1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
|
<pre>Network Working Group L. Dondeti, Ed.
Request for Comments: 5159 QUALCOMM, Inc.
Category: Informational A. Jerichow
Nokia Siemens Networks
March 2008
<span class="h1">Session Description Protocol (SDP) Attributes for</span>
<span class="h1">Open Mobile Alliance (OMA) Broadcast (BCAST)</span>
<span class="h1">Service and Content Protection</span>
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Abstract
This document provides descriptions of Session Description Protocol
(SDP) attributes used by the Open Mobile Alliance's Broadcast Service
and Content Protection specification.
Table of Contents
<a href="#section-1">1</a>. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-2">2</a>
<a href="#section-2">2</a>. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-2">2</a>
<a href="#section-3">3</a>. New SDP Attributes . . . . . . . . . . . . . . . . . . . . . . <a href="#page-2">2</a>
<a href="#section-4">4</a>. Security Considerations . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-5">5</a>. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-5.1">5.1</a>. Registration of New SDP Attributes . . . . . . . . . . . . <a href="#page-3">3</a>
5.1.1. Registration of the Attribute
bcastversion:<major>.<minor> . . . . . . . . . . . . . <a href="#page-3">3</a>
5.1.2. Registration of the Attribute stkmstream:<id of
the stkm stream> . . . . . . . . . . . . . . . . . . . <a href="#page-4">4</a>
5.1.3. Registration of the Attribute
SRTPAuthentication:<id for SRTP authentication
algorithm value> . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
5.1.4. Registration of the Attribute SRTPROCTxRate:<ROC
transmission rate> . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-6">6</a>. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-7">7</a>. References . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-7.1">7.1</a>. Normative References . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-7.2">7.2</a>. Informative References . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<span class="grey">Dondeti & Jerichow Informational [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
The Open Mobile Alliance (OMA) Broadcast (BCAST) group is specifying
service and content protection mechanisms for broadcast services over
wireless networks. As part of that specification, several new SDP
attributes are necessary to allow the broadcast server to signal the
service and content protection parameters to clients.
<a href="./rfc4566#section-8.2.4">Section 8.2.4 of RFC 4566</a> [<a href="#ref-1" title=""SDP: Session Description Protocol"">1</a>] requires that new SDP attributes are
registered through IANA with name, contact information, and
description (and other similar parameters). A standards track
specification is RECOMMENDED if the new attribute(s) will have
widespread use and interoperability considerations.
OMA BCAST specifications are expected to be used by broadcast
wireless systems that are based on 3rd Generation Partnership Project
(3GPP) Multimedia Broadcast/Multicast Service (MBMS), 3GPP2 Broadcast
and Multicast Services (BCMCS), and Digital Video Broadcasting -
Handheld (DVB-H). Although this would typically be considered a
"widespread" use, in this case IETF chose to use a non-standards-
track RFC to register the SDP attributes because OMA maintains change
control of the documents that specify the interpretation of the
values in the attributes.
This document provides descriptions of the SDP attributes used in the
OMA BCAST Service and Content Protection specification [<a href="#ref-2" title=""Service and Content Protection for Mobile Broadcast Services"">2</a>].
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Terminology</span>
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 <a href="./rfc2119">RFC 2119</a> [<a href="#ref-3" title=""Key words for use in RFCs to Indicate Requirement Levels"">3</a>].
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. New SDP Attributes</span>
The following new SDP attributes have been specified:
o a=bcastversion:<major>.<minor>
o a=stkmstream:<id of the stkm stream>
o a=SRTPAuthentication:<id for SRTP authentication algorithm value>
o a=SRTPROCTxRate:<ROC transmission rate>
See <a href="#section-5">Section 5</a> for details on IANA considerations.
<span class="grey">Dondeti & Jerichow Informational [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Security Considerations</span>
In addition to the notes in <a href="./rfc4566#section-7">Section 7 of RFC 4566</a> [<a href="#ref-1" title=""SDP: Session Description Protocol"">1</a>], the following
considerations may be applicable:
The bcastversion parameter indicates the version of the broadcast
system used for distribution of broadcast content. In case future
versions indicated by this parameter allow for enhanced or additional
security features, the bcastversion parameter, if unprotected, could
be utilized for downgrade attacks.
The stkmstream parameter provides references to relevant key
management streams so that receivers can map the media streams to key
streams and retrieve the necessary keys to decrypt media. As such,
this parameter could be utilized, if unprotected, for denial-of-
service (DoS) attacks.
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. IANA Considerations</span>
Per this document, which follows the guidelines of [<a href="#ref-5" title="">5</a>], IANA has
registered a number of SDP attributes.
<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Registration of New SDP Attributes</span>
IANA has registered a number of OMA BCAST only attributes in the
Session Description Protocol Parameters registry [<a href="#ref-1" title=""SDP: Session Description Protocol"">1</a>]. The
registration data, according to <a href="./rfc4566">RFC 4566</a> [<a href="#ref-1" title=""SDP: Session Description Protocol"">1</a>] follows.
The registration templates below refer to the OMA-TS-
BCAST_SvcCntProtection specification [<a href="#ref-2" title=""Service and Content Protection for Mobile Broadcast Services"">2</a>].
<span class="h4"><a class="selflink" id="section-5.1.1" href="#section-5.1.1">5.1.1</a>. Registration of the Attribute bcastversion:<major>.<minor></span>
Contact: Anja Jerichow <anja.jerichow@nsn.com>
Phone: +49 89 636-45868
Attribute name: bcastversion
Long-form attribute name: BCAST version
Type of attribute: session level
This attribute is not dependent on charset.
<span class="grey">Dondeti & Jerichow Informational [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
Purpose: This attribute specifies the OMA BCAST version
"bcastversion" value in the format x.y.
Specification of attribute values: This attribute has a mandatory
value of the form <major>.<minor>, where <major> and <minor> are
non-negative decimal numbers. The att-value field is of XML data
type decimal. For details, see OMA-TS-BCAST_SvcCntProtection,
<a href="#section-10.1.1">Section 10.1.1</a>.
<span class="h4"><a class="selflink" id="section-5.1.2" href="#section-5.1.2">5.1.2</a>. Registration of the Attribute stkmstream:<id of the stkm stream></span>
Contact: Anja Jerichow <anja.jerichow@nsn.com>
Phone: +49 89 636-45868
Attribute name: stkmstream
Long-form attribute name: Short Term Key Message stream identifier
Type of attribute: session level or media level
The attribute can be at session level, in which case it applies to
all media streams, or it can be at media level, in which case it
only applies to the specified media and would overwrite possible
session-level attributes.
This attribute is not dependent on charset.
Purpose: The stkmstream attribute specifies the mapping of Short
Term Key Message streams to media streams in the SDP.
Each session or media stream can have multiple stkmstream
attributes. By comparing the value of this attribute with the
identifier of each STKM stream, the terminal can figure out which
one to listen to and process. We note that this attribute is
optional and hence would not be there for unencrypted media
streams.
Specification of attribute values: This attribute has a mandatory
value of the form <id of the stkm stream>, a unique non-zero
integer identifying a particular key stream. Numbers are unique
within a particular SDP session, i.e., no global numbering is
required. The att-value field is of XML data type unsignedShort.
For details, see OMA-TS-BCAST_SvcCntProtection, <a href="#section-10.1.3">Section 10.1.3</a>.
<span class="grey">Dondeti & Jerichow Informational [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
<span class="h4"><a class="selflink" id="section-5.1.3" href="#section-5.1.3">5.1.3</a>. Registration of the Attribute SRTPAuthentication:<id for SRTP</span>
<span class="h4"> authentication algorithm value></span>
Contact: Anja Jerichow <anja.jerichow@nsn.com>
Phone: +49 89 636-45868
Attribute name: SRTPAuthentication
Long-form attribute name: SRTP authentication algorithm value
identifier
Type of attribute: media level
This attribute is not dependent on charset.
Purpose: When SRTP is used, the attribute SRTPAuthentication states
which authentication algorithm to use.
Specification of attribute values: Based on [<a href="#ref-4" title=""Integrity Transform Carrying Roll-Over Counter for the Secure Real-time Transport Protocol (SRTP)"">4</a>], the identifier is a
transform-independent parameter of the cryptographic context for
SRTP in integer format.
One of the following three integrity transforms registered for the
three modes MUST be used: value "2" for RCCm1, "3" for RCCm2, and
"4" for RCCm3. For details, see OMA-TS-BCAST_SvcCntProtection,
<a href="#section-10.4">Section 10.4</a>.
<span class="h4"><a class="selflink" id="section-5.1.4" href="#section-5.1.4">5.1.4</a>. Registration of the Attribute SRTPROCTxRate:<ROC transmission</span>
<span class="h4"> rate></span>
Contact: Anja Jerichow <anja.jerichow@nsn.com>
Phone: +49 89 636-45868
Attribute name: SRTPROCTxRate
Long-form attribute name: ROC transmission rate
Type of attribute: media level
This attribute is not dependent on charset.
Purpose: When SRTP is used, the attribute SRTPROCTxRate defines the
ROC transmission rate, R.
<span class="grey">Dondeti & Jerichow Informational [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
Specification of attribute values: The attribute value MUST be a
decimal integer R between 1 and 65535 inclusive, as specified in
[<a href="#ref-4" title=""Integrity Transform Carrying Roll-Over Counter for the Secure Real-time Transport Protocol (SRTP)"">4</a>]. If the ROC transmission rate is not included in the
negotiation, the default value of 1 SHALL be used. For details,
see OMA-TS-BCAST_SvcCntProtection, <a href="#section-10.4">Section 10.4</a>.
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. Acknowledgments</span>
Many thanks to Hosame Abu-Amara, Francois Ambrosini, David
Castleford, Miguel Garcia, Alfred Hoenes, Charles Lo, and Uwe
Rauschenbach for their help and support.
<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. References</span>
<span class="h3"><a class="selflink" id="section-7.1" href="#section-7.1">7.1</a>. Normative References</span>
[<a id="ref-1">1</a>] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", <a href="./rfc4566">RFC 4566</a>, July 2006.
[<a id="ref-2">2</a>] Open Mobile Alliance, "Service and Content Protection for Mobile
Broadcast Services", OMA OMA-TS-BCAST_SvcCntProtection-V1_0-
20071218-D, 2007.
[<a id="ref-3">3</a>] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.
[<a id="ref-4">4</a>] Lehtovirta, V., Naslund, M., and K. Norrman, "Integrity
Transform Carrying Roll-Over Counter for the Secure Real-time
Transport Protocol (SRTP)", <a href="./rfc4771">RFC 4771</a>, January 2007.
<span class="h3"><a class="selflink" id="section-7.2" href="#section-7.2">7.2</a>. Informative References</span>
[<a id="ref-5">5</a>] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", <a href="https://www.rfc-editor.org/bcp/bcp26">BCP 26</a>, <a href="./rfc2434">RFC 2434</a>, October 1998.
<span class="grey">Dondeti & Jerichow Informational [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
Authors' Addresses
Lakshminath Dondeti (editor)
QUALCOMM, Inc.
5775 Morehouse Dr
San Diego, CA
USA
Phone: +1 858-845-1267
EMail: ldondeti@qualcomm.com
Anja Jerichow
Nokia Siemens Networks GmbH and Co.KG
Martinstr. 76
81541 Munich
Germany
Phone: +49 89 636-45868
EMail: anja.jerichow@nsn.com
<span class="grey">Dondeti & Jerichow Informational [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc5159">RFC 5159</a> OMA BCAST SDP Attributes March 2008</span>
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a>, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and <a href="https://www.rfc-editor.org/bcp/bcp79">BCP 79</a>.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
<a href="http://www.ietf.org/ipr">http://www.ietf.org/ipr</a>.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Dondeti & Jerichow Informational [Page 8]
</pre>
|
