Internet DRAFT - draft-bonica-6man-deprecate-router-alert
draft-bonica-6man-deprecate-router-alert
6man R. Bonica
Internet-Draft Juniper Networks
Updates: RFC 2711 (if approved) 19 February 2024
Intended status: Standards Track
Expires: 22 August 2024
Deprecation Of The IPv6 Router Alert Option
draft-bonica-6man-deprecate-router-alert-02
Abstract
This document deprecates the IPv6 Router Alert Option. Protocols
that use the Router Alert Option may continue to do so, even in
future versions. However, protocols standardized in the future must
not use the Router Alert Option.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 22 August 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Updates To RFC 2711 . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Figure 1 models an Internet router. The router has a forwarding
plane and a control plane.
---------------------------------------------------
| |
| CONTROL PLANE |
| (OSPF, ISIS, BGP) |
| |
| (FIB Read-Write) |
---------------------------------------------------
| / \
| FIB updates and | Messages addressed
| routing protocol | to the router and
| messages to | messages that contain
| other nodes | the Router Alert Option
\ / |
---------------------------------------------------
| |
| FORWARDING PLANE |
| (IPv6) |
| |
| (FIB Read-Only) |
---------------------------------------------------
Figure 1: An Internet Router
IPv6 [RFC8200] operates on the forwarding plane. It:
* Accepts a packet.
* Determines the packet's next hop.
* Forwards the packet to its next hop.
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IPv6 determines a packet's next hop by searching the Forwarding
Information Base (FIB) for an entry that best matches the packet's
destination address. Therefore, IPv6 requires read-only access to
the FIB.
Routing protocols (e.g., OSPF, IS-IS, BGP) operate on a router's
control plane. They create and maintain the FIB by exchanging
routing protocol messages with other nodes. Therefore, the control
plane requires read-write access to the FIB.
The forwarding and control planes communicate with one another as
follows:
* The control plane sends FIB updates to the forwarding plane so it
can maintain a read-only FIB copy.
* The control plane sends routing protocol messages through the
forwarding plane to other nodes.
* The forwarding plane sends routing protocol messages received from
other nodes and addressed to the router to the control plane.
* The forwarding plane sends messages that are not addressed to the
router but include the IPv6 Router Alert Option [RFC2711] to the
control plane. The control plane inspects these messages and
returns them to the forwarding plane so that they can continue on
to their ultimate destination.
Many routers maintain separation between forwarding and control plane
hardware. The forwarding plain is implemented on high-performance
Application Specific Integrated Circuits (ASIC) and Network
Processors (NP), while the control plane is implemented on general-
purpose processors. Therefore, the forwarding plane can process many
more packets per second than the control plane. Given this
difference in packet-handling capabilities, a router's control plane
is more susceptible to a Denial-of-Service (DoS) attack than the
router's forwarding plane.
[RFC6192] demonstrates how a network operator can deploy Access
Control Lists (ACL) that protect the control plane from DoS attack.
These ACLs are effective and efficient when they select packets based
upon information that can be found in a fixed position in the packet
header. However, they become less effective and less efficient when
they must parse an IPv6 Hop-by-hop Options extension header,
searching for the Router Alert Option. Therefore, many network
operators drop or severely rate limit packets that contain the IPv6
Hop-by-hop Options extension header.
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[RFC6398] identifies security considerations associated with the
Router Alert Option. It provides the following recommendations:
* "Network operators SHOULD actively protect themselves against
externally generated IP Router Alert packets."
* "Applications and protocols SHOULD NOT be deployed with a
dependency on processing of the Router Alert Option (as currently
specified) across independent administrative domains in the
Internet."
* "Router implementations of the IP Router Alert Option SHOULD offer
the configuration option to simply ignore the presence of "IP
Router Alert" in IPv4 and IPv6 packets."
* "A router implementation SHOULD forward within the "fast path"
(subject to all normal policies and forwarding rules) a packet
carrying the IP Router Alert Option containing a next level
protocol that is not a protocol of interest to that router."
NOTE: In RFC 6398, the terms "fast path" and "forwarding plane
components" are used synonymously.
Network operators can address all of the security considerations
raised in RFC 6398 by configuring their routers to ignore the Router
Alert Option. However, such configuration may not be possible if
protocol designers continue to design protocols that use the Router
Alert Option. Alternatively, network operators will be required to
deploy the operationally complex and computationally expensive ACLs
described in RFC 6192. Therefore, this document deprecates the IPv6
Router Alert Option.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Updates To RFC 2711
This document deprecates the IPv6 Router Alert Option. Protocols
that use the Router Alert Option MAY continue to do so, even in
future versions. However, protocols standardized in the future MUST
NOT use the Router Alert Option.
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Table 1 contains a list of protocols that use the IPv6 Router Alert
Option. There are no known IPv6 implementations of MPLS PING.
Neither INTSERV nor NSIS are widely deployed. All NSIS protocols are
EXPERIMENTAL. Pragmatic Generic Multicast (PGM) is EXPERIMENTAL and
there are no known IPv6 implementations.
+===================+====================+==========================+
| Protocol | References | Application |
+===================+====================+==========================+
| Multicast | [RFC3810] | IPv6 Multicast |
| Listener | | |
| Discovery Version | | |
| 2 (MLDv2) | | |
+-------------------+--------------------+--------------------------+
+-------------------+--------------------+--------------------------+
| Multicast Router | [RFC4286] | IPv6 Multicast |
| Discovery (MRD) | | |
+-------------------+--------------------+--------------------------+
+-------------------+--------------------+--------------------------+
| Pragmatic General | [RFC3208] | IPv6 Multicast |
| Multicast (PGM) | | |
+-------------------+--------------------+--------------------------+
+-------------------+--------------------+--------------------------+
| MPLS PING | [RFC7506][RFC8029] | MPLS OAM |
+-------------------+--------------------+--------------------------+
+-------------------+--------------------+--------------------------+
| Resource | [RFC3175] | Integrated Services |
| Reservation | [RFC5946] | (INTSERV) [RFC1633] |
| Protocol (RSVP) | [RFC6016] | (Not Traffic |
| | [RFC6401] | engineering or MPLS |
| | | signaling) |
+-------------------+--------------------+--------------------------+
+-------------------+--------------------+--------------------------+
| Next Steps In | [RFC5979] | NSIS [RFC4080] |
| Signaling (NSIS) | [RFC5971] | |
+-------------------+--------------------+--------------------------+
Table 1: Protocols That Use The IPv6 Router Alert Option
4. Security Considerations
This document extends the security considerations provided in RFC
2711, RFC 6192 and RFC 6398.
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5. IANA Considerations
IANA is requested to mark the Router Alert Option as Deprecated in
the Destination Options and Hop-by-hop Options Registry (
https://www.iana.org/assignments/ipv6-parameters/
ipv6-parameters.xhtml#ipv6-parameters-2) and add a pointer to this
document.
6. Acknowledgements
Thanks to Brian Carpenter, Toerless Eckert, Adrian Farrel, and Bob
Hinden for their reviews of this document.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
RFC 2711, DOI 10.17487/RFC2711, October 1999,
<https://www.rfc-editor.org/info/rfc2711>.
[RFC6398] Le Faucheur, F., Ed., "IP Router Alert Considerations and
Usage", BCP 168, RFC 6398, DOI 10.17487/RFC6398, October
2011, <https://www.rfc-editor.org/info/rfc6398>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
7.2. Informative References
[RFC1633] Braden, R., Clark, D., and S. Shenker, "Integrated
Services in the Internet Architecture: an Overview",
RFC 1633, DOI 10.17487/RFC1633, June 1994,
<https://www.rfc-editor.org/info/rfc1633>.
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[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations",
RFC 3175, DOI 10.17487/RFC3175, September 2001,
<https://www.rfc-editor.org/info/rfc3175>.
[RFC3208] Speakman, T., Crowcroft, J., Gemmell, J., Farinacci, D.,
Lin, S., Leshchiner, D., Luby, M., Montgomery, T., Rizzo,
L., Tweedly, A., Bhaskar, N., Edmonstone, R.,
Sumanasekera, R., and L. Vicisano, "PGM Reliable Transport
Protocol Specification", RFC 3208, DOI 10.17487/RFC3208,
December 2001, <https://www.rfc-editor.org/info/rfc3208>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>.
[RFC4080] Hancock, R., Karagiannis, G., Loughney, J., and S. Van den
Bosch, "Next Steps in Signaling (NSIS): Framework",
RFC 4080, DOI 10.17487/RFC4080, June 2005,
<https://www.rfc-editor.org/info/rfc4080>.
[RFC4286] Haberman, B. and J. Martin, "Multicast Router Discovery",
RFC 4286, DOI 10.17487/RFC4286, December 2005,
<https://www.rfc-editor.org/info/rfc4286>.
[RFC5946] Le Faucheur, F., Manner, J., Narayanan, A., Guillou, A.,
and H. Malik, "Resource Reservation Protocol (RSVP)
Extensions for Path-Triggered RSVP Receiver Proxy",
RFC 5946, DOI 10.17487/RFC5946, October 2010,
<https://www.rfc-editor.org/info/rfc5946>.
[RFC5971] Schulzrinne, H. and R. Hancock, "GIST: General Internet
Signalling Transport", RFC 5971, DOI 10.17487/RFC5971,
October 2010, <https://www.rfc-editor.org/info/rfc5971>.
[RFC5979] Shen, C., Schulzrinne, H., Lee, S., and J. Bang, "NSIS
Operation over IP Tunnels", RFC 5979,
DOI 10.17487/RFC5979, March 2011,
<https://www.rfc-editor.org/info/rfc5979>.
[RFC6016] Davie, B., Le Faucheur, F., and A. Narayanan, "Support for
the Resource Reservation Protocol (RSVP) in Layer 3 VPNs",
RFC 6016, DOI 10.17487/RFC6016, October 2010,
<https://www.rfc-editor.org/info/rfc6016>.
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[RFC6192] Dugal, D., Pignataro, C., and R. Dunn, "Protecting the
Router Control Plane", RFC 6192, DOI 10.17487/RFC6192,
March 2011, <https://www.rfc-editor.org/info/rfc6192>.
[RFC6401] Le Faucheur, F., Polk, J., and K. Carlberg, "RSVP
Extensions for Admission Priority", RFC 6401,
DOI 10.17487/RFC6401, October 2011,
<https://www.rfc-editor.org/info/rfc6401>.
[RFC7506] Raza, K., Akiya, N., and C. Pignataro, "IPv6 Router Alert
Option for MPLS Operations, Administration, and
Maintenance (OAM)", RFC 7506, DOI 10.17487/RFC7506, April
2015, <https://www.rfc-editor.org/info/rfc7506>.
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>.
Author's Address
Ron Bonica
Juniper Networks
2251 Corporate Park Drive
Herndon, Virginia 20171
United States of America
Email: rbonica@juniper.net
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