Internet DRAFT - draft-pioxfolks-6man-pio-exclusive-bit
draft-pioxfolks-6man-pio-exclusive-bit
Internet Engineering Task Force E. Kline
Internet-Draft Google Japan KK
Updates: 4861,6275 (if approved) M. Abrahamsson
Intended status: Experimental T-Systems Nordic
Expires: September 28, 2017 March 27, 2017
IPv6 Router Advertisement Prefix Information Option eXclusive Flag
draft-pioxfolks-6man-pio-exclusive-bit-02
Abstract
This document defines a new control bit in the IPv6 RA PIO flags
octet that indicates that the node receiving this RA is the exclusive
receiver of all traffic destined to any address within that prefix.
Termed the eXclusive flag (or "X flag"), nodes that recognize this
can perform some optimizations to save time and traffic (e.g. disable
ND and DAD for addresses within this prefix) and more immediately
pursue the benefits of being provided multiple addresses (vis.
[RFC7934] section 3). Additionally, network infrastructure nodes
(routers, switches) can benefit by minimizing the number of {link
layer, IP} address pairs required to offer network connectivity (vis.
[RFC7934] section 9.3).
Use of the X flag is backward compatible with existing IPv6 standards
compliant implementations.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 28, 2017.
Copyright Notice
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Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Efficiency improvements . . . . . . . . . . . . . . . . . 4
2.2. New architectural possibilities . . . . . . . . . . . . . 4
3. Applicability statement . . . . . . . . . . . . . . . . . . . 5
4. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Requirements Language . . . . . . . . . . . . . . . . . . 6
4.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 6
4.2.1. PIO-X . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.2. PIO-X RA . . . . . . . . . . . . . . . . . . . . . . 6
4.2.3. Host . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Updated Prefix Information Option . . . . . . . . . . . . . . 6
5.1. Updated format description . . . . . . . . . . . . . . . 6
5.2. Receiver processing . . . . . . . . . . . . . . . . . . . 7
5.2.1. PIO R flag . . . . . . . . . . . . . . . . . . . . . 7
5.2.2. (Re)Interpretation of other flags . . . . . . . . . . 7
5.2.2.1. PIO L flag . . . . . . . . . . . . . . . . . . . 8
5.2.2.2. PIO A flag . . . . . . . . . . . . . . . . . . . 8
5.3. Sender requirements . . . . . . . . . . . . . . . . . . . 8
5.4. Comparison with DHCPv6 PD . . . . . . . . . . . . . . . . 9
6. Host behavior . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. PIO-X processing . . . . . . . . . . . . . . . . . . . . 9
6.2. Neighbor Discovery implications . . . . . . . . . . . . . 9
6.2.1. Duplicate Address Detection (DAD) . . . . . . . . . . 9
6.2.2. Router Solicitations (RSes) . . . . . . . . . . . . . 10
6.3. Link-local address behavior . . . . . . . . . . . . . . . 10
6.4. Source address selection . . . . . . . . . . . . . . . . 10
6.5. Next hop router selection . . . . . . . . . . . . . . . . 11
6.6. Implications for Detecting Network Attachment . . . . . . 11
6.7. Additional guidance . . . . . . . . . . . . . . . . . . . 11
7. Router behavior . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. PIO-X RA destination address . . . . . . . . . . . . . . 11
7.2. Detecting hosts to send PIO-X RAs to . . . . . . . . . . 12
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7.3. Binding table requirements . . . . . . . . . . . . . . . 12
7.4. Preparations before sending a PIO-X RA . . . . . . . . . 13
7.5. Implementation considerations . . . . . . . . . . . . . . 13
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
10. Security Considerations . . . . . . . . . . . . . . . . . . . 13
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
This document defines a new control flag in the Internet Protocol
version 6 (IPv6) Router Advertisement (RA) Prefix Information Option
(PIO) flags octet that indicates that the node receiving this RA is
the exclusive receiver of all traffic destined to any address with
that prefix. Subject to the lifetime constraints within the PIO, the
receiving node effectively has exclusive use of the prefix, and will
be the next hop destination for the sending router, and possibly
other routers, for all traffic destined toward the prefix.
Termed the eXclusive flag (or "X flag"), nodes that recognize this
can perform some optimizations to save time and traffic (e.g. disable
Neighbor Discovery (ND) and Duplicate Address Detection (DAD) for
addresses within this prefix) and more immediately pursue the
benefits of being provided multiple addresses (vis. [RFC7934]
section 3).
Additionally, network infrastructure nodes (routers, switches) can
benefit by minimizing the number of {link layer, IP} address pairs
required to offer network connectivity (vis. [RFC7934] section 9.3).
A router, for example, need not create any {link layer, IP} address
pair entries for IP address within a proffered exclusive-use prefix--
it can reliably forward all traffic to the network node to which it
advertised the prefix. This solves one potential link layer state
exhaustion problem, i.e excessive number of {link layer, IP address
pairs}, using IP layer forwarding.
Use of the X flag is backward compatible with existing IPv6 standards
compliant implementations. [RFC4861]-compliant nodes that do not
understand the X flag are not negatively impacted. They must ignore
it, and can process the PIO under existing standards, making use of
the information exactly as if the X flag were not set.
2. Motivation
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This work is motivated by the pursuit of two categories of benefits:
modest host and network side improvements in efficiency, and support
for new deployment architectures and address space use models.
2.1. Efficiency improvements
If a host knows it has exclusive use of a prefix it can perform some
optimizations to save time and traffic. It can avoid ND on the
receiving interface for addresses within these prefixes. Network
interfaces can even drop Neighbor Solicitations for these addresses
on the receiving interface to save power by not waking up more power-
hungry CPUs.
Additionally, a host can save time by not performing DAD for
addresses within an exclusive-use prefix on the receiving interface.
A host that wanted, for example, to use 2**64 unique IPv6 source
addresses for DNS queries in order to improve resilience against
forged answers (as recommended in section 9.2 of [1]), could do so
without delaying each query from a newly formed address. A node
could in theory implement the same strategy using Optimistic
Duplicate Address Detection [2], but it could be very unfriendly to
the network infrastructure (in terms of {link-layer, IP address} pair
state) to do so without this kind of explicit signal.
A host that recognizes the X flag might perform other traffic-saving
optimizations, like not attempt Multicast DNS in some cases, or avoid
trying to register addresses with sleep proxies. Being the only host
on this link these may be of little benefit.
2.2. New architectural possibilities
There are several initiatives that propose network side practices
that provide customer isolation, enhanced operational scalability,
power efficiency, security and other benefits in IPv6 network
deployments. Some of these involve isolating a host (or RA accepting
client node) so that the host is the only node to receive a specific
prefix, including
o DHCPv6 Prefix Delegation to hosts ([3]), and
o advertising a unique prefix per host via unique RAs. ([4]).
Some architectures further isolate the host layers below IPv6, for
improved client node security.
Regardless of the specific level of isolation, the host can best make
choices about its use of a prefix exclusively forwarded to itself if
the host can be informed of the exclusivity. (In the case of a
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DHCPv6 Prefix Delegation the prefix can be assumed to be of exclusive
use by the requesting node, in accordance with the model in
[RFC3633].) An implementation can, for example, safely "bind to an
IPv6 subnet" in the style of [5], or start 64sharing [6] (given a
prefix of sufficient size).
This memo documents an additional flag in the IPv6 RA PIO that makes
this information explicit to receiving node.
3. Applicability statement
Use of the X flag in PIOs is only applicable to networks where the
architecture (i.e. serving infrastructure like routers, link-layer
equipment, et cetera) can collectively guarantee the following
criteria are met:
1. an RA containing a PIO with the X flag set MUST be delivered to
one and only target node (host) such that no two nodes can
reasonably expect exclusive access to the same prefix at the same
time
2. any router advertising an RA containing a PIO with the X flag set
SHOULD be notified quickly when a node leaves the network
The first criterion ensures that the same exclusive use prefix is not
advertised to more than one host at a time (and hence no longer
"exclusive"). This implies that an allocated exclusive-use prefix
must be tracked by the issuing router for at least the minimum of (a)
the lifetime of the recipient node's continuous attachment to the
network and (b) the lifetime of the prefix itself in the PIO, if not
longer.
The second criterion aims to help the prefix allocation
infrastructure reclaim unused prefixes quickly while also helping
routers drop (possibly with appropriate ICMPv6 errors) traffic that
can no longer be delivered.
It is expected that in practice this primarily describes networks
where the IPv6 infrastructure and the link-layer have a tight
integration. All point-to-point links meet these criteria (e.g.
PPPoE and VPNs), as does the 3GPP architecture [RFC7066] and some
IEEE 802.11 deployment architectures ([7]).
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4. Terminology
4.1. Requirements Language
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 RFC 2119 [RFC2119].
4.2. Abbreviations
Throughout this document the following terminology is used purely for
the sake of brevity.
4.2.1. PIO-X
The term "PIO-X" is used to refer to a Prefix Information Option
(PIO) that has the X flag set.
4.2.2. PIO-X RA
The phrase "PIO-X RA" is used to refer to an IPv6 Router
Advertisement (RA) that contains one or more PIO-X entries (the same
RA may also contain one or more PIOs without the X flag set).
4.2.3. Host
The term "host" may be used interchangeably throughout this document
to mean a network node receiving and processing an RA. The receiving
node may itself be a router, or may temporarily become one by routing
all or a portion of an exclusive use prefix.
5. Updated Prefix Information Option
This document updates the Prefix Information Option specification in
RFC 4861 [8] section 4.6.2 and RFC 6275 [9] section 7.2 with the
definition of a flag from the former Reserved1 field as follows.
5.1. Updated format description
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Prefix Length |L|A|R|X| Rsrvd1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Valid Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preferred Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fields:
X The eXclusive use indicator flag, defined by this document.
When set, the receiving node can be assured that all traffic
destined to any address within the specified Prefix will be
forwarded to itself by, at a minimum, the router from which
the encapsulating RA was received, but possibly other routers
as well.
When not set, the receiving node MUST NOT make any
assumptions of exclusive use of the specified Prefix, i.e.
processing is unchanged from previous standards behavior.
Rsrvd1 Retains the same meaning as Reserved1 from [10] section
4.6.2.
All Retain their same meaning from [11] section 4.6.2.
other
fields
5.2. Receiver processing
Nodes compliant with this specification perform the following
additional processing of RAs and PIO-X options when a PIO-X option is
present.
5.2.1. PIO R flag
If the R flag is set then the X flag MUST be ignored. The R flag
indicates that the PIO includes an address the router has selected
for itself from the prefix. Logically, the prefix cannot exclusively
be used by the receiving node if the router has allocated any
addresses for itself from the prefix.
5.2.2. (Re)Interpretation of other flags
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Nodes compliant with this specification, i.e. those that understand
the X-flag, MUST, when the X-flag is set, ignore the actual values of
the L and A flags and instead interpret them as follows:
o interpret the L flag as if it were 0 (L=0)
o interpret the A flag as it it were 1 (A=1)
The rationale for this is as follows.
5.2.2.1. PIO L flag
Because a PIO-X aware node will know that it has exclusive use of a
prefix with non-zero valid lifetime, the prefix itself cannot be
considered to be on-link with respect to the link on which the PIO-X
RA was received.
Note that a given address from within the prefix may be considered
on-link according to the definition in [12] section 4, item 1, should
the receiving node chose to configure that address on said link, but
this is in no way synonymous with the entire prefix being considered
on-link.
5.2.2.2. PIO A flag
Because a PIO-X aware node will know that it has exclusive use of a
prefix with non-zero valid lifetime, autoconfiguration of addresses
according to any desired scheme, e.g. [13], [14], et cetera, is
implicit in the setting of the X flag.
Accordingly, the A flag can be interpreted as having been set, should
the host choose to apply standard address generation schemes that
require the flag to be set. It is free to assign any address formed
from an exclusive prefix to any available interface; it is not
required to configure the address on the link over which the PIO-X RA
was received (i.e. it is under no obligation to form addresses such
that they would be classified as on-link (according to the definition
in [15] section 4, item 1).
5.3. Sender requirements
When a router transmits an RA containing one or more PIO-X options it
SHOULD unicast the PIO-X RA to its intended recipient at the IPv6
layer and, if applicable, at the link-layer.
It is RECOMMENDED that a PIO with the X-flag set also have the PIO
flags L=0 and A=1 explicitly configured, for backward compatibility
(i.e. use by non X-flag aware nodes).
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A router transmitting a PIO-X RA MUST NOT configure for itself any
address from with the PIO-X prefix. (If it did, the prefix would
logically no longer be of exclusive use for the receiving node.)
5.4. Comparison with DHCPv6 PD
There exists a key difference in semantics between PIO-X and DHCPv6
PD: with PIO-X the network keeps the client refreshed with its prefix
whereas with DHCPv6 PD the client is responsible for refreshing its
prefix from the server. This is one reason it is important for the
data link layer to be able to quickly inform routers of client
detachment.
Another difference is that [16] section 12.1 states:
... the requesting router MUST
NOT assign any delegated prefixes or subnets from the delegated
prefix(es) to the link through which it received the DHCP message
from the delegating router.
In contrast, a node receiving a PIO-X RA is explicitly free to treat
the entire prefix as on-link with respect to the interface via which
it was received.
6. Host behavior
TODO: This section needs some work.
6.1. PIO-X processing
A receiving node compliant with this document processes an RA with a
PIO entry with the X flag set according the requirements in previous
standards documents (chiefly [17] section 6.3.4) subject to the
additional requirements documented in Section 5.2.
6.2. Neighbor Discovery implications
6.2.1. Duplicate Address Detection (DAD)
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Whatever use the host makes of the exclusive prefix during its valid
lifetime, it SHOULD NOT perform Duplicate Address Detection ("DAD",
[18] section 5.4) on any address it configures from within the prefix
if that address is configured on either the interface over which the
PIO-X RA was received or on a loopback interface. Note that this
does not absolve the host from performing DAD in all scenarios; if,
for example, the host uses the prefix for 64sharing [19] it MUST at a
minimum defend via DAD any addresses it has configured for itself as
documented in Requirement 2 of [20] section 3.
6.2.2. Router Solicitations (RSes)
Routers announcing PIO-X RAs do so via IPv6 unicast to the intended
receiving node and may note the IPv6 unicast destination address of
an RS as the next hop for the exclusive prefix. As such, hosts
compliant with this SHOULD NOT use the unspecified address (::) when
sending RSes; they SHOULD prefer issuing Router Solicitations from a
link-local address.
It is possible for a node to receive multiple RAs with a mix of
exclusive and non-exclusive PIOs and even non-zero and zero default
router lifetimes. While it is not possible for a host (receiving
node) to be sure it has received all the RA information available to
it, hosts compliant with this specification SHOULD implement Packet-
Loss Resiliency for Router Solicitations [RFC7559] so that the host
continues to transmit Router Solicitations at least until an RA with
a non-zero default router lifetime has been seen.
6.3. Link-local address behavior
Routers announcing PIO-X RAs may record the source (link-local)
address of an RS as the next hop for the exclusive prefix. A node
compliant with this specification MUST continue to respond to
Neighbor Solicitations for the source address used to send RSes
(alternatively: the destination address of unicast PIO-X RAs
received). Hosts that deprecate or even remove this address may
experience a loss of connectivity.
6.4. Source address selection
No change to existing source address selection behavior is required
or specified by this document.
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6.5. Next hop router selection
No change to existing next hop router selection behavior is required
or specified by this document.
6.6. Implications for Detecting Network Attachment
TODO: Describe implications for Detecting Network Attachment in IPv6
[21] (DNAv6). Probably the best that can be done is (a) no change to
RFC6059 coupled with (b) a host MAY send a test packet (e.g. ICMPv6
Echo Request) with a source and destination address from within the
PIO-X prefix to the PIO-X RA issuing router and verify the packet is
delivered back to itself. Consistent failure to receive such traffic
MAY be considered a signal that the exclusive prefix should no longer
be used by the host.
6.7. Additional guidance
The intent of networks that use PIO-X RAs is not to enable
sophisticated routing architectures that could be far better handled
by an actual routing protocol but rather to propagate a prefix's
exclusive use information to enable the receiving node to make better
use of the available addresses. As such:
A PIO-X receiving node SHOULD NOT issue ICMPv6 Redirects
([RFC4861] section 4.5) for any address within an exclusive use
prefix via the link over which the PIO-X RA was received.
Redirecting portions of exclusive prefixes to other "upstream" on-
link nodes is not a supported configuration.
A PIO-X receiving node SHOULD NOT transmit RAs with any subset of
its exclusive prefixes via the same interface through which the
exclusive prefix was learned.
7. Router behavior
TODO: This section needs some work.
7.1. PIO-X RA destination address
Since the host will not perform DAD for addresses within prefix
announced via PIO-X, it's very important that only a single host
receives the PIO-X RA. Therefore, the router MUST only include PIO-X
in RAs that are sent using unicast RAs to destination unicast link-
layer address and IPv6 link-local unicast address for a specific
host. For point-to-point media without link-layer addresses or where
there is guaranteed to only be single host that will receive the
PIO-X RA (e.g. as enforced by link layer mechanisms), the router MAY
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send PIO-X RA with multicast destination IPv6 address. Under all
circumstances the router MUST maintain a binding table of state
information as discussed in Section 7.3.
7.2. Detecting hosts to send PIO-X RAs to
When the host starts using a network connection it normally sends out
an RS (Router Solicitation) packet. This is one way for the router
to detect that a new host is connected to the network and detects its
link-local address. If the router is configured to use PIO-X, it can
now perform necessary processing/configuration and then send the
PIO-X RA.
For some networks, the host information regarding link-layer and
link-local address might be available through other mechanism(s).
Examples of this are PPP, 802.1x and 3GPP mobile networks. In that
case this information MAY be used instead of relying on the host to
send RS. It is however RECOMMENDED that these networks also provide
indication whether the host is no longer connected to the network so
that the router can invalidate the prefix binding prior to binding
expiration (timeout).
7.3. Binding table requirements
Routers transmitting PIO-X RAs have state maintenance and operational
requirements similar to delegating routers in networks where DHCPv6
Prefix Delegation [RFC3633] is used. The state maintained is
describe here in terms of a conceptual binding table.
R1 The router SHOULD keep track of which PIO-X prefix has been
issued to each node.
R2 The router SHOULD keep the binding between prefix and link-local
address for the advertised valid lifetime, plus some
operationally determined delay prior to reissuing a prefix
("grace period"), of the prefix.
R3 The router MUST monitor the reachability of each node in the
binding table via Neighbor Unreachability Detection ("NUD", [22]
section 7.3) or an equivalent link-layer mechanism.
R4 The binding SHOULD be considered refreshed every time a periodic
PIO-X RA is sent to a node.
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R5 If the router is informed by some other mechanism (link-layer
indication for instance) that a node is no longer connected to
the link, it MAY immediately invalidate the prefix binding.
(DISCUSS: Is this the correct approach? Do we want to point to
some definition somewhere else?)
7.4. Preparations before sending a PIO-X RA
When the router intends to send a PIO-X RA, it SHOULD before sending
the PIO-X RA, complete any and all necessary processing for the host
to start using the PIO-X prefix to communicate through the router to
other networks. This is so that the host can start using PIO-X based
addresses without delay or error after receipt of the PIO-X RA.
7.5. Implementation considerations
TODO: Out of scope things that are worth careful consideration
include...
Routers SHOULD NOT announce the same prefix to two different nodes
within the valid lifetime of the earlier of the two PIO-X
announcements.
A link may operate in a mode where routers announce RAs to all nodes,
possibly with non-exclusive PIO data, and non-zero default router
lifetimes. Separately, one or more other nodes on the link may
announce exclusive PIO information to nodes along with zero default
router lifetimes. Except in the presence of a non-expired more
specific route, e.g. learning from an [23] Route Information Option
(RIO), the receiving node should send exclusive use prefix originated
or forwarded traffic destined off-link through routers with non-zero
default router lifetimes.
8. Acknowledgements
9. IANA Considerations
This memo contains no requests of IANA.
10. Security Considerations
This document fundamentally introduces no new protocol or behavior
substantively different from existing behavior on a link which
guarantees a unique /64 prefix to every attached host. It only
describes a mechanism to convey that topological reality, allowing
the host to make certain optimizations as well as share the exclusive
prefix as it sees fit with other nodes according to its capabilities
and policies.
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11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, DOI 10.17487/
RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <http://www.rfc-editor.org/info/rfc6275>.
[RFC7559] Krishnan, S., Anipko, D., and D. Thaler, "Packet-Loss
Resiliency for Router Solicitations", RFC 7559, DOI
10.17487/RFC7559, May 2015,
<http://www.rfc-editor.org/info/rfc7559>.
11.2. Informative References
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
DOI 10.17487/RFC3633, December 2003,
<http://www.rfc-editor.org/info/rfc3633>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <http://www.rfc-editor.org/info/rfc4191>.
[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
<http://www.rfc-editor.org/info/rfc4429>.
[RFC5452] Hubert, A. and R. van Mook, "Measures for Making DNS More
Resilient against Forged Answers", RFC 5452, DOI 10.17487/
RFC5452, January 2009,
<http://www.rfc-editor.org/info/rfc5452>.
[RFC7066] Korhonen, J., Ed., Arkko, J., Ed., Savolainen, T., and S.
Krishnan, "IPv6 for Third Generation Partnership Project
Kline & Abrahamsson Expires September 28, 2017 [Page 14]
Internet-Draft IPv6 RA PIO eXclusive Flag March 2017
(3GPP) Cellular Hosts", RFC 7066, DOI 10.17487/RFC7066,
November 2013, <http://www.rfc-editor.org/info/rfc7066>.
[RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi,
"Host Address Availability Recommendations", BCP 204, RFC
7934, DOI 10.17487/RFC7934, July 2016,
<http://www.rfc-editor.org/info/rfc7934>.
Authors' Addresses
Erik Kline
Google Japan KK
6-10-1 Roppongi
Mori Tower, 44th floor
Minato, Tokyo 106-6126
JP
Email: ek@google.com
Mikael Abrahamsson
T-Systems Nordic
Kistagangen 26
Stockholm
SE
Email: Mikael.Abrahamsson@t-systems.se
Kline & Abrahamsson Expires September 28, 2017 [Page 15]
