Network Working Group F. Le Faucheur, Ed.
Internet-Draft Cisco
Intended status: BCP October 26, 2009
Expires: April 29, 2010
IP Router Alert Considerations and Usage
draft-rahman-rtg-router-alert-considerations-03
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Abstract
The IP Router Alert Option is an IP option that alerts transit
routers to more closely examine the contents of an IP packet. RSVP,
PGM, IGMP/MLD, MRD and GIST are some of the protocols that make use
of the IP Router Alert option. This document discusses security
aspects and usage guidelines around the use of the current IP Router
Alert option. Specifically, it provides recommendation against using
the Router Alert in the end-to-end open Internet as well as identify
controlled environments where protocols depending on Router Alert can
be used safely. It also provides recommendation about protection
approaches for Service Providers. Finally it provides brief
guidelines for Router Alert implementation on routers.
Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Conventions Used in This Document . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Security Concerns of Router Alert . . . . . . . . . . . . . . 7
4. Guidelines for use of Router Alert . . . . . . . . . . . . . . 10
4.1. Use of Router Alert End-to-End In the Internet (Router
Alert in Peer Model) . . . . . . . . . . . . . . . . . . . 10
4.2. Use of Router Alert In Controlled Environments . . . . . . 11
4.2.1. Use of Router Alert Within an Administrative Domain . 11
4.2.2. Use of Router Alert In Overlay Model . . . . . . . . . 13
4.3. Router Alert Protection Approaches for Service
Providers . . . . . . . . . . . . . . . . . . . . . . . . 16
5. Guidelines for Router Alert Implementation . . . . . . . . . . 18
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
10.1. Normative References . . . . . . . . . . . . . . . . . . . 23
10.2. Informative References . . . . . . . . . . . . . . . . . . 23
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 25
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1. Terminology
For readability, this document uses the following loosely defined
terms:
o Slow path : Software processing path for packets
o Fast path : ASIC/Hardware processing path for packets
1.1. Conventions Used in This Document
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 [RFC2119].
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2. Introduction
[RFC2113] and [RFC2711] respectively define the IPv4 and IPv6 Router
Alert Option (RAO). In this document, we collectively refer to those
as the IP Router Alert. The IP Router Alert Option is an IP option
that alerts transit routers to more closely examine the contents of
an IP packet.
RSVP ([RFC2205], [RFC3175], [RFC3209]), PGM ([RFC3208]), IGMP
([RFC3376]), MLD ([RFC2710], [RFC3810]), MRD ([RFC4286]) and NSIS
General Internet Signalling Transport (GIST) ([I-D.ietf-nsis-ntlp])
are some of the protocols that make use of the IP Router Alert.
Section 3 describes the security concerns associated with the use of
the Router Alert option.
Section 4 provides guidelines for the use of Router Alert. More
specifically, Section 4.1 recommends that Router Alert not be used
for end to end applications over the Internet, while Section 4.2
presents controlled environments where applications/protocols relying
on IP Router Alert can be deployed effectively and safely.
Section 4.3 provides recommendations on protection approaches to be
used by Service Providers in order to protect their network from
Router Alert based attacks.
Finally, Section 5 provides generic recommendations for router
implementation of Router Alert aiming at increasing protection
against attacks.
The present document discusses considerations and practises based on
the current specification of IP Router Alert ([RFC2113], [RFC2711]).
Possible future enhancements to the specification of IP Router Alert
(in view of reducing the security risks associated with the use of IP
Router Alert) are outside the scope of this document. A proposal for
such enhancements can be found in
[I-D.narayanan-rtg-router-alert-extension].
The IPv6 base specification [RFC2460] defines the hop-by-hop option
extension header. The hop-by-hop option header is used to carry
optional information that must be examined by every node along a
packet's delivery path. The IPv6 Router Alert Option is one
particular hop by hop option. Similar security concerns to those
discussed in the present document for the IPv6 Router Alert apply
more generically to the concept of IPv6 hop-by-hop option extension
header. However, addressing the broader concept of IPv6 hop-by-hop
option thoroughly would require additional material so as to cover
additional considerations associated with it (such as the attacks
effectiveness depending on how many options are included and on the
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range from to which the option-type value belongs, etc.), so this is
kept outside the scope of the present document. A detailed
discussion about security risks and proposed remedies associated with
IPv6 hop-by-hop option can be found in [I-D.krishnan-ipv6-hopbyhop].
The IPv4 base specification [RFC0791] defines a general notion of
IPv4 options that can be included in the IPv4 header (without
distinguishing between hop-by-hop versus end-to-end option). The
IPv4 Router Alert Option is one particular IPv4 option. Similar
security concerns to those discussed in the present document for the
IPv4 Router Alert apply more generically to the concept of IPv4
option. However, addressing the broader concept of IPv4 option
thoroughly would require additional material so as to cover
additional considerations associated with it (such as lack of option
ordering, etc.), so this is kept outside the scope of the present
document.
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3. Security Concerns of Router Alert
The IP Router Alert option is defined ([RFC2113], [RFC2711]) as a
mechanism that alerts transit routers to more closely examine the
contents of an IP packet. [RFC4081] and [RFC2711] mention the
security risks associated with the use of the IP Router Alert:
flooding a router with bogus (or simply undesired) IP datagrams which
contain the IP Router Alert could impact operation of the router in
undesirable ways. For example, assuming the router punts the
datagrams containing the IP Router Alert option to the slow path,
such an attack could consume a significant share of the router's slow
path and could also lead to packet drops in the slow path (thus,
affecting operation of all other applications and protocols operating
in the slow path).
Furthermore, [RFC2113] specifies no (and [RFC2711] specifies very
limited) mechanism for identifying different users of IP Router
Alert. As a result, many fast switching implementations of IP Router
Alert punt most/all packets marked with IP Router Alert into the slow
path (unless configured to systematically ignore or drop all Router
Alert packets).
Some IP Router Alert implementations may be able to take into account
the IP PID [RFC0791] as a discriminator for the punting decision for
different protocols using IP Router Alert. However, this still only
allows very coarse triage among various protocols using IP Router
Alert for two reasons. First, the IP PID is the same when IP Router
Alert is used for different applications of the same protocol (e.g.,
RSVP vs. RSVP-TE), or when IP Router Alert is used for different
contexts of the same application (e.g., different levels of RSVP
aggregation [RFC3175]). Thus, it is not possible to achieve the
necessary triage in the fast path across IP Router Alert packets from
different applications or from different contexts of an application.
Secondly, some protocols requiring punting may be carried over a
transport protocol (e.g., TCP or UDP) possibly because they require
the services of that transport protocol or perhaps because the
protocol does not justify allocation of a scarce IP PID value. Thus,
considering the PID does not allow triage in the fast path of IP
Router Alert packets from different protocols sharing the same
transport protocol. Therefore, It is generally not possible to
ensure that only the IP Router Alert packets of interest are punted
to the slow path while other IP Router Alert packets are efficiently
forwarded (i.e., in fast path).
Some IP Router Alert implementations may be able to take into account
the value field inside the router alert option. However, only one
value (zero) was defined in [RFC2113] and no IANA registry for IPv4
Router Alert values was available until recently. So this did not
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allow most IPv4 Router Alert implementation to support useful
classification based on the value field in the fast path. Also,
while [RFC2113] states that unknown values should be ignored (i.e.
The packets should be forwarded as normal IP traffic), it has been
reported that some existing implementations simply ignore the value
field completely (i.e. Process any packet with an IPv4 Router Alert
regardless of its option value). An IANA registry for further
allocation of IPv4 Router Alert values has been introduced recently
([RFC5350]) but this would only allow coarse-grain classification,
when, and if, supported by implementations. For IPv6, [RFC2711]
states that "the value field can be used by an implementation to
speed processing of the datagram within the transit router" and
defines an IANA registry for these values. But again, this only
allows coarse-grain classification. Besides, some existing IPv6
Router Alert implementations are reported to depart from that
behavior.
[RFC2711] mentions that limiting, by rate or some other means, the
use of IP Router Alert option is a way of protecting against a
potential attack. However, if rate limiting is used as a protection
mechanism but if the granularity of the rate limiting is not fine
enough to distinguish among IP Router Alert packet of interest from
unwanted IP Router Alert packet, a IP Router Alert attack could still
severely degrade operation of protocols of interest that depend on
the use of IP Router Alert.
In a nutshell, the IP router alert option does not provide a
convenient universal mechanism to accurately and reliably distinguish
between IP Router Alert packets of interest and unwanted IP Router
Alert packets. This, in turn, creates a security concern when IP
Router Alert option is used, because, short of appropriate router
implementation specific mechanisms, the router slow path is at risk
of being flooded by unwanted traffic.
It can be observed that opening up a hole in the control plane of
Service Provider routers is commonly done for other applications such
as BGP peering. However, the resulting DOS attack vector is arguably
more serious with Router Alert option than with BGP peering for a
number of reasons including:
o with BGP Peering, the control plane hole is only open on the edge
routers and core routers are completely isolated from any direct
control plane exchange with entities outside the administrative
domain; with BGP, a DOS attack would only affect the edge
router(s), while with Router Alert option, the attack could
propagate to core routers;
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o with BGP, the BGP policy control would typically prevent re-
injection of undesirable information out of the attacked device,
while with Router-Alert option, the non-filtered attacking
messages would typically be forwarded downstream.
o With BGP, edge routers only exchange control plane information
with pre-identified peers and can easily filter out any control
plane traffic coming from other peers, while the Router-Alert
option can be received in a datagram with any destination address
and any destination source.
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4. Guidelines for use of Router Alert
4.1. Use of Router Alert End-to-End In the Internet (Router Alert in
Peer Model)
Because of the security concerns associated with Router Alert
discussed in Section 3, network operators need to actively protect
themselves against externally generated IP Router Alert packets.
Because there is no convenient universal mechanisms to triage between
desired and undesired router alert packets, network operators
currently often protect themselves in ways that isolate them from
externally generated IP Router Alert packets. This may (ideally) be
achieved by tunneling IP Router Alert packets
[I-D.dasmith-mpls-ip-options] so that the IP Router Alert option is
hidden through that network, or it may be achieved via mechanisms
resulting in occasional (e.g., rate limiting) or systematic drop of
IP Router Alert packets.
Thus, it is RECOMMENDED that applications and protocols not be
deployed with a dependency on processing of the Router Alert option
(as currently specified) across independent administrative domains in
the Internet. Figure 1 illustrates such a hypothetical use of Router
Alert end-to-end in the Internet. We refer to such a model of Router
Alert option use as a "Peer Model" Router Alert option use, since
core routers in different administrative domains would partake in
processing of Router Alert option datagrams associated with the same
signalling flow.
-------- -------- -------- --------
/ A \ / B \ / C \ / D \
| (*) | | (*) | | (*) | | (*) |
| | |<============>| |<=============>| |<=============>| | |
| - | | - | | - | | - |
\ / \ / \ / \ /
-------- -------- -------- --------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
Figure 1: Use of Router Alert End-to-End in the Open Internet (Router
Alert in Peer Model)
While this recommendation is framed here specifically in the context
of router alert, the fundamental security risk that network operators
want to preclude is to allow devices/protocols that are outside of
their administrative domain (and therefore not controlled) to tap
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into the control plane of their core routers. Whether this control
plane access is provided through router alert option or would be
provided by any other mechanism (e.g. Deep packet inspection)
probably results in similar security concerns. In other words, the
fundamental security concern is associated with the notion of end to
end signaling in a Peer Model across domains in the Internet. As a
result, it is expected that network operators would typically not
want to have their core routers partake in end-to-end signalling with
external uncontrolled devices through the open Internet, and
therefore prevent deployment of end to end signalling in a Peer model
through their network (regardless of whether that signalling uses
Router Alert or not).
4.2. Use of Router Alert In Controlled Environments
4.2.1. Use of Router Alert Within an Administrative Domain
In some controlled environments such as within a given Administrative
Domain, the network administrator can determine that IP Router Alert
packets will only be received from trusted well-behaved devices or
can establish that specific protection mechanisms (e.g., RAO
filtering and rate-limiting) against the plausible RAO-based DoS
attacks are sufficient. In that case, an application relying on
exchange and handling of RAO packets (e.g., RSVP) MAY be safely
deployed within the controlled network. A private enterprise network
firewalled from the Internet and using RSVP reservations for voice
and video flows may be an example of such controlled environment.
Such an environment is illustrated in Figure 2.
------------------------- -------- --------
/ A \ / B \ / C \
| (*) (*) | -- | | | |
| | |<============>| | |--|FW|--| |--------| |
| - - | -- | | | |
\ / \ / \ /
------------------------- -------- --------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
FW Firewall
Figure 2: Use of Router Alert Within an Administrative Domain
In some controlled environments, several Administrative Domains have
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a special relationship whereby they cooperate very tightly and
effectively operate as a single trust domain. In that case, one
domain is willing to trust another with respect to the traffic
injected across the boundary. In other words, a downstream domain is
willing to trust that the traffic injected at the boundary has been
properly validated/filtered by the upstream domain. Where it has
been established that such trust can be applied to router alert
option packets, an application relying on exchange and handling of
RAO packets (e.g., RSVP) MAY be safely deployed within such a
controlled environment. The entity within a company responsible for
operating multimedia endpoints and the entity within the same company
responsible for operating the network may be an example of such
controlled environment. For example, they may collaborate so that
RSVP reservations can be used for video flows from endpoints to
endpoints through the network.
In some environments, the network administrator can reliably ensure
that router alert packets from any untrusted device (e.g., from
external routers) are prevented from entering a trusted area (e.g.,
the internal routers). For example, this may be achieved by ensuring
that routers straddling the trust boundary (e.g., edge routers)
always encapsulate those packets (without setting IP Router Alert -or
equivalent- in the encapsulating header) through the trusted area (as
discussed in [I-D.dasmith-mpls-ip-options]). In such environments,
the risks of DOS attacks through the IP Router Alert vector is
removed in the trusted area (or greatly reduced) even if IP Router
Alert is used inside the trusted area (say for RSVP-TE). Thus an
application relying on IP Router Alert MAY be safely deployed within
the trusted area. A Service Provider running RSVP-TE within his
network may be an example of such protected environment. Such an
environment is illustrated in Figure 3.
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-------- -------------------------- --------
/ A \ / B \ / C \
| | | (*) (*) | | |
| |-------TT | |<=============>| | TT------- | |
| | | - - | | |
\ / \ / \ /
-------- -------------------------- --------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
TT Tunneling of Router Alert option datagrams
Figure 3: Use of Router Alert Within an Administrative Domain
4.2.2. Use of Router Alert In Overlay Model
In some controlled environment:
o the sites of a network A are interconnected through a service
provider network B
o the service provider network B protects itself from IP Router
Alert messages without dropping those when they transit over the
transit network (for example using mechanisms discussed in
[I-D.dasmith-mpls-ip-options])
In such controlled environment, an application relying on exchange
and handling of RAO packets (e.g., RSVP) in the network A sites (but
not inside network B) MAY be safely deployed. We refer to such a
deployment as a use of Router Alert in a Water-Tight Overlay.
"Overlay" because Router Alert option datagrams are used in network A
on top of, and completely transparently to, network B. "Water-Tight"
because router alert option datagrams from A cannot leak inside
network B. A private enterprise intranet, whose sites are
interconnected through a Service Prover network, and using RSVP to
perform reservations within the enterprise sites for voice and video
flows may be an example of such controlled environment. Such an
environment is illustrated in Figure 4.
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-------- --------
/ A \ / A \
| (*) | | (*) |
| | |<=================================>| | | |
| - | | - |
\ / \ /
-------- --------
\ /
\ ------------------------- /
\ / B \ /
\| |/
TT TT
| |
\ /
-------------------------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
TT Tunneling of Router Alert option datagrams
Figure 4: Use of Router Alert In Water-tight Overlay
In the controlled environment described above, an application relying
on exchange and handling of RAO packets (e.g. RSVP-TE) in the
service provider network B (but not in network A) MAY also be safely
deployed simultaneously. Such an environment with independent,
isolated, deployment of router alert in overlay at two levels is
illustrated in Figure 5.
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-------- --------
/ A \ / A \
| (*) | | (*) |
| | |<=================================>| | | |
| - | | - |
\ / \ /
-------- --------
\ /
\ ------------------------- /
\ / B \ /
\| (*) (*) |/
TT | |<============>| | TT
| - - |
\ /
-------------------------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
TT Tunneling of Router Alert option datagrams
Figure 5: Use of Router Alert In Water-tight Overlay at Two Levels
In some controlled environment:
o the sites of a network A are interconnected through a service
provider network B
o the service provider B processes router alert packets on the edge
routers and protect these edge routers against RAO based attacks
using mechanisms such as (possibly per port) RAO rate limiting and
filtering
o the service provider network B protects its core routers from
Router Alert messages without dropping those when they transit
over the transit network (for example using mechanisms discussed
in [I-D.dasmith-mpls-ip-options])
In such controlled environment, an application relying on exchange
and handling of RAO packets (e.g., RSVP) in the network A sites and
in network B Edges (but not in the core of network B) MAY be safely
deployed. We refer to such a deployment as a use of Router Alert in
a Leak-Controlled Overlay. "Overlay" because Router Alert option
datagrams are used in network A on top of, and completely
transparently to, network B core. "Leak-Controlled" because router
alert option datagrams from A leak inside network B's B edges but not
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inside network B's core. A private enterprise intranet, whose sites
are interconnected through a Service Prover network, using RSVP for
voice and video within network A sites as well as on Network B's edge
to extend the reservation onto the attachment links between A and B
(as specified in [I-D.ietf-tsvwg-rsvp-l3vpn]) may be an example of
such controlled environment. Such an environment is illustrated in
Figure 4.
-------- --------
/ A \ / A \
| | | |
| | ------------------------ | |
| (*) | /(*) (*) \ | (*) |
| | |<======>| |<============>| |<=====>| | | |
| - | | - - | | - |
\ / | \ - - / | \ /
-------- | TT-| | | |-TT | --------
| - - |
\ /
------------------------
(*) closer examination of Router Alert option datagrams
<==> flow of Router Alert option datagrams
TT Tunneling of Router Alert option datagrams
Figure 6: Use of Router Alert In Leak-Controlled Overlay
4.3. Router Alert Protection Approaches for Service Providers
Section 3 discusses the security risks associated with the use of the
IP Router Alert and how it opens up a DOS vector in the router
control plane. Thus, it is RECOMMENDED that a Service Provider
implements strong protection of his network against attacks based on
IP Router Alert.
As discussed in Section 4.2.2 some applications can benefit from the
use of IP Router Alert packets in an Overlay model (i.e. Where
Router Alert packets are exchanged transparently on top of a Service
Provider). Thus, it is RECOMMENDED that a Service Provider protects
his network from attacks based on IP Router Alert using mechanisms
that avoid (or at least minimize) dropping of end to end IP Router
Alert packets (other than those involved in an attack).
For example, if the Service Provider does not run any protocol
depending on IP Router Alert within his network, he may elect to
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simply turn-off punting/processing of IP Router Alert packet on his
routers; this will ensure that end-to-end IP Router Alert packet
transit transparently and safely through his network.
As another example, using protection mechanisms such selective
filtering and rate-limiting (that Section 5 suggests be supported by
IP Router Alert implementations) a Service Provider can protect the
operation of a protocol depending on IP Router Alert within his
network (e.g., RSVP-TE) while at the same time transporting IP Router
Alert packets carrying another protocol that may be used end to end.
Note that the Service Provider might additionally use protocol
specific mechanisms that reduce the dependency on Router Alert for
operation of this protocol inside the Service Provider environment;
use of RSVP refresh reduction mechanisms ([RFC2961]) would be an
example of such mechanisms in the case where the Service Provider is
running RSVP-TE within his network since this allows refresh of
existing Path and Resv states without use of the IP Router Alert
option.
As yet another example, using mechanisms such as those discussed in
[I-D.dasmith-mpls-ip-options] a Service Provider can safely protect
the operation of a protocol depending on IP Router Alert within his
network (e.g., RSVP-TE) while at the same time safely transporting IP
Router Alert packets carrying another protocol that may be used end
to end (e.g., IPv4/IPv6 RSVP).
As a last resort, if the SP does not have any means to safely
transport end to end IP Router Alert option packets over his network,
the SP MAY drop those packets. It must be noted that this has the
undesirable consequence of preventing the use of the Router Alert
option in the Overlay Model on top of this network, and therefore
prevents users of that network from deploying a number of valid
applications/protocols in their environment.
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5. Guidelines for Router Alert Implementation
It is RECOMMENDED that router implementations of IP Router Alert
option include protection mechanisms against Router Alert based DOS
attacks appropriate for their targeted deployment environments. For
example, this can include ability on an edge router to "tunnel" IP
Router Alert option of received packets when forwarding those over
the core as discussed in [I-D.dasmith-mpls-ip-options]. As another
example, although not always available from current implementations,
new implementations may include protection mechanisms such as
selective (possibly dynamic) filtering and rate-limiting of IP Router
Alert option packets.
If an IP packet contains the IP Router Alert option, but the payload
protocol is not explicitly identified as a Payload of interest by the
router examining the packet, the behavior is not explicitly defined
by [RFC2113]. However, the behavior is implied and, for example, the
definition of RSVP in [RFC2205] assumes that the packet will be
forwarded using normal forwarding based on the destination IP
address. Thus, 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 payload that
is not a payload of interest to that router. The "not passing"
behavior protects the router from DOS attacks using IP Router Alert
packets of a protocol unknown to the router. The "forwarding"
behavior contributes to transparent end to end transport of IP Router
Alert packets (e.g., to facilitate their use by end to end
application).
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6. Security Considerations
This document discusses security risks associated with current usage
of the IP Router Alert Option and associated practices.
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7. IANA Considerations
None.
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8. Contributors
The contributors to this document (in addition to the editors) are:
o Reshad Rahman:
* Cisco Systems
* rrahman@cisco.com
o David Ward:
* Cisco Systems
* wardd@cisco.com
o Ashok Narayanan:
* Cisco Systems
* ashokn@cisco.com
o Adrian Farrell:
* OldDog Consulting
* adrian@olddog.co.uk
o Tony Li:
* tony.li@tony.li
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9. Acknowledgments
We would like to thank Dave Oran, Magnus Westerlund, John Scudder,
Ron Bonica, Ross Callon, Alfred Hines and Carlos Pignataro for their
comments. This document also benefited from discussions with Jukka
Manner and Suresh Krishnan. The discussion about use of the value
field in the IPv4 Router Alert borrowed from a similar discussion in
[I-D.ietf-nsis-ntlp].
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10. References
10.1. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC2113] Katz, D., "IP Router Alert Option", RFC 2113,
February 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
RFC 2711, October 1999.
10.2. Informative References
[I-D.dasmith-mpls-ip-options]
Jaeger, W., Mullooly, J., Scholl, T., and D. Smith,
"Requirements for Label Edge Router Forwarding of IPv4
Option Packets", draft-dasmith-mpls-ip-options-01 (work in
progress), October 2008.
[I-D.ietf-nsis-ntlp]
Schulzrinne, H. and M. Stiemerling, "GIST: General
Internet Signalling Transport", draft-ietf-nsis-ntlp-20
(work in progress), June 2009.
[I-D.ietf-tsvwg-rsvp-l3vpn]
Davie, B., Faucheur, F., and A. Narayanan, "Support for
RSVP in Layer 3 VPNs", draft-ietf-tsvwg-rsvp-l3vpn-02
(work in progress), May 2009.
[I-D.krishnan-ipv6-hopbyhop]
Krishnan, S., "The case against Hop-by-Hop options",
draft-krishnan-ipv6-hopbyhop-03 (work in progress),
July 2009.
[I-D.narayanan-rtg-router-alert-extension]
Narayanan, A., Faucheur, F., Ward, D., and R. Rahman, "IP
Router Alert Option Extension",
draft-narayanan-rtg-router-alert-extension-00 (work in
progress), March 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710,
October 1999.
[RFC2961] Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi, F.,
and S. Molendini, "RSVP Refresh Overhead Reduction
Extensions", RFC 2961, April 2001.
[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations",
RFC 3175, September 2001.
[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, December 2001.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, October 2002.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC4081] Tschofenig, H. and D. Kroeselberg, "Security Threats for
Next Steps in Signaling (NSIS)", RFC 4081, June 2005.
[RFC4286] Haberman, B. and J. Martin, "Multicast Router Discovery",
RFC 4286, December 2005.
[RFC5350] Manner, J. and A. McDonald, "IANA Considerations for the
IPv4 and IPv6 Router Alert Options", RFC 5350,
September 2008.
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Author's Address
Francois Le Faucheur (editor)
Cisco Systems
Greenside, 400 Avenue de Roumanille
Sophia Antipolis 06410
France
Phone: +33 4 97 23 26 19
Email: flefauch@cisco.com
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