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
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
|
<pre>Internet Engineering Task Force (IETF) B. Carpenter
Request for Comments: 7136 Univ. of Auckland
Updates: <a href="./rfc4291">4291</a> S. Jiang
Category: Standards Track Huawei Technologies Co., Ltd
ISSN: 2070-1721 February 2014
<span class="h1">Significance of IPv6 Interface Identifiers</span>
Abstract
The IPv6 addressing architecture includes a unicast interface
identifier that is used in the creation of many IPv6 addresses.
Interface identifiers are formed by a variety of methods. This
document clarifies that the bits in an interface identifier have no
meaning and that the entire identifier should be treated as an opaque
value. In particular, <a href="./rfc4291">RFC 4291</a> defines a method by which the
Universal and Group bits of an IEEE link-layer address are mapped
into an IPv6 unicast interface identifier. This document clarifies
that those two bits are significant only in the process of deriving
interface identifiers from an IEEE link-layer address, and it updates
<a href="./rfc4291">RFC 4291</a> accordingly.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="http://www.rfc-editor.org/info/rfc7136">http://www.rfc-editor.org/info/rfc7136</a>.
<span class="grey">Carpenter & Jiang Standards Track [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
<a href="#section-1">1</a>. Introduction . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-2">2</a>
<a href="#section-1.1">1.1</a>. Terminology . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-2">2</a>. Problem Statement . . . . . . . . . . . . . . . . . . . . . . <a href="#page-3">3</a>
<a href="#section-3">3</a>. Usefulness of the U and G Bits . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-4">4</a>. The Role of Duplicate Address Detection . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-5">5</a>. Clarification of Specifications . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-6">6</a>. Security Considerations . . . . . . . . . . . . . . . . . . . <a href="#page-7">7</a>
<a href="#section-7">7</a>. IANA Considerations . . . . . . . . . . . . . . . . . . . . . <a href="#page-7">7</a>
<a href="#section-8">8</a>. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . <a href="#page-8">8</a>
<a href="#section-9">9</a>. References . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-8">8</a>
<a href="#section-9.1">9.1</a>. Normative References . . . . . . . . . . . . . . . . . . <a href="#page-8">8</a>
<a href="#section-9.2">9.2</a>. Informative References . . . . . . . . . . . . . . . . . <a href="#page-8">8</a>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
IPv6 unicast addresses consist of a prefix followed by an Interface
Identifier (IID). The IID is supposed to be unique on the links
reached by routing to that prefix, giving an IPv6 address that is
unique within the applicable scope (link local or global). According
to the IPv6 addressing architecture [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>], when a 64-bit IPv6
unicast IID is formed on the basis of an IEEE EUI-64 address, usually
itself expanded from a 48-bit MAC address, a particular format must
be used:
For all unicast addresses, except those that start with the binary
value 000, Interface IDs are required to be 64 bits long and to be
constructed in Modified EUI-64 format.
Thus, the specification assumes that the normal case is to transform
an Ethernet-style address into an IID, but, in practice, there are
various methods of forming such an IID.
<span class="grey">Carpenter & Jiang Standards Track [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
The Modified EUI-64 format preserves the information provided by two
particular bits in the MAC address:
o The "u/l" bit in a MAC address [<a href="#ref-IEEE802" title=""IEEE Standard for Local and Metropolitan Area Networks: Overview and Architecture"">IEEE802</a>] is set to 0 to indicate
universal scope (implying uniqueness) or to 1 to indicate local
scope (without implying uniqueness). In an IID formed from a MAC
address, this bit is simply known as the "u" bit and its value is
inverted, i.e., 1 for universal scope and 0 for local scope.
According to [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>] and [<a href="./rfc7042" title=""IANA Considerations and IETF Protocol and Documentation Usage for IEEE 802 Parameters"">RFC7042</a>], the reason for this was to
make it easier for network operators to manually configure
local-scope IIDs.
In an IID, this bit is in position 6, i.e., position 70 in the
complete IPv6 address (when counting from 0).
o The "i/g" bit in a MAC address is set to 1 to indicate group
addressing (link-layer multicast). The value of this bit is
preserved in an IID, where it is known as the "g" bit.
In an IID, this bit is in position 7, i.e., position 71 in the
complete IPv6 address (when counting from 0).
This document discusses problems observed with the "u" and "g" bits
as a result of the above requirements and the fact that various other
methods of forming an IID have been defined independently of the
method described in <a href="./rfc4291#appendix-A">Appendix A of RFC 4291</a>. It then discusses the
usefulness of these two bits and the significance of the bits in an
IID in general. Finally, it updates <a href="./rfc4291">RFC 4291</a> accordingly.
<span class="h3"><a class="selflink" id="section-1.1" href="#section-1.1">1.1</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" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>].
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Problem Statement</span>
In addition to IIDs formed from IEEE EUI-64 addresses, various new
forms of IIDs have been defined, including temporary addresses
[<a href="./rfc4941" title=""Privacy Extensions for Stateless Address Autoconfiguration in IPv6"">RFC4941</a>], Cryptographically Generated Addresses (CGAs) [<a href="./rfc3972" title=""Cryptographically Generated Addresses (CGA)"">RFC3972</a>]
[<a href="./rfc4982" title=""Support for Multiple Hash Algorithms in Cryptographically Generated Addresses (CGAs)"">RFC4982</a>], Hash-Based Addresses (HBAs) [<a href="./rfc5535" title=""Hash-Based Addresses (HBA)"">RFC5535</a>], and ISATAP
addresses [<a href="./rfc5214" title=""Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)"">RFC5214</a>]. Other methods have been proposed, such as
stable privacy addresses [<a href="#ref-IID-SLAAC">IID-SLAAC</a>] and mapped addresses for 4rd
[<a href="#ref-SOFTWR-4RD">SOFTWR-4RD</a>]. In each case, the question of how to set the "u" and
"g" bits has to be decided. For example, <a href="./rfc3972">RFC 3972</a> specifies that
they are both zero in CGAs, and <a href="./rfc4982">RFC 4982</a> describes them as if they
were reserved bits. The same applies to HBAs. On the other hand,
<a href="./rfc4941">RFC 4941</a> specifies that "u" must be zero but leaves "g" variable.
<span class="grey">Carpenter & Jiang Standards Track [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
The NAT64 addressing format [<a href="./rfc6052" title=""IPv6 Addressing of IPv4/IPv6 Translators"">RFC6052</a>] sets the whole byte containing
"u" and "g" to zero.
Another case where the "u" and "g" bits are specified is in the
Reserved IPv6 Subnet Anycast Address format [<a href="./rfc2526" title=""Reserved IPv6 Subnet Anycast Addresses"">RFC2526</a>], which states
that "for interface identifiers in EUI-64 format, the universal/local
bit in the interface identifier MUST be set to 0" (i.e., local) and
the "g" bit is required to be set to 1. However, the text neither
states nor implies any semantics for these bits in anycast addresses.
A common operational practice for well-known servers is to manually
assign a small number as the IID, in which case "u" and "g" are both
zero.
These cases illustrate that the statement quoted above from <a href="./rfc4291">RFC 4291</a>
requiring "Modified EUI-64 format" is inapplicable when applied to
forms of IID that are not in fact based on an underlying EUI-64
address. In practice, the IETF has chosen to assign some 64-bit IIDs
that have nothing to do with EUI-64.
A particular case is that of /127 prefixes for point-to-point links
between routers, as standardised by [<a href="./rfc6164" title=""Using 127-Bit IPv6 Prefixes on Inter- Router Links"">RFC6164</a>]. The addresses on
these links are undoubtedly global unicast addresses, but they do not
have a 64-bit IID. The bits in the positions named "u" and "g" in
such an IID have no special significance and their values are not
specified.
Each time a new IID format is proposed, the question arises whether
these bits have any meaning. <a href="./rfc7042#section-2.2.1">Section 2.2.1 of [RFC7042]</a> discusses
the mechanics of the bit allocations but does not explain the purpose
or usefulness of these bits in an IID. There is an IANA registry for
reserved IID values [<a href="./rfc5453" title=""Reserved IPv6 Interface Identifiers"">RFC5453</a>], but again there is no explanation of
the purpose of the "u" and "g" bits.
There was a presumption when IPv6 was designed and the IID format was
first specified that a universally unique IID might prove to be very
useful, for example to contribute to solving the multihoming problem.
Indeed, the addressing architecture [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>] states this explicitly:
The use of the universal/local bit in the Modified EUI-64 format
identifier is to allow development of future technology that can
take advantage of interface identifiers with universal scope.
However, so far, this has not proved to be the case. Also, there is
evidence from the field that MAC addresses with universal scope are
sometimes assigned to multiple MAC interfaces. There are recurrent
reports of manufacturers assigning the same MAC address to multiple
devices, and significant reuse of the same virtual MAC address is
<span class="grey">Carpenter & Jiang Standards Track [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
reported in virtual machine environments. Once transformed into IID
format (with "u" = 1), these identifiers would purport to be
universally unique but would in fact be ambiguous. This has no known
harmful effect as long as the replicated MAC addresses and IIDs are
used on different layer 2 links. If they are used on the same link,
of course there will be a problem, very likely interfering with
link-layer transmission. If not, the problem will be detected by
duplicate address detection [<a href="./rfc4862" title=""IPv6 Stateless Address Autoconfiguration"">RFC4862</a>] [<a href="./rfc6775" title=""Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)"">RFC6775</a>], but such an error
can usually only be resolved by human intervention.
The conclusion from this is that the "u" bit is not a reliable
indicator of universal uniqueness.
We note that Identifier-Locator Network Protocol (ILNP), a
multihoming solution that might be expected to benefit from
universally unique IIDs in modified EUI-64 format, does not in fact
rely on them. ILNP uses its own format defined as a Node Identifier
[<a href="./rfc6741" title=""Identifier-Locator Network Protocol (ILNP) Engineering Considerations"">RFC6741</a>]. ILNP has the constraint that a given Node Identifier must
be unique within the context of a given Locator (i.e., within a
single given IPv6 subnetwork). As we have just shown, the state of
the "u" bit does not in any way guarantee such uniqueness, but
duplicate address detection is available.
Thus, we can conclude that the value of the "u" bit in IIDs has no
particular meaning. In the case of an IID created from a MAC address
according to <a href="./rfc4291">RFC 4291</a>, its value is determined by the MAC address,
but that is all.
An IPv6 IID should not be created from a MAC group address, so the
"g" bit will normally be zero. But, this value also has no
particular meaning. Additionally, the "u" and the "g" bits are both
meaningless in the format of an IPv6 multicast group ID [<a href="./rfc3306" title=""Unicast-Prefix-based IPv6 Multicast Addresses"">RFC3306</a>]
[<a href="./rfc3307" title=""Allocation Guidelines for IPv6 Multicast Addresses"">RFC3307</a>].
None of the above implies that there is a problem with using the "u"
and "g" bits in MAC addresses as part of the process of generating
IIDs from MAC addresses, or with specifying their values in other
methods of generating IIDs. What it does imply is that after an IID
is generated by any method, no reliable deductions can be made from
the state of the "u" and "g" bits; in other words, these bits have no
useful semantics in an IID.
Once this is recognised, we can avoid the problematic confusion
caused by these bits each time that a new form of IID is proposed.
<span class="grey">Carpenter & Jiang Standards Track [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Usefulness of the U and G Bits</span>
Given that the "u" and "g" bits do not have a reliable meaning in an
IID, it is relevant to consider what usefulness they do have.
If an IID is known or guessed to have been created according to
[<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>], it could be transformed back into a MAC address. This can
be very helpful during operational fault diagnosis. For that reason,
mapping the IEEE "u" and "g" bits into the IID has operational
usefulness. However, it should be stressed that an IID with "u" = 1
and "g" = 0 might not be formed from a MAC address; on the contrary,
it might equally result from another method. With other methods,
there is no reverse transformation available.
Given that the values of the "u" and "g" bits in an IID have no
particular meaning, new methods of IID formation are at liberty to
use them as they wish, for example, as additional pseudo-random bits
to reduce the chances of duplicate IIDs.
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. The Role of Duplicate Address Detection</span>
As mentioned above, Duplicate Address Detection (DAD) [<a href="./rfc4862" title=""IPv6 Stateless Address Autoconfiguration"">RFC4862</a>] is
able to detect any case where a collision of two IIDs on the same
link leads to a duplicated IPv6 address. The scope of DAD may be
extended to a set of links by a DAD proxy [<a href="./rfc6957" title=""Duplicate Address Detection Proxy"">RFC6957</a>] or by Neighbor
Discovery Optimization [<a href="./rfc6775" title=""Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)"">RFC6775</a>]. Since DAD is mandatory for all
nodes, there will be almost no case in which an IID collision,
however unlikely it may be, is not detected. It is out of scope of
most existing specifications to define the recovery action after a
DAD failure, which is an implementation issue. If a manually created
IID, or an IID derived from a MAC address according to <a href="./rfc4291">RFC 4291</a>,
leads to a DAD failure, human intervention will most likely be
required. However, as mentioned above, some methods of IID formation
might produce IID values with "u" = 1 and "g" = 0 that are not based
on a MAC address. With very low probability, such a value might
collide with an IID based on a MAC address.
As stated in <a href="./rfc4862">RFC 4862</a>:
On the other hand, if the duplicate link-local address is not
formed from an interface identifier based on the hardware address,
which is supposed to be uniquely assigned, IP operation on the
interface MAY be continued.
Continued operation is only possible if a new IID is created. The
best procedure to follow for this will depend on the IID formation
method in use. For example, if an IID is formed by a pseudo-random
process, that process could simply be repeated.
<span class="grey">Carpenter & Jiang Standards Track [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Clarification of Specifications</span>
This section describes clarifications to the IPv6 specifications that
result from the above discussion.
The EUI-64 to IID transformation defined in the IPv6 addressing
architecture [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>] MUST be used for all cases where an IPv6 IID
is derived from an IEEE MAC or EUI-64 address. With any other form
of link-layer address, an equivalent transformation SHOULD be used.
Specifications of other forms of 64-bit IIDs MUST specify how all 64
bits are set, but a generic semantic meaning for the "u" and "g" bits
MUST NOT be defined. However, the method of generating IIDs for
specific link types MAY define some local significance for certain
bits.
In all cases, the bits in an IID have no generic semantics; in other
words, they have opaque values. In fact, the whole IID value MUST be
viewed as an opaque bit string by third parties, except possibly in
the local context.
The following statement in <a href="#section-2.5.1">Section 2.5.1</a> of the IPv6 addressing
architecture [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>]:
For all unicast addresses, except those that start with the binary
value 000, Interface IDs are required to be 64 bits long and to be
constructed in Modified EUI-64 format.
is replaced by:
For all unicast addresses, except those that start with the binary
value 000, Interface IDs are required to be 64 bits long. If
derived from an IEEE MAC-layer address, they must be constructed
in Modified EUI-64 format.
The following statement in <a href="#section-2.5.1">Section 2.5.1</a> of the IPv6 addressing
architecture [<a href="./rfc4291" title=""IP Version 6 Addressing Architecture"">RFC4291</a>] is obsoleted:
The use of the universal/local bit in the Modified EUI-64 format
identifier is to allow development of future technology that can
take advantage of interface identifiers with universal scope.
As far as is known, no existing implementation will be affected by
these changes. The benefit is that future design discussions are
simplified.
<span class="grey">Carpenter & Jiang Standards Track [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. Security Considerations</span>
No new security exposures or issues are raised by this document.
In some contexts, unpredictable IID values are considered beneficial
to enhance privacy and defeat scanning attacks. The recognition that
the IID value should be regarded as an opaque bit string is
consistent with methods of IID formation that result in
unpredictable, pseudo-random values.
<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. IANA Considerations</span>
This document requests no immediate action by IANA. However, the
following should be noted when considering any future proposed
addition to the registry of reserved IID values, which requires
Standards Action [<a href="./rfc5226" title="">RFC5226</a>] according to [<a href="./rfc5453" title=""Reserved IPv6 Interface Identifiers"">RFC5453</a>].
Full deployment of a new reserved IID value would require updates to
IID generation code in every deployed IPv6 stack, so the technical
justification for such a Standards Action would need to be extremely
strong.
The preceding sentence and a reference to this document have been
added to the "Reserved IPv6 Interface Identifiers" registry.
<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. Acknowledgements</span>
Valuable comments were received from Ran Atkinson, Remi Despres,
Ralph Droms, Fernando Gont, Eric Gray, Brian Haberman, Joel Halpern,
Bob Hinden, Christian Huitema, Ray Hunter, Tatuya Jinmei, Roger
Jorgensen, Mark Smith, Bernie Volz, and other participants in the
6MAN working group.
Brian Carpenter was a visitor at the Computer Laboratory, Cambridge
University during part of this work.
<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>. References</span>
<span class="h3"><a class="selflink" id="section-9.1" href="#section-9.1">9.1</a>. Normative References</span>
[<a id="ref-RFC2119">RFC2119</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-RFC4291">RFC4291</a>] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", <a href="./rfc4291">RFC 4291</a>, February 2006.
[<a id="ref-RFC4862">RFC4862</a>] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", <a href="./rfc4862">RFC 4862</a>, September 2007.
<span class="grey">Carpenter & Jiang Standards Track [Page 8]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-9" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
[<a id="ref-RFC5453">RFC5453</a>] Krishnan, S., "Reserved IPv6 Interface Identifiers", <a href="./rfc5453">RFC</a>
<a href="./rfc5453">5453</a>, February 2009.
[<a id="ref-RFC7042">RFC7042</a>] Eastlake, D. and J. Abley, "IANA Considerations and IETF
Protocol and Documentation Usage for IEEE 802 Parameters",
<a href="https://www.rfc-editor.org/bcp/bcp141">BCP 141</a>, <a href="./rfc7042">RFC 7042</a>, October 2013.
<span class="h3"><a class="selflink" id="section-9.2" href="#section-9.2">9.2</a>. Informative References</span>
[<a id="ref-IEEE802">IEEE802</a>] "IEEE Standard for Local and Metropolitan Area Networks:
Overview and Architecture", IEEE Std 802-2001 (R2007),
2007.
[<a id="ref-IID-SLAAC">IID-SLAAC</a>]
Gont, F., "A method for Generating Stable Privacy-Enhanced
Addresses with IPv6 Stateless Address Autoconfiguration
(SLAAC)", Work in Progress, March 2012.
[<a id="ref-RFC2526">RFC2526</a>] Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast
Addresses", <a href="./rfc2526">RFC 2526</a>, March 1999.
[<a id="ref-RFC3306">RFC3306</a>] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", <a href="./rfc3306">RFC 3306</a>, August 2002.
[<a id="ref-RFC3307">RFC3307</a>] Haberman, B., "Allocation Guidelines for IPv6 Multicast
Addresses", <a href="./rfc3307">RFC 3307</a>, August 2002.
[<a id="ref-RFC3972">RFC3972</a>] Aura, T., "Cryptographically Generated Addresses (CGA)",
<a href="./rfc3972">RFC 3972</a>, March 2005.
[<a id="ref-RFC4941">RFC4941</a>] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", <a href="./rfc4941">RFC 4941</a>, September 2007.
[<a id="ref-RFC4982">RFC4982</a>] Bagnulo, M. and J. Arkko, "Support for Multiple Hash
Algorithms in Cryptographically Generated Addresses
(CGAs)", <a href="./rfc4982">RFC 4982</a>, July 2007.
[<a id="ref-RFC5214">RFC5214</a>] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
Automatic Tunnel Addressing Protocol (ISATAP)", <a href="./rfc5214">RFC 5214</a>,
March 2008.
[<a id="ref-RFC5226">RFC5226</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="./rfc5226">RFC 5226</a>,
May 2008.
[<a id="ref-RFC5535">RFC5535</a>] Bagnulo, M., "Hash-Based Addresses (HBA)", <a href="./rfc5535">RFC 5535</a>, June
2009.
<span class="grey">Carpenter & Jiang Standards Track [Page 9]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-10" ></span>
<span class="grey"><a href="./rfc7136">RFC 7136</a> IPv6 IID Significance February 2014</span>
[<a id="ref-RFC6052">RFC6052</a>] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", <a href="./rfc6052">RFC 6052</a>,
October 2010.
[<a id="ref-RFC6164">RFC6164</a>] Kohno, M., Nitzan, B., Bush, R., Matsuzaki, Y., Colitti,
L., and T. Narten, "Using 127-Bit IPv6 Prefixes on Inter-
Router Links", <a href="./rfc6164">RFC 6164</a>, April 2011.
[<a id="ref-RFC6741">RFC6741</a>] Atkinson,, RJ., "Identifier-Locator Network Protocol
(ILNP) Engineering Considerations", <a href="./rfc6741">RFC 6741</a>, November
2012.
[<a id="ref-RFC6775">RFC6775</a>] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann,
"Neighbor Discovery Optimization for IPv6 over Low-Power
Wireless Personal Area Networks (6LoWPANs)", <a href="./rfc6775">RFC 6775</a>,
November 2012.
[<a id="ref-RFC6957">RFC6957</a>] Costa, F., Combes, J-M., Pougnard, X., and H. Li,
"Duplicate Address Detection Proxy", <a href="./rfc6957">RFC 6957</a>, June 2013.
[<a id="ref-SOFTWR-4RD">SOFTWR-4RD</a>]
Despres, R., Jiang, S., Penno, R., Lee, Y., Chen, G., and
M. Chen, "IPv4 Residual Deployment via IPv6 - a Stateless
Solution (4rd)", Work in Progress, October 2013.
Authors' Addresses
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
EMail: brian.e.carpenter@gmail.com
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing 100095
P.R. China
EMail: jiangsheng@huawei.com
Carpenter & Jiang Standards Track [Page 10]
</pre>
|
