | RFC-AAAA |
842 | Pa | pascal | float | RFC-AAAA |
843 | J | joule | float | RFC-AAAA |
844 | W | watt | float | RFC-AAAA |
845 | C | coulomb | float | RFC-AAAA |
846 | V | volt | float | RFC-AAAA |
847 | F | farad | float | RFC-AAAA |
848 | Ohm | ohm | float | RFC-AAAA |
849 | S | siemens | float | RFC-AAAA |
850 | Wb | weber | float | RFC-AAAA |
851 | T | tesla | float | RFC-AAAA |
852 | H | henry | float | RFC-AAAA |
853 | Cel | degrees Celsius | float | RFC-AAAA |
854 | lm | lumen | float | RFC-AAAA |
855 | lx | lux | float | RFC-AAAA |
856 | Bq | becquerel | float | RFC-AAAA |
857 | Gy | gray | float | RFC-AAAA |
858 | Sv | sievert | float | RFC-AAAA |
859 | kat | katal | float | RFC-AAAA |
860 | pH | pH acidity | float | RFC-AAAA |
861 | % | Value of a switch (note 1) | float | RFC-AAAA |
862 | count | counter value | float | RFC-AAAA |
863 | %RH | Relative Humidity | float | RFC-AAAA |
864 | m2 | area | float | RFC-AAAA |
865 | l | volume in liters | float | RFC-AAAA |
866 | m/s | velocity | float | RFC-AAAA |
867 | m/s2 | acceleration | float | RFC-AAAA |
868 | l/s | flow rate in liters per second | float | RFC-AAAA |
869 | W/m2 | irradiance | float | RFC-AAAA |
870 | cd/m2 | luminance | float | RFC-AAAA |
871 | Bspl | bel sound pressure level | float | RFC-AAAA |
872 | bit/s | bits per second | float | RFC-AAAA |
873 | lat | degrees latitude (note 2) | float | RFC-AAAA |
874 | lon | degrees longitude (note 2) | float | RFC-AAAA |
875 | %EL | remaining battery energy level in | float | RFC-AAAA |
876 | | percents | | |
877 | EL | remaining battery energy level in | float | RFC-AAAA |
878 | | seconds | | |
879 | beat/m | Heart rate in beats per minute | float | RFC-AAAA |
880 | beats | Cumulative number of heart beats | float | RFC-AAAA |
881 +--------+--------------------------------------+-------+-----------+
883 Table 3
885 o Note 1: A value of 0.0 indicates the switch is off while 1.0
886 indicates on and 0.5 would be half on.
888 o Note 2: Assumed to be in WGS84 unless another reference frame is
889 known for the sensor.
891 New entries can be added to the registration by either Expert Review
892 or IESG Approval as defined in [RFC5226]. Experts should exercise
893 their own good judgment but need to consider the following
894 guidelines:
896 1. There needs to be a real and compelling use for any new unit to
897 be added.
899 2. Units should define the semantic information and be chosen
900 carefully. Implementors need to remember that the same word may
901 be used in different real-life contexts. For example, degrees
902 when measuring latitude have no semantic relation to degrees
903 when measuring temperature; thus two different units are needed.
905 3. These measurements are produced by computers for consumption by
906 computers. The principle is that conversion has to be easily be
907 done when both reading and writing the media type. The value of
908 a single canonical representation outweighs the convenience of
909 easy human representations or loss of precision in a conversion.
911 4. Use of SI prefixes such as "k" before the unit is not allowed.
912 Instead one can represent the value using scientific notation
913 such a 1.2e3. TODO - Open Issue. Some people would like to
914 have SI prefixes to improve human readability.
916 5. For a given type of measurement, there will only be one unit
917 type defined. So for length, meters are defined and other
918 lengths such as mile, foot, light year are not allowed. For
919 most cases, the SI unit is preferred.
921 6. Symbol names that could be easily confused with existing common
922 units or units combined with prefixes should be avoided. For
923 example, selecting a unit name of "mph" to indicate something
924 that had nothing to do with velocity would be a bad choice, as
925 "mph" is commonly used to mean miles per hour.
927 7. The following should not be used because the are common SI
928 prefixes: Y, Z, E, P, T, G, M, k, h, da, d, c, n, u, p, f, a, z,
929 y, Ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi.
931 8. The following units should not be used as they are commonly used
932 to represent other measurements Ky, Gal, dyn, etg, P, St, Mx, G,
933 Oe, Gb, sb, Lmb, ph, Ci, R, RAD, REM, gal, bbl, qt, degF, Cal,
934 BTU, HP, pH, B/s, psi, Torr, atm, at, bar, kWh.
936 9. The unit names are case sensitive and the correct case needs to
937 be used, but symbols that differ only in case should not be
938 allocated.
940 10. A number after a unit typically indicates the previous unit
941 raised to that power, and the / indicates that the units that
942 follow are the reciprocal. A unit should have only one / in the
943 name.
945 11. A good list of common units can be found in the Unified Code for
946 Units of Measure [UCUM].
948 11.2. Media Type Registration
950 The following registrations are done following the procedure
951 specified in [RFC6838] and [RFC7303].
953 11.2.1. senml+json Media Type Registration
955 Type name: application
957 Subtype name: senml+json and sensml+json
959 Required parameters: none
961 Optional parameters: none
963 Encoding considerations: Must be encoded as using a subset of the
964 encoding allowed in [RFC7159]. See RFC-AAAA for details. This
965 simplifies implementation of very simple system and does not impose
966 any significant limitations as all this data is meant for machine to
967 machine communications and is not meant to be human readable.
969 Security considerations: Sensor data can contain a wide range of
970 information ranging from information that is very public, such the
971 outside temperature in a given city, to very private information that
972 requires integrity and confidentiality protection, such as patient
973 health information. This format does not provide any security and
974 instead relies on the transport protocol that carries it to provide
975 security. Given applications need to look at the overall context of
976 how this media type will be used to decide if the security is
977 adequate.
979 Interoperability considerations: Applications should ignore any JSON
980 key value pairs that they do not understand. This allows backwards
981 compatibility extensions to this specification. The "ver" field can
982 be used to ensure the receiver supports a minimal level of
983 functionality needed by the creator of the JSON object.
985 Published specification: RFC-AAAA
987 Applications that use this media type: The type is used by systems
988 that report electrical power usage and environmental information such
989 as temperature and humidity. It can be used for a wide range of
990 sensor reporting systems.
992 Additional information:
994 Magic number(s): none
996 File extension(s): senml
998 Macintosh file type code(s): none
999 Person & email address to contact for further information: Cullen
1000 Jennings
1002 Intended usage: COMMON
1004 Restrictions on usage: None
1006 Author: Cullen Jennings
1008 Change controller: IESG
1010 11.2.2. senml+cbor Media Type Registration
1012 Type name: application
1014 Subtype name: senml+cbor
1016 Required parameters: none
1018 Optional parameters: none
1020 Encoding considerations: TBD
1022 Security considerations: TBD
1024 Interoperability considerations: TBD
1026 Published specification: RFC-AAAA
1028 Applications that use this media type: The type is used by systems
1029 that report electrical power usage and environmental information such
1030 as temperature and humidity. It can be used for a wide range of
1031 sensor reporting systems.
1033 Additional information:
1035 Magic number(s): none
1037 File extension(s): senml
1039 Macintosh file type code(s): none
1041 Person & email address to contact for further information: Cullen
1042 Jennings
1044 Intended usage: COMMON
1046 Restrictions on usage: None
1047 Author: Cullen Jennings
1049 Change controller: IESG
1051 11.2.3. senml+xml Media Type Registration
1053 Type name: application
1055 Subtype name: senml+xml and sensml+xml
1057 Required parameters: none
1059 Optional parameters: none
1061 Encoding considerations: TBD
1063 Security considerations: TBD
1065 Interoperability considerations: TBD
1067 Published specification: RFC-AAAA
1069 Applications that use this media type: TBD
1071 Additional information:
1073 Magic number(s): none
1075 File extension(s): senml
1077 Macintosh file type code(s): none
1079 Person & email address to contact for further information: Cullen
1080 Jennings
1082 Intended usage: COMMON
1084 Restrictions on usage: None
1086 Author: Cullen Jennings
1088 Change controller: IESG
1090 11.2.4. senml-exi Media Type Registration
1092 Type name: application
1094 Subtype name: senml-exi
1095 Required parameters: none
1097 Optional parameters: none
1099 Encoding considerations: TBD
1101 Security considerations: TBD
1103 Interoperability considerations: TBD
1105 Published specification: RFC-AAAA
1107 Applications that use this media type: TBD
1109 Additional information:
1111 Magic number(s): none
1113 File extension(s): senml
1115 Macintosh file type code(s): none
1117 Person & email address to contact for further information: Cullen
1118 Jennings
1120 Intended usage: COMMON
1122 Restrictions on usage: None
1124 Author: Cullen Jennings
1126 Change controller: IESG
1128 11.3. XML Namespace Registration
1130 This document registers the following XML namespaces in the IETF XML
1131 registry defined in [RFC3688].
1133 URI: urn:ietf:params:xml:ns:senml
1135 Registrant Contact: The IESG.
1137 XML: N/A, the requested URIs are XML namespaces
1139 11.4. CoAP Content-Format Registration
1141 IANA is requested to assign CoAP Content-Format IDs for the SenML
1142 media types in the "CoAP Content-Formats" sub-registry, within the
1143 "CoRE Parameters" registry [RFC7252]. All IDs are assigned from the
1144 "Expert Review" (0-255) range. The assigned IDs are show in Table 4.
1146 +-------------------------+-----+
1147 | Media type | ID |
1148 +-------------------------+-----+
1149 | application/senml+json | TBD |
1150 | application/sensml+json | TBD |
1151 | application/senml+cbor | TBD |
1152 | application/senml+xml | TBD |
1153 | application/sensml+xml | TBD |
1154 | application/senml-exi | TBD |
1155 +-------------------------+-----+
1157 Table 4: CoAP Content-Format IDs
1159 12. Security Considerations
1161 See Section 13. Further discussion of security properties can be
1162 found in Section 11.2.
1164 13. Privacy Considerations
1166 Sensor data can range from information with almost no security
1167 considerations, such as the current temperature in a given city, to
1168 highly sensitive medical or location data. This specification
1169 provides no security protection for the data but is meant to be used
1170 inside another container or transport protocol such as S/MIME or HTTP
1171 with TLS that can provide integrity, confidentiality, and
1172 authentication information about the source of the data.
1174 14. Acknowledgement
1176 We would like to thank Lisa Dusseault, Joe Hildebrand, Lyndsay
1177 Campbell, Martin Thomson, John Klensin, Bjoern Hoehrmann, Carsten
1178 Bormann, and Christian Amsuess for their review comments.
1180 The CBOR Representation text was contributed by Carsten Bormann.
1182 15. References
1183 15.1. Normative References
1185 [BIPM] Bureau International des Poids et Mesures, "The
1186 International System of Units (SI)", 8th edition, 2006.
1188 [IEEE.754.1985]
1189 Institute of Electrical and Electronics Engineers,
1190 "Standard for Binary Floating-Point Arithmetic", IEEE
1191 Standard 754, August 1985.
1193 [NIST811] Thompson, A. and B. Taylor, "Guide for the Use of the
1194 International System of Units (SI)", NIST Special
1195 Publication 811, 2008.
1197 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
1198 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
1199 RFC2119, March 1997,
1200 .
1202 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
1203 DOI 10.17487/RFC3688, January 2004,
1204 .
1206 [RFC4627] Crockford, D., "The application/json Media Type for
1207 JavaScript Object Notation (JSON)", RFC 4627, DOI
1208 10.17487/RFC4627, July 2006,
1209 .
1211 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
1212 Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
1213 .
1215 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
1216 IANA Considerations Section in RFCs", BCP 26, RFC 5226,
1217 DOI 10.17487/RFC5226, May 2008,
1218 .
1220 [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
1221 Specifications and Registration Procedures", BCP 13, RFC
1222 6838, DOI 10.17487/RFC6838, January 2013,
1223 .
1225 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
1226 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
1227 October 2013, .
1229 [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
1230 Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
1231 2014, .
1233 [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
1234 Application Protocol (CoAP)", RFC 7252, DOI 10.17487/
1235 RFC7252, June 2014,
1236 .
1238 [RFC7303] Thompson, H. and C. Lilley, "XML Media Types", RFC 7303,
1239 DOI 10.17487/RFC7303, July 2014,
1240 .
1242 [W3C.REC-exi-20110310]
1243 Schneider, J. and T. Kamiya, "Efficient XML Interchange
1244 (EXI) Format 1.0", World Wide Web Consortium
1245 Recommendation REC-exi-20110310, March 2011,
1246 .
1248 15.2. Informative References
1250 [I-D.arkko-core-dev-urn]
1251 Arkko, J., Jennings, C., and Z. Shelby, "Uniform Resource
1252 Names for Device Identifiers", draft-arkko-core-dev-urn-03
1253 (work in progress), July 2012.
1255 [RFC2141] Moats, R., "URN Syntax", RFC 2141, DOI 10.17487/RFC2141,
1256 May 1997, .
1258 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
1259 Resource Identifier (URI): Generic Syntax", STD 66, RFC
1260 3986, DOI 10.17487/RFC3986, January 2005,
1261 .
1263 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
1264 Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI
1265 10.17487/RFC4122, July 2005,
1266 .
1268 [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
1269 Address Text Representation", RFC 5952, DOI 10.17487/
1270 RFC5952, August 2010,
1271 .
1273 [RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
1274 Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
1275 .
1277 [UCUM] Schadow, G. and C. McDonald, "The Unified Code for Units
1278 of Measure (UCUM)", Regenstrief Institute and Indiana
1279 University School of Informatics, 2013,
1280 .
1282 Authors' Addresses
1284 Cullen Jennings
1285 Cisco
1286 400 3rd Avenue SW
1287 Calgary, AB T2P 4H2
1288 Canada
1290 Phone: +1 408 421-9990
1291 Email: fluffy@cisco.com
1293 Zach Shelby
1294 ARM
1295 150 Rose Orchard
1296 San Jose 95134
1297 USA
1299 Phone: +1-408-203-9434
1300 Email: zach.shelby@arm.com
1302 Jari Arkko
1303 Ericsson
1304 Jorvas 02420
1305 Finland
1307 Email: jari.arkko@piuha.net
1309 Ari Keranen
1310 Ericsson
1311 Jorvas 02420
1312 Finland
1314 Email: ari.keranen@ericsson.com