draft-ietf-6man-impatient-nud-07.txt   rfc7048.txt 
6MAN WG E. Nordmark Internet Engineering Task Force (IETF) E. Nordmark
Internet-Draft Arista Networks Request for Comments: 7048 Arista Networks
Updates: 4861 (if approved) I. Gashinsky Updates: 4861 I. Gashinsky
Intended status: Standards Track Yahoo! Category: Standards Track Yahoo!
Expires: April 24, 2014 October 21, 2013 ISSN: 2070-1721 January 2014
Neighbor Unreachability Detection is too impatient Neighbor Unreachability Detection Is Too Impatient
draft-ietf-6man-impatient-nud-07.txt
Abstract Abstract
IPv6 Neighbor Discovery includes Neighbor Unreachability Detection. IPv6 Neighbor Discovery includes Neighbor Unreachability Detection.
That function is very useful when a host has an alternative neighbor, That function is very useful when a host has an alternative neighbor
for instance when there are multiple default routers, since it allows -- for instance, when there are multiple default routers -- since it
the host to switch to the alternative neighbor in short time. This allows the host to switch to the alternative neighbor in a short
time is 3 seconds after the node starts probing by default. However, time. By default, this time is 3 seconds after the node starts
if there are no alternative neighbors, this is far too impatient. probing. However, if there are no alternative neighbors, this
This document specifies relaxed rules for Neighbor Discovery timeout behavior is far too impatient. This document specifies
retransmissions that allow an implementation to choose different relaxed rules for Neighbor Discovery retransmissions that allow an
timeout behavior based on whether or not there are alternative implementation to choose different timeout behavior based on whether
neighbors. This document updates RFC 4861. or not there are alternative neighbors. This document updates RFC
4861.
Status of this Memo
This Internet-Draft is submitted in full conformance with the Status of This Memo
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This is an Internet Standards Track document.
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on April 24, 2014. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7048.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction ....................................................2
2. Definition Of Terms . . . . . . . . . . . . . . . . . . . . . . 4 2. Definition of Terms .............................................3
3. Protocol Updates . . . . . . . . . . . . . . . . . . . . . . . 4 3. Protocol Updates ................................................3
4. Example Algorithm . . . . . . . . . . . . . . . . . . . . . . . 6 4. Example Algorithm ...............................................6
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 5. Acknowledgements ................................................7
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations .........................................8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 7. References ......................................................8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References .......................................8
8.1. Normative References . . . . . . . . . . . . . . . . . . . 8 7.2. Informative References .....................................8
8.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
IPv6 Neighbor Discovery [RFC4861] includes Neighbor Unreachability IPv6 Neighbor Discovery [RFC4861] includes Neighbor Unreachability
Detection (NUD), which detects when a neighbor is no longer Detection (NUD), which detects when a neighbor is no longer
reachable. The timeouts specified for NUD are very short (by default reachable. The timeouts specified for NUD are very short (by
three transmissions spaced one second apart). These short timeouts default, three transmissions spaced one second apart). These short
can be appropriate when there are alternative neighbors to which the timeouts can be appropriate when there are alternative neighbors to
packets can be sent. For example, if a host has multiple default which the packets can be sent -- for example, if a host has multiple
routers in its Default Router List or if the host has a Neighbor default routers in its Default Router List or if the host has a
Cache Entry (NCE) created by a Redirect message. In those cases, Neighbor Cache Entry (NCE) created by a Redirect message. In those
when NUD fails, the host will try the alternative neighbor by redoing cases, when NUD fails, the host will try the alternative neighbor by
next-hop selection. That implies picking the next router in the redoing the next-hop selection. That implies picking the next router
Default Router List or discarding the redirect, respectively. in the Default Router List or discarding the NCE created by a
Redirect message, respectively.
The timeouts specified in [RFC4861] were chosen to be short in order The timeouts specified in [RFC4861] were chosen to be short in order
to optimize for the scenarios where alternative neighbors are to optimize scenarios where alternative neighbors are available.
available.
However, when there is no alternative neighbor there are several However, when there is no alternative neighbor, there are several
benefits in making NUD try probing for a longer time. One of those benefits to making NUD probe for a longer time. One benefit is to
benefits is to make NUD more robust against transient failures, such make NUD more robust against transient failures, such as spanning
as spanning tree reconvergence and other layer 2 issues that can take tree reconvergence and other layer 2 issues that can take many
many seconds to resolve. Marking the NCE as unreachable in that case seconds to resolve. Marking the NCE as unreachable, in that case,
causes additional multicast on the network. Assuming there are IP causes additional multicast on the network. Assuming there are IP
packets to send, the lack of an NCE will result in multicast Neighbor packets to send, the lack of an NCE will result in multicast Neighbor
Solicitations being sent (to the solicited-node multicast address) Solicitations being sent (to the solicited-node multicast address)
every second instead of the unicast Neighbor Solicitations that NUD every second instead of the unicast Neighbor Solicitations that NUD
sends. sends.
As a result IPv6 Neighbor Discovery is operationally more brittle As a result, IPv6 Neighbor Discovery is operationally more brittle
than IPv4 ARP. For IPv4 there is no mandatory time limit on the than the IPv4 Address Resolution Protocol (ARP). For IPv4, there is
retransmission behavior for ARP [RFC0826] which allows implementors no mandatory time limit on the retransmission behavior for ARP
to pick more robust schemes. [RFC0826], which allows implementors to pick more robust schemes.
The following constant values in [RFC4861] seem to have been made The following constant values in [RFC4861] seem to have been made
part of IPv6 conformance testing: MAX_MULTICAST_SOLICIT, part of IPv6 conformance testing: MAX_MULTICAST_SOLICIT,
MAX_UNICAST_SOLICIT, and RETRANS_TIMER. While such strict MAX_UNICAST_SOLICIT, and RETRANS_TIMER. While such strict
conformance testing seems consistent with [RFC4861], it means that conformance testing seems consistent with [RFC4861], it means that
the standard needs to be updated to allow IPv6 Neighbor Discovery to the standard needs to be updated to allow IPv6 Neighbor Discovery to
be as robust as ARP. be as robust as ARP.
This document updates RFC 4861 to relax the retransmission rules. This document updates RFC 4861 to relax the retransmission rules.
Additional motivations for making IPv6 Neighbor Discovery more robust Additional motivations for making IPv6 Neighbor Discovery more robust
in the face of degenerate conditions are covered in [RFC6583]. in the face of degenerate conditions are covered in [RFC6583].
2. Definition Of Terms 2. Definition of Terms
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Protocol Updates 3. Protocol Updates
Discarding the NCE after after three packets spaced one second apart Discarding the NCE after three packets spaced one second apart is
is only needed when an alternative neighbor is available, such as an only needed when an alternative neighbor is available, such as an
additional default router or a redirect. additional default router or discarding an NCE created by a Redirect.
If an implementation transmits more than MAX_UNICAST_SOLICIT/ If an implementation transmits more than MAX_UNICAST_SOLICIT/
MAX_MULTICAST_SOLICIT packets then it SHOULD use exponential backoff MAX_MULTICAST_SOLICIT packets, then it SHOULD use the exponential
of the retransmit timer. This is to avoid any significant load due backoff of the retransmit timer. This is to avoid any significant
to a steady background level of retransmissions from implementations load due to a steady background level of retransmissions from
that retransmit a large number of NSes before discarding the NCE. implementations that retransmit a large number of Neighbor
Solicitations (NS) before discarding the NCE.
Even if there is no alternative neighbor, the protocol needs to be Even if there is no alternative neighbor, the protocol needs to be
able to handle the case when the link-layer address of the neighbor/ able to handle the case when the link-layer address of the neighbor/
target has changed by switching to multicast Neighbor Solicitations target has changed by switching to multicast Neighbor Solicitations
at some point in time. at some point in time.
In order to capture all the cases above this document introduces a In order to capture all the cases above, this document introduces a
new UNREACHABLE state in the conceptual model described in [RFC4861]. new UNREACHABLE state in the conceptual model described in [RFC4861].
A NCE in the UNREACHABLE state retains the link-layer address, and An NCE in the UNREACHABLE state retains the link-layer address, and
IPv6 packets continue to be sent to that link-layer address. But in IPv6 packets continue to be sent to that link-layer address. But in
the UNREACHABLE state the NUD Neighbor Solicitations are multicast the UNREACHABLE state, the NUD Neighbor Solicitations are multicast
(to the solicited-node multicast address), using a timeout that (to the solicited-node multicast address), using a timeout that
follows an exponential backoff. follows an exponential backoff.
In the places where RFC4861 says to to discard/delete the NCE after N In the places where [RFC4861] says to discard/delete the NCE after N
probes (Section 7.3, 7.3.3 and Appendix C) this document instead probes (Sections 7.3 and 7.3.3, and Appendix C), this document
specifies a transition to the UNREACHABLE state. instead specifies a transition to the UNREACHABLE state.
If the Neighbor Cache Entry was created by a redirect, a node MAY If the Neighbor Cache Entry was created by a Redirect message, a node
delete the NCE instead of changing its state to UNREACHABLE. In any MAY delete the NCE instead of changing its state to UNREACHABLE. In
case, the node SHOULD NOT use an NCE created by a Redirect to send any case, the node SHOULD NOT use an NCE created by a Redirect to
packets if that NCE is in UNREACHABLE state. Packets should be sent send packets if that NCE is in the UNREACHABLE state. Packets should
following the next-hop selection algorithm in [RFC4861], Section 5.2, be sent following the next-hop selection algorithm in [RFC4861],
which disregards NCEs that are not reachable. Section 5.2, which disregards NCEs that are not reachable.
The default router selection in [RFC4861], Section 6.3.6 says to Section 6.3.6 of [RFC4861] indicates that default routers that are
prefer default routers that are "known to be reachable". For the "known to be reachable" are preferred. For the purposes of that
purposes of that section, if the NCE for the router is in UNREACHABLE section, if the NCE for the router is in the UNREACHABLE state, it is
state, it is not known to be reachable. Thus the particular text in not known to be reachable. Thus, the particular text in
section 6.3.6 which says "in any state other than INCOMPLETE" needs Section 6.3.6 that says "in any state other than INCOMPLETE" needs to
to be extended to say "in any state other than INCOMPLETE or be extended to say "in any state other than INCOMPLETE or
UNREACHABLE". UNREACHABLE".
Apart from the use of multicast NS instead of unicast NS, and the Apart from the use of multicast NS instead of unicast NS, and the
exponential backoff of the timer, the UNREACHABLE state works the exponential backoff of the timer, the UNREACHABLE state works the
same as the current PROBE state. same as the current PROBE state.
A node MAY garbage collect a Neighbor Cache Entry at any time as A node MAY garbage collect a Neighbor Cache Entry at any time as
specified in RFC 4861. This freedom to garbage collect does not specified in [RFC4861]. This freedom to garbage collect does not
change with the introduction of the UNREACHABLE state in the change with the introduction of the UNREACHABLE state in the
conceptual model. An implementation MAY prefer garbage collecting conceptual model. An implementation MAY prefer garbage collecting
UNREACHABLE NCEs over other NCEs. UNREACHABLE NCEs over other NCEs.
There is a non-obvious extension to the state machine description in There is a non-obvious extension to the state-machine description in
Appendix C in RFC 4861 in the case for "NA, Solicited=1, Override=0. Appendix C of [RFC4861] in the case for "NA, Solicited=1, Override=0.
Different link-layer address than cached". There we need to add Different link-layer address than cached". There we need to add
"UNREACHABLE" to the current list of "STALE, PROBE, Or DELAY". That "UNREACHABLE" to the current list of "STALE, PROBE, Or DELAY". That
is, the NCE would be unchanged. Note that there is no corresponding is, the NCE would be unchanged. Note that there is no corresponding
change necessary to the text in [RFC4861], Section 7.2.5, since it is change necessary to the text in [RFC4861], Section 7.2.5, since it is
phrased using "Otherwise" instead of explicitly listing the three phrased using "Otherwise" instead of explicitly listing the three
states. states.
The other state transitions described in Appendix C handle the The other state transitions described in Appendix C handle the
introduction of the UNREACHABLE state without any change, since they introduction of the UNREACHABLE state without any change, since they
are described using "not INCOMPLETE". are described using "not INCOMPLETE".
There is also the more obvious change already described above. RFC There is also the more obvious change already described above.
4861 has this: [RFC4861] has this:
State Event Action New state State Event Action New state
PROBE Retransmit timeout, Discard entry - PROBE Retransmit timeout, Discard entry -
N or more N or more
retransmissions. retransmissions.
That needs to be replaced by: That needs to be replaced by:
State Event Action New state State Event Action New state
skipping to change at page 6, line 7 skipping to change at page 5, line 34
UNREACHABLE Retransmit timeout Increase timeout UNREACHABLE UNREACHABLE Retransmit timeout Increase timeout UNREACHABLE
Send multicast NS Send multicast NS
The exponential backoff SHOULD be clamped at some reasonable maximum The exponential backoff SHOULD be clamped at some reasonable maximum
retransmit timeout, such as 60 seconds (see MAX_RETRANS_TIMER below). retransmit timeout, such as 60 seconds (see MAX_RETRANS_TIMER below).
If there is no IPv6 packet sent using the UNREACHABLE NCE, then it is If there is no IPv6 packet sent using the UNREACHABLE NCE, then it is
RECOMMENDED to stop the retransmits of the multicast NS until either RECOMMENDED to stop the retransmits of the multicast NS until either
the NCE is garbage collected or there are IPv6 packets sent using the the NCE is garbage collected or there are IPv6 packets sent using the
NCE. The multicast NS and associated exponential backoff can be NCE. The multicast NS and associated exponential backoff can be
applied on the condition of the continued use of the NCE to send IPv6 applied on the condition of continued use of the NCE to send IPv6
packets to the recorded link-layer address. packets to the recorded link-layer address.
A node can unicast the first few Neighbor Solicitation messages even A node can unicast the first few Neighbor Solicitation messages even
while in UNREACHABLE state, but it MUST switch to multicast Neighbor while in the UNREACHABLE state, but it MUST switch to multicast
Solicitations within 60 seconds of the initial retransmission to be Neighbor Solicitations within 60 seconds of the initial
able to handle a link-layer address change for the target. The retransmission to be able to handle a link-layer address change for
example below shows such behavior. the target. The example below shows such behavior.
4. Example Algorithm 4. Example Algorithm
This section is NOT normative, but specifies a simple implementation This section is NOT normative but specifies a simple implementation
which conforms with this document. The implementation is described that conforms with this document. The implementation is described
using operator configurable values that allows it to be configured in using operator-configurable values that allow it to be configured to
a way to be compatible with the retransmission behavior in [RFC4861]. be compatible with the retransmission behavior in [RFC4861]. The
The operator can configure the values for MAX_UNICAST_SOLICIT, operator can configure the values for MAX_UNICAST_SOLICIT,
MAX_MULTICAST_SOLICIT, RETRANS_TIMER, and the new BACKOFF_MULTIPLE, MAX_MULTICAST_SOLICIT, RETRANS_TIMER, and the new BACKOFF_MULTIPLE,
MAX_RETRANS_TIMER and MARK_UNREACHABLE. This allows the MAX_RETRANS_TIMER, and MARK_UNREACHABLE. This allows the
implementation to be as simple as: implementation to be as simple as:
next_retrans = ($BACKOFF_MULTIPLE ^ $solicit_retrans_num) * next_retrans = ($BACKOFF_MULTIPLE ^ $solicit_retrans_num) *
$RetransTimer * $JitterFactor where solicit_retrans_num is zero for $RetransTimer * $JitterFactor where solicit_retrans_num is zero for
the first transmission, and JitterFactor is a random value between the first transmission, and JitterFactor is a random value between
MIN_RANDOM_FACTOR and MAX_RANDOM_FACTOR [RFC4861] to avoid any MIN_RANDOM_FACTOR and MAX_RANDOM_FACTOR [RFC4861] to avoid any
synchronization of transmissions from different hosts. synchronization of transmissions from different hosts.
After MARK_UNREACHABLE transmissions the implementation would mark After MARK_UNREACHABLE transmissions, the implementation would mark
the NCE UNREACHABLE and as result explore alternate next hops. After the NCE UNREACHABLE and as a result explore alternate next hops.
MAX_UNICAST_SOLICIT the implementation would switch to multicast NUD After MAX_UNICAST_SOLICIT, the implementation would switch to
probes. multicast NUD probes.
The behavior of this example algorithm is to have 5 attempts, with The behavior of this example algorithm is to have 5 attempts, with
timing spacing of 0 (initial request), 1 second later, 3 seconds time spacing of 0 (initial request), 1 second later, 3 seconds after
after the first retransmission, then 9, then 27, and switch to the first retransmission, then 9, then 27, and switch to UNREACHABLE
UNREACHABLE after the first three transmissions. Thus relative to after the first three transmissions. Thus, relative to the time of
the time of the first transmissions the retransmissions would occur the first transmissions, the retransmissions would occur at 1 second,
at 1 second, 4 seconds, 13 seconds, and finally 40 seconds. At 4 4 seconds, 13 seconds, and finally 40 seconds. At 4 seconds from the
seconds from the first transmission the NCE would be marked first transmission, the NCE would be marked UNREACHABLE. That
UNREACHABLE. That behavior corresponds to: behavior corresponds to:
MAX_UNICAST_SOLICIT=5 MAX_UNICAST_SOLICIT=5
RETRANS_TIMER=1 (default) RETRANS_TIMER=1 (default)
MAX_RETRANS_TIMER=60 MAX_RETRANS_TIMER=60
BACKOFF_MULTIPLE=3 BACKOFF_MULTIPLE=3
MARK_UNREACHABLE=3 MARK_UNREACHABLE=3
After 3 retransmissions the implementation would mark the NCE After 3 retransmissions, the implementation would mark the NCE
UNREACHABLE. That results in trying an alternative neighbor, such as UNREACHABLE. That results in trying an alternative neighbor, such as
another default router or ignoring a redirect as specified in another default router, or ignoring an NCE created by a Redirect as
[RFC4861]. With the above values that would occur after 4 seconds specified in [RFC4861]. With the above values, that would occur
after the first transmission compared to the 2 seconds using the after 4 seconds following the first transmission compared to the
fixed scheme in [RFC4861]. That additional delay is small compared 2 seconds using the fixed scheme in [RFC4861]. That additional
to the default 30,000 milliseconds ReachableTime. delay is small compared to the default ReachableTime of
30,000 milliseconds.
After 5 transmissions, i.e., 40 seconds after the initial After 5 transmissions, i.e., 40 seconds after the initial
transmission, the example behavior is to switch to multicast NUD transmission, the example behavior is to switch to multicast NUD
probes. In the language of the state machine in [RFC4861] that probes. In the language of the state machine in [RFC4861], that
corresponds to the action "Discard entry". Thus any attempts to send corresponds to the action "Discard entry". Thus, any attempts to
future packets would result in sending multicast NS packets. An send future packets would result in sending multicast NS packets. An
implementation MAY retain the backoff value as it switches to implementation MAY retain the backoff value as it switches to
multicast NUD probes. The potential downside of deferring switching multicast NUD probes. The potential downside of deferring switching
to multicast is that it would take longer for NUD to handle a change to multicast is that it would take longer for NUD to handle a change
in a link-layer address i.e., the case when a host or a router in a link-layer address, i.e., the case when a host or a router
changes their link-layer address while keeping the same IPv6 address. changes its link-layer address while keeping the same IPv6 address.
However, [RFC4861] says that a node MAY send unsolicited NS to handle However, [RFC4861] says that a node MAY send unsolicited NS to handle
that case, which is rather infrequent in operational networks. In that case, which is rather infrequent in operational networks. In
any case, the implementation needs to follow the "SHOULD" in section any case, the implementation needs to follow the "SHOULD" in
Section 3 to switch to multicast solutions within 60 seconds after Section 3 to switch to multicast solutions within 60 seconds after
the initial transmission. the initial transmission.
If BACKOFF_MULTIPLE=1, MARK_UNREACHABLE=3 and MAX_UNICAST_SOLICIT=3, If BACKOFF_MULTIPLE=1, MARK_UNREACHABLE=3, and MAX_UNICAST_SOLICIT=3,
you would get the same behavior as in [RFC4861]. you would get the same behavior as in [RFC4861].
An implementation following this algorithm would, if the request was If the request was not answered at first -- due, for example, to a
not answered at first due for example to a transitory condition, transitory condition -- an implementation following this algorithm
retry immediately, and then back off for progressively longer would retry immediately and then back off for progressively longer
periods. This would allow for a reasonably fast resolution time when periods. This would allow for a reasonably fast resolution time when
the transitory condition clears. the transitory condition clears.
Note that RetransTimer and ReachableTime are by default set from the Note that RetransTimer and ReachableTime are by default set from the
protocol constants RETRANS_TIMER and REACHABLE_TIME, but are protocol constants RETRANS_TIMER and REACHABLE_TIME but are
overridden by values advertised in Router Advertisements as specified overridden by values advertised in Router Advertisements as specified
in [RFC4861]. That remains the case even with the protocol updates in [RFC4861]. That remains the case even with the protocol updates
specified in this document. The key values that the operator would specified in this document. The key values that the operator would
configure are BACKOFF_MULTIPLE, MAX_RETRANS_TIMER, configure are BACKOFF_MULTIPLE, MAX_RETRANS_TIMER,
MAX_UNICAST_SOLICIT and MAX_MULTICAST_SOLICIT. MAX_UNICAST_SOLICIT, and MAX_MULTICAST_SOLICIT.
It is be useful to have a maximum value for It is useful to have a maximum value for
($BACKOFF_MULTIPLE^$solicit_attempt_num)*$RetransTimer so that the ($BACKOFF_MULTIPLE^$solicit_attempt_num)*$RetransTimer so that the
retransmissions are not too far apart. The above value of 60 seconds retransmissions are not too far apart. The above value of 60 seconds
for this MAX_RETRANS_TIMER is consistent with DHCPv6. for this MAX_RETRANS_TIMER is consistent with DHCPv6.
5. Acknowledgements 5. Acknowledgements
The comments from Thomas Narten, Philip Homburg, Joel Jaeggli, Hemant The comments from Thomas Narten, Philip Homburg, Joel Jaeggli, Hemant
Singh, Tina Tsou, Suresh Krishnan, and Murray Kucherawy have helped Singh, Tina Tsou, Suresh Krishnan, and Murray Kucherawy have helped
improve this draft. improve this document.
6. Security Considerations 6. Security Considerations
Relaxing the retransmission behavior for NUD is believed to have no Relaxing the retransmission behavior for NUD is believed to have no
impact on security. In particular, it doesn't impact the application impact on security. In particular, it doesn't impact the application
Secure Neighbor Discovery [RFC3971]. of Secure Neighbor Discovery [RFC3971].
7. IANA Considerations
This are no IANA considerations for this document.
8. References 7. References
8.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
Neighbor Discovery (SEND)", RFC 3971, March 2005. Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
8.2. Informative References 7.2. Informative References
[RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
converting network protocol addresses to 48.bit Ethernet converting network protocol addresses to 48.bit Ethernet
address for transmission on Ethernet hardware", STD 37, address for transmission on Ethernet hardware", STD 37,
RFC 826, November 1982. RFC 826, November 1982.
[RFC6583] Gashinsky, I., Jaeggli, J., and W. Kumari, "Operational [RFC6583] Gashinsky, I., Jaeggli, J., and W. Kumari, "Operational
Neighbor Discovery Problems", RFC 6583, March 2012. Neighbor Discovery Problems", RFC 6583, March 2012.
Authors' Addresses Authors' Addresses
Erik Nordmark Erik Nordmark
Arista Networks Arista Networks
Santa Clara, CA Santa Clara, CA
USA USA
Email: nordmark@acm.org EMail: nordmark@acm.org
Igor Gashinsky Igor Gashinsky
Yahoo! Yahoo!
45 W 18th St 45 W 18th St
New York, NY New York, NY
USA USA
Email: igor@yahoo-inc.com EMail: igor@yahoo-inc.com
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