draft-ietf-tsvwg-emergency-rsvp-09.txt   draft-ietf-tsvwg-emergency-rsvp-10.txt 
TSVWG F. Le Faucheur TSVWG F. Le Faucheur
Internet-Draft J. Polk Internet-Draft J. Polk
Intended status: Standards Track Cisco Intended status: Standards Track Cisco
Expires: April 20, 2009 K. Carlberg Expires: August 13, 2009 K. Carlberg
G11 G11
October 17, 2008 February 9, 2009
Resource ReSerVation Protovol (RSVP) Extensions for Emergency Services Resource ReSerVation Protovol (RSVP) Extensions for Emergency Services
draft-ietf-tsvwg-emergency-rsvp-09.txt draft-ietf-tsvwg-emergency-rsvp-10.txt
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Abstract Abstract
An Emergency Telecommunications Service (ETS) requires the ability to An Emergency Telecommunications Service (ETS) requires the ability to
provide an elevated probability of session establishment to an provide an elevated probability of session establishment to an
authorized user in times of network congestion (typically, during a authorized user in times of network congestion (typically, during a
crisis). When supported over the Internet Protocol suite, this may crisis). When supported over the Internet Protocol suite, this may
be facilitated through a network layer admission control solution, be facilitated through a network layer admission control solution,
which supports prioritized access to resources (e.g., bandwidth). which supports prioritized access to resources (e.g., bandwidth).
These resources may be explicitly set aside for emergency services, These resources may be explicitly set aside for emergency services,
skipping to change at page 2, line 19 skipping to change at page 3, line 5
The mechanisms defined in this document are applicable to controlled The mechanisms defined in this document are applicable to controlled
environments formed by either a single administrative domain or a set environments formed by either a single administrative domain or a set
of administrative domains that closely coordinate their network of administrative domains that closely coordinate their network
policy and network design. The mechanisms defined in this document policy and network design. The mechanisms defined in this document
can be used for a session whose path spans over such a controlled can be used for a session whose path spans over such a controlled
environment in order to elevate the session establishment probability environment in order to elevate the session establishment probability
through the controlled environment (thereby elevating the end to end through the controlled environment (thereby elevating the end to end
session establishment probability). session establishment probability).
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].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Related Technical Documents . . . . . . . . . . . . . . . 5 1.1. Related Technical Documents . . . . . . . . . . . . . . . 6
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
2. Overview of RSVP extensions and Operations . . . . . . . . . . 6 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 8
2.1. Operations of Admission Priority . . . . . . . . . . . . . 8 3. Overview of RSVP extensions and Operations . . . . . . . . . . 8
3. New Policy Elements . . . . . . . . . . . . . . . . . . . . . 9 3.1. Operations of Admission Priority . . . . . . . . . . . . . 10
3.1. Admission Priority Policy Element . . . . . . . . . . . . 9 4. New Policy Elements . . . . . . . . . . . . . . . . . . . . . 10
3.1.1. Admission Priority Merging Rules . . . . . . . . . . . 11 4.1. Admission Priority Policy Element . . . . . . . . . . . . 11
3.2. Application-Level Resource Priority Policy Element . . . . 12 4.1.1. Admission Priority Merging Rules . . . . . . . . . . . 13
3.2.1. Application-Level Resource Priority Modifying and 4.2. Application-Level Resource Priority Policy Element . . . . 13
Merging Rules . . . . . . . . . . . . . . . . . . . . 13 4.2.1. Application-Level Resource Priority Modifying and
3.3. Default Handling . . . . . . . . . . . . . . . . . . . . . 14 Merging Rules . . . . . . . . . . . . . . . . . . . . 15
4. Security Considerations . . . . . . . . . . . . . . . . . . . 14 4.3. Default Handling . . . . . . . . . . . . . . . . . . . . . 15
4.1. Use of RSVP Authentication between RSVP neighbors . . . . 15 5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
4.2. Use of INTEGRITY object within the POLICY_DATA object . . 15 5.1. Use of RSVP Authentication between RSVP neighbors . . . . 17
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 5.2. Use of INTEGRITY object within the POLICY_DATA object . . 17
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
7.1. Normative References . . . . . . . . . . . . . . . . . . . 19 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.2. Informative References . . . . . . . . . . . . . . . . . . 20 8.1. Normative References . . . . . . . . . . . . . . . . . . . 20
8.2. Informative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Examples of Bandwidth Allocation Model for Appendix A. Examples of Bandwidth Allocation Model for
Admission Priority . . . . . . . . . . . . . . . . . 21 Admission Priority . . . . . . . . . . . . . . . . . 23
A.1. Admission Priority with Maximum Allocation Model (MAM) . . 22 A.1. Admission Priority with Maximum Allocation Model (MAM) . . 24
A.2. Admission Priority with Russian Dolls Model (RDM) . . . . 26 A.2. Admission Priority with Russian Dolls Model (RDM) . . . . 28
A.3. Admission Priority with Priority Bypass Model (PrBM) . . . 29 A.3. Admission Priority with Priority Bypass Model (PrBM) . . . 31
Appendix B. Example Usages of RSVP Extensions . . . . . . . . . . 32 Appendix B. Example Usages of RSVP Extensions . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36
Intellectual Property and Copyright Statements . . . . . . . . . . 36
1. Introduction 1. Introduction
[RFC3689] and [RFC3690] detail requirements for an Emergency [RFC3689] and [RFC3690] detail requirements for an Emergency
Telecommunications Service (ETS), which is an umbrella term Telecommunications Service (ETS), which is an umbrella term
identifying those networks and specific services used to support identifying those networks and specific services used to support
emergency communications. An underlying goal of these documents is emergency communications. An underlying goal of these documents is
to present requirements that elevate the probability of session to present requirements that elevate the probability of session
establishment from an authorized user in times of network congestion establishment from an authorized user in times of network congestion
(presumably because of a crisis condition). In some extreme cases, (presumably because of a crisis condition). In some extreme cases,
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have engineered capacity limits that characterize the maximum load have engineered capacity limits that characterize the maximum load
that can be handled (say, on any given link) for a class of traffic that can be handled (say, on any given link) for a class of traffic
while satisfying the quality of service requirements of that traffic while satisfying the quality of service requirements of that traffic
class. Admission priority may involve setting aside some network class. Admission priority may involve setting aside some network
resources (e.g. bandwidth) out of the engineered capacity limits for resources (e.g. bandwidth) out of the engineered capacity limits for
the emergency services only. Or alternatively, it may involve the emergency services only. Or alternatively, it may involve
allowing the emergency related sessions to seize additional resources allowing the emergency related sessions to seize additional resources
beyond the engineered capacity limits applied to normal sessions. beyond the engineered capacity limits applied to normal sessions.
This document specifies the necessary extensions to support such This document specifies the necessary extensions to support such
admission priority when network layer admission control is performed admission priority when network layer admission control is performed
using the Resource ReSerVation Protovol (RSVP) ([RFC2205]). using the Resource reSerVation Protocol (RSVP) ([RFC2205]).
The mechanisms defined in this document are applicable to controlled The mechanisms defined in this document are applicable to controlled
environments formed by either a single administrative domain or a set environments formed by either a single administrative domain or a set
of administrative domains that closely coordinate their network of administrative domains that closely coordinate their network
policy and network design. The mechanisms defined in this document policy and network design. The mechanisms defined in this document
can be used for a session whose path spans over such a controlled can be used for a session whose path spans over such a controlled
environment in order to elevate the session establishment probability environment in order to elevate the session establishment probability
through the controlled environment (thereby elevating the end to end through the controlled environment (thereby elevating the end to end
session establishment probability). session establishment probability). Let us consider the end to end
environment illustrated in Figure 1 that comprises three separate
administrative domains, each with 2 endpoints and each with Session
Border Controller (SBC) elements ([I-D.ietf-sipping-sbc-funcs])
handling session handover at the domain boundaries.
+----------+ +----------+ +----------+
|Endpoint 1| |Endpoint 3| |Endpoint 5|
+----------+ +----------+ +----------+
| | |
| | |
+----+ +----+ +----+
|SBC | |SBC | |SBC |
,| |--. ,-| |-. ,| |-.
,' +----+ `. ,' +----+ ` . ,' +----+ \
/ ISP \ / ISP \ / ISP `.
/ Domain +----+ +----+ Domain +----+ +----+ Domain \
( A |+----+ |+----+ B |+----+ |+----+ C )
\(Controlled)||SBC |--||SBC |(Controlled)||SBC |--||SBC |(Controlled)/
\ +| | +| | +| | +| | /
`. +----+ +----+ +----+ +----+ .'
'+----+--' `. +----+ .' '--+----+--'
| | '--| |--' | |
|SBC | |SBC | |SBC |
+----+ +----+ +----+
| | |
| | |
+----------+ +----------+ +----------+
|Endpoint 2| |Endpoint 4| |Endpoint 6|
+----------+ +----------+ +----------+
Figure 1: Example End to End Environment
Each domain is operating as a separate controlled environment and may
deploy a given combination of network mechanisms and network policies
within the given domain. For example, ISP Domain A , ISP Domain B
and ISP Domain C may each deploy a different Differentiated Services
([RFC2475]) policy in-between their own SBCs. As another example,
ISP Domain B may elect to deploy MPLS Traffic Engineering ([RFC2702])
within its domain while ISP Domain A and C may not. Similarly, each
domain administrator can make its own decision about whether to
deploy network layer admission control within his domain. If one
domain elects to do so, this can be achieved using RSVP signaling
between the ingress and egress SBC elements of that domain (i.e.,
RSVP signaling operates edge-to-edge and not end-to-end). With this
approach, network layer admission control may be deployed in one
domain regardless of whether it is deployed in the other domains on
the end to end path of sessions. Also, deploying network layer
admission control within one domain does not require any
collaboration or even pre-agreement with other domains since it
operates transparently from other domains (the only externally
visible impact might be on quality of service offered to the sessions
that transit through that domain). The mechanisms defined in this
document are applicable within a controlled environment that elects
to deploy network layer admission control using RSVP and handles
emergency communications. For example, ISP domain A and ISP domain C
may elect to use RSVP and the extensions defined in this document
within their respective domain while ISP domain B may not deploy
network layer admission control within his domain. In that case, a
session between Endpoint 1 and Endpoint 6 would benefit from network
layer admission control and resource reservation through domain A
network and domain C network. If that session is an emergency
session, the extensions defined in this document increase the
probability of admission of that particular session through domain A
and domain C, thereby increasing the end-to-end session establishment
probability.
As another example, all three domains shown in Figure 1 may elect to
deploy RSVP admission control and the extensions defined in this
document within their own domain. This would ensure that emergency
sessions are protected by resource reservation and elevated session
establishment probability through every domain on the end to end
path. But even in that case, RSVP signaling and the extensions
defined in this document need not operate end-to-end; rather they are
expected to operate edge-to-edge within each domain only (with RSVP
being terminated by the egress SBC on the egress edge of one domain
and regenerated by the ingress SBC on the ingress edge of the next
domain).
IP telephony "calls" are one form of "sessions" that can benefit from IP telephony "calls" are one form of "sessions" that can benefit from
the elevated session establishment probability discussed in this the elevated session establishment probability discussed in this
document. Video over IP and Instant Messaging are other examples. document. Video over IP and Instant Messaging are other examples.
For the sake of generality, we use the term "session" throughout this For the sake of generality, we use the term "session" throughout this
document to refer to any type of session. document to refer to any type of session.
1.1. Related Technical Documents 1.1. Related Technical Documents
[RFC4542] is patterned after [ITU.I.225] and describes an example of [RFC4542] is patterned after [ITU.I.225] and describes an example of
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o Local Policy Decision Point (LPDP): PDP local to the network o Local Policy Decision Point (LPDP): PDP local to the network
element. element.
o Policy Enforcement Point (PEP): The point where the policy o Policy Enforcement Point (PEP): The point where the policy
decisions are actually enforced. decisions are actually enforced.
o Policy Ignorant Node (PIN): A network element that does not o Policy Ignorant Node (PIN): A network element that does not
explicitly support policy control using the mechanisms defined in explicitly support policy control using the mechanisms defined in
[RFC2753]. [RFC2753].
2. Overview of RSVP extensions and Operations 2. 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].
3. Overview of RSVP extensions and Operations
Let us consider the case where a session requiring ETS type service Let us consider the case where a session requiring ETS type service
is to be established, and more specifically that the preference to be is to be established, and more specifically that the preference to be
granted to this session is in terms of network layer "admission granted to this session is in terms of network layer "admission
priority" (as opposed to preference granted through preemption of priority" (as opposed to preference granted through preemption of
existing sessions). By "admission priority" we mean allowing that existing sessions). By "admission priority" we mean allowing that
priority session to seize network layer resources from the engineered priority session to seize network layer resources from the engineered
capacity that have been set-aside and not made available to normal capacity that have been set-aside and not made available to normal
sessions, or alternatively by allowing that session to seize sessions, or alternatively by allowing that session to seize
additional resources beyond the engineered capacity limits applied to additional resources beyond the engineered capacity limits applied to
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the RSVP message allows this application level requirement to be the RSVP message allows this application level requirement to be
mapped/remapped into a different RSVP "admission priority" at every mapped/remapped into a different RSVP "admission priority" at every
administrative domain boundary based on the policy applicable in that administrative domain boundary based on the policy applicable in that
domain. In a typical model (see [RFC2753]) where PDPs control PEPs domain. In a typical model (see [RFC2753]) where PDPs control PEPs
at the periphery of the policy domain (e.g., in border routers), PDPs at the periphery of the policy domain (e.g., in border routers), PDPs
would interpret the RSVP Application-Level Resource-Priority Policy would interpret the RSVP Application-Level Resource-Priority Policy
Element and map the requirement of the emergency session into an RSVP Element and map the requirement of the emergency session into an RSVP
"admission priority" level. Then, PDPs would convey this information "admission priority" level. Then, PDPs would convey this information
inside the new Admission Priority Policy Element defined in this inside the new Admission Priority Policy Element defined in this
document. This way, the RSVP admission priority can be communicated document. This way, the RSVP admission priority can be communicated
to downstream PEPs (ie RSVP Routers) of the same policy domain, which to downstream PEPs (i.e. RSVP Routers) of the same policy domain,
have LPDPs but no controlling PDP. In turn, this means the necessary which have LPDPs but no controlling PDP. In turn, this means the
RSVP Admission priority can be enforced at every RSVP hop, including necessary RSVP Admission priority can be enforced at every RSVP hop,
all the (many) hops which do not have any understanding of including all the (many) hops which do not have any understanding of
Application-Level Resource-Priority semantics. Application-Level Resource-Priority semantics.
As an example of operation across multiple administrative domains, a As an example of operation across multiple administrative domains, a
first domain might decide to provide network layer admission priority first domain might decide to provide network layer admission priority
to sessions of a given Application Level Resource Priority and map it to sessions of a given Application Level Resource Priority and map it
into a high RSVP admission control priority inside the Admission into a high RSVP admission control priority inside the Admission
Priority Policy Element; while a second domain may decide to not Priority Policy Element; while a second domain may decide to not
provide admission priority to sessions of this same Application Level provide admission priority to sessions of this same Application Level
Resource Priority and hence map it into a low RSVP admission control Resource Priority and hence map it into a low RSVP admission control
priority. priority.
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information can then be encoded inside the Preemption Priority Policy information can then be encoded inside the Preemption Priority Policy
Element of [RFC3181] and thus, can be taken into account at every Element of [RFC3181] and thus, can be taken into account at every
RSVP-enabled network hop as discussed [RFC4542]. Appendix B provides RSVP-enabled network hop as discussed [RFC4542]. Appendix B provides
examples of various hypothetical policies for emergency session examples of various hypothetical policies for emergency session
handling, some of them involving admission priority, some of them handling, some of them involving admission priority, some of them
involving both admission priority and preemption priority. Appendix involving both admission priority and preemption priority. Appendix
B also identifies how the Application-Level Resource Priority need to B also identifies how the Application-Level Resource Priority need to
be mapped into RSVP policy elements by the PDPs to realize these be mapped into RSVP policy elements by the PDPs to realize these
policies. policies.
2.1. Operations of Admission Priority 3.1. Operations of Admission Priority
The RSVP Admission Priority policy element defined in this document The RSVP Admission Priority policy element defined in this document
allows admission bandwidth to be allocated preferentially to an allows admission bandwidth to be allocated preferentially to an
authorized priority service. Multiple models of bandwidth allocation authorized priority service. Multiple models of bandwidth allocation
MAY be used to that end. MAY be used to that end.
A number of bandwidth allocation models have been defined in the IETF A number of bandwidth allocation models have been defined in the IETF
for allocation of bandwidth across different classes of traffic for allocation of bandwidth across different classes of traffic
trunks in the context of Diffserv-aware MPLS Traffic Engineering. trunks in the context of Diffserv-aware MPLS Traffic Engineering.
Those include the Maximum Allocation Model (MAM) defined in Those include the Maximum Allocation Model (MAM) defined in
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models described and illustrated in Appendix A are only informative models described and illustrated in Appendix A are only informative
and do not represent a recommended course of action. and do not represent a recommended course of action.
We can see in these examples, that the RSVP Admission Priority may We can see in these examples, that the RSVP Admission Priority may
effectively influence the fundamental admission control decision of effectively influence the fundamental admission control decision of
RSVP (for example by determining which bandwidth pool is to be used RSVP (for example by determining which bandwidth pool is to be used
by RSVP for performing its fundamental bandwidth allocation). In by RSVP for performing its fundamental bandwidth allocation). In
that sense, we observe that the policy control and admission control that sense, we observe that the policy control and admission control
are not separate logics but instead somewhat blended. are not separate logics but instead somewhat blended.
3. New Policy Elements 4. New Policy Elements
The Framework document for policy-based admission control [RFC2753] The Framework document for policy-based admission control [RFC2753]
describes the various components that participate in policy decision describes the various components that participate in policy decision
making (i.e., PDP, PEP and LPDP). making (i.e., PDP, PEP and LPDP).
As described in section 2 of the present document, the Application- As described in section 2 of the present document, the Application-
Level Resource Priority Policy Element and the Admission Priority Level Resource Priority Policy Element and the Admission Priority
Policy Element serve different roles in this framework: Policy Element serve different roles in this framework:
o the Application-Level Resource Priority Policy Element conveys o the Application-Level Resource Priority Policy Element conveys
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The POLICY_DATA object contains one or more of Policy Elements, each The POLICY_DATA object contains one or more of Policy Elements, each
representing a different (and perhaps orthogonal) policy. As an representing a different (and perhaps orthogonal) policy. As an
example, [RFC3181] specifies the Preemption Priority Policy Element. example, [RFC3181] specifies the Preemption Priority Policy Element.
This document defines two new Policy Elements called: This document defines two new Policy Elements called:
o the Admission Priority Policy Element o the Admission Priority Policy Element
o the Application-Level Resource Priority Policy Element o the Application-Level Resource Priority Policy Element
3.1. Admission Priority Policy Element 4.1. Admission Priority Policy Element
The format of the Admission Priority policy element is as shown in The format of the Admission Priority policy element is as shown in
Figure 1: Figure 2:
0 0 0 1 1 2 2 3 0 0 0 1 1 2 2 3
0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1 0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1
+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+
| Length | P-Type = ADMISSION_PRI | | Length | P-Type = ADMISSION_PRI |
+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+
| Flags | M. Strategy | Error Code | Reserved | | Flags | M. Strategy | Error Code | Reserved |
+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+
| Reserved |Adm. Priority| | Reserved |Adm. Priority|
+---------------------------+---------------------------+ +---------------------------+---------------------------+
Figure 1: Admission Priority Policy Element Figure 2: Admission Priority Policy Element
where: where:
o Length: 16 bits o Length: 16 bits
* Always 12. The overall length of the policy element, in bytes. * Always 12. The overall length of the policy element, in bytes.
o P-Type: 16 bits o P-Type: 16 bits
* ADMISSION_PRI = To be allocated by IANA (see "IANA * ADMISSION_PRI = To be allocated by IANA (see "IANA
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Note that the Admission Priority Policy Element does NOT indicate Note that the Admission Priority Policy Element does NOT indicate
that this RSVP reservation is to preempt any other RSVP reservation. that this RSVP reservation is to preempt any other RSVP reservation.
If a priority session justifies both admission priority and If a priority session justifies both admission priority and
preemption priority, the corresponding RSVP reservation needs to preemption priority, the corresponding RSVP reservation needs to
carry both an Admission Priority Policy Element and a Preemption carry both an Admission Priority Policy Element and a Preemption
Priority Policy Element. The Admission Priority and Preemption Priority Policy Element. The Admission Priority and Preemption
Priority are handled by LPDPs and PEPs as separate mechanisms. They Priority are handled by LPDPs and PEPs as separate mechanisms. They
can be used one without the other, or they can be used both in can be used one without the other, or they can be used both in
combination. combination.
3.1.1. Admission Priority Merging Rules 4.1.1. Admission Priority Merging Rules
This section discusses alternatives for dealing with RSVP admission This section discusses alternatives for dealing with RSVP admission
priority in case of merging of reservations. As merging is only priority in case of merging of reservations. As merging is only
applicable to multicast, this section also only applies to multicast applicable to multicast, this section also only applies to multicast
sessions. sessions.
The rules for merging Admission Priority Policy Elements are defined The rules for merging Admission Priority Policy Elements are defined
by the value encoded inside the Merge Strategy field in accordance by the value encoded inside the Merge Strategy field in accordance
with the corresponding IANA registry. The merge strategies (and with the corresponding IANA registry. The merge strategies (and
associated values) defined by the present document are the same as associated values) defined by the present document are the same as
those defined in [RFC3181] for merging Preemption Priority Policy those defined in [RFC3181] for merging Preemption Priority Policy
Elements (see "IANA Considerations" section). Elements (see "IANA Considerations" section).
The only difference with [RFC3181] is that this document does not The only difference with [RFC3181] is that this document does not
recommend any merge strategies for Admission Priority, while recommend any merge strategies for Admission Priority, while
[RFC3181] recommends the first of these merge strategies for [RFC3181] recommends the first of these merge strategies for
Preemption Priority. Note that with the Admission Priority (as is Preemption Priority. Note that with the Admission Priority (as is
the case with the Preemption Priority), "Take highest priority" the case with the Preemption Priority), "Take highest priority"
translates into "take the highest numerical value". translates into "take the highest numerical value".
3.2. Application-Level Resource Priority Policy Element 4.2. Application-Level Resource Priority Policy Element
The format of the Application-Level Resource Priority policy element The format of the Application-Level Resource Priority policy element
is as shown in Figure 2: is as shown in Figure 3:
0 0 0 1 1 2 2 3 0 0 0 1 1 2 2 3
0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1 0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1
+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+
| Length | P-Type = APP_RESOURCE_PRI | | Length | P-Type = APP_RESOURCE_PRI |
+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+
// ALRP List // // ALRP List //
+---------------------------+---------------------------+ +---------------------------+---------------------------+
Figure 2: Application-Level Resource Priority Policy Element Figure 3: Application-Level Resource Priority Policy Element
where: where:
o Length: o Length:
* The length of the policy element (including the Length and * The length of the policy element (including the Length and
P-Type) is in number of octets (MUST be a multiple of 4) and P-Type) is in number of octets (MUST be a multiple of 4) and
indicates the end of the ALRP list. indicates the end of the ALRP list.
o P-Type: 16 bits o P-Type: 16 bits
* APP_RESOURCE_PRI = To be allocated by IANA (see "IANA * APP_RESOURCE_PRI = To be allocated by IANA (see "IANA
Considerations" section) Considerations" section)
o ALRP List: o ALRP List:
* List of ALRP where each ALRP is encoded as shown in Figure 3. * List of ALRP where each ALRP is encoded as shown in Figure 4.
ALRP: ALRP:
0 0 0 1 1 2 2 3 0 0 0 1 1 2 2 3
0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1 0 . . . 7 8 . . . 5 6 . . . 3 4 . . . 1
+---------------------------+-------------+-------------+ +---------------------------+-------------+-------------+
| ALRP Namespace | Reserved |ALRP Priority| | ALRP Namespace | Reserved |ALRP Priority|
+---------------------------+---------------------------+ +---------------------------+---------------------------+
Figure 3: Application-Level Resource Priority Figure 4: Application-Level Resource Priority
where: where:
o ALRP Namespace (Application-Level Resource Priority Namespace): 16 o ALRP Namespace (Application-Level Resource Priority Namespace): 16
bits (unsigned) bits (unsigned)
* Contains a numerical value identifying the namespace of the * Contains a numerical value identifying the namespace of the
application-level resource priority. This value is encoded as application-level resource priority. This value is encoded as
per the "Resource-Priority Namespaces" IANA registry. (See per the "Resource-Priority Namespaces" IANA registry. (See
IANA Considerations section for the request to IANA to extend IANA Considerations section for the request to IANA to extend
skipping to change at page 13, line 39 skipping to change at page 15, line 19
o ALRP Priority: (Application-Level Resource Priority Priority): 8 o ALRP Priority: (Application-Level Resource Priority Priority): 8
bits (unsigned) bits (unsigned)
* Contains the priority value within the namespace of the * Contains the priority value within the namespace of the
application-level resource priority. This value is encoded as application-level resource priority. This value is encoded as
per the "Resource-Priority Priority-Value" IANA registry. (See per the "Resource-Priority Priority-Value" IANA registry. (See
IANA Considerations section for the request to IANA to extend IANA Considerations section for the request to IANA to extend
the registry to include this numerical value). the registry to include this numerical value).
3.2.1. Application-Level Resource Priority Modifying and Merging Rules 4.2.1. Application-Level Resource Priority Modifying and Merging Rules
When POLICY_DATA objects are protected by integrity, LPDPs should not When POLICY_DATA objects are protected by integrity, LPDPs should not
attempt to modify them. They MUST be forwarded as-is to ensure their attempt to modify them. They MUST be forwarded as-is to ensure their
security envelope is not invalidated. security envelope is not invalidated.
In case of multicast, when POLICY_DATA objects are not protected by In case of multicast, when POLICY_DATA objects are not protected by
integrity, LPDPs MAY merge incoming Application-Level Resource integrity, LPDPs MAY merge incoming Application-Level Resource
Priority elements to reduce their size and number. When they do Priority elements to reduce their size and number. When they do
merge those, LPDPs MUST do so according to the following rule: merge those, LPDPs MUST do so according to the following rule:
o The ALRP List in the outgoing APP_RESOURCE_PRI element MUST list o The ALRP List in the outgoing APP_RESOURCE_PRI element MUST list
all the ALRPs appearing in the ALRP List of an incoming all the ALRPs appearing in the ALRP List of an incoming
APP_RESOURCE_PRI element. A given ALRP MUST NOT appear more than APP_RESOURCE_PRI element. A given ALRP MUST NOT appear more than
once. In other words, the outgoing ALRP List is the union of the once. In other words, the outgoing ALRP List is the union of the
incoming ALRP Lists that are merged. incoming ALRP Lists that are merged.
As merging is only applicable to Multicast, this rule only applies to As merging is only applicable to Multicast, this rule only applies to
Multicast sessions. Multicast sessions.
3.3. Default Handling 4.3. Default Handling
As specified in section 4.2 of [RFC2750], Policy Ignorant Nodes As specified in section 4.2 of [RFC2750], Policy Ignorant Nodes
(PINs) implement a default handling of POLICY_DATA objects ensuring (PINs) implement a default handling of POLICY_DATA objects ensuring
that those objects can traverse PIN nodes in transit from one PEP to that those objects can traverse PIN nodes in transit from one PEP to
another. This applies to the situations where POLICY_DATA objects another. This applies to the situations where POLICY_DATA objects
contain the Admission Priority Policy Element and the ALRP Policy contain the Admission Priority Policy Element and the ALRP Policy
Element specified in this document, so that those can traverse PIN Element specified in this document, so that those can traverse PIN
nodes. nodes.
Section 4.2 of [RFC2750] also defines a similar default behavior for Section 4.2 of [RFC2750] also defines a similar default behavior for
policy-capable nodes that do not recognized a particular Policy policy-capable nodes that do not recognized a particular Policy
Element. This applies to the Admission Priority Policy Element and Element. This applies to the Admission Priority Policy Element and
the ALRP Policy Element specified in this document, so that those can the ALRP Policy Element specified in this document, so that those can
traverse policy-capable nodes that do not support this document. traverse policy-capable nodes that do not support this document.
4. Security Considerations 5. Security Considerations
As this document defines extensions to RSVP, the security As this document defines extensions to RSVP, the security
considerations of RSVP apply. Those are discussed in [RFC2205], considerations of RSVP apply. Those are discussed in [RFC2205],
[RFC4230] and [I-D.ietf-tsvwg-rsvp-security-groupkeying]. [RFC4230] and [I-D.ietf-tsvwg-rsvp-security-groupkeying].
A subset of RSVP messages are signaled with the Router Alert Option A subset of RSVP messages are signaled with the Router Alert Option
(RAO)([RFC2113],[RFC2711]). However, some network administrators (RAO)([RFC2113],[RFC2711]). However, some network administrators
activate mechanisms at the edge of their administrative domain to activate mechanisms at the edge of their administrative domain to
protect against potential Denial Of Service (DOS) attacks associated protect against potential Denial Of Service (DOS) attacks associated
with RAO. This may include hiding of the RAO to downstream interior with RAO. This may include hiding of the RAO to downstream interior
skipping to change at page 15, line 14 skipping to change at page 16, line 41
[I-D.ietf-tsvwg-rsvp-l3vpn]). We observe that the risks and security [I-D.ietf-tsvwg-rsvp-l3vpn]). We observe that the risks and security
measures associated with processing of RAO messages at an measures associated with processing of RAO messages at an
administrative domain edge are fundamentally similar to those administrative domain edge are fundamentally similar to those
involved with other forms of control plane interactions allowed at involved with other forms of control plane interactions allowed at
administrative domain edges, such as routing or multicast routing administrative domain edges, such as routing or multicast routing
interactions allowed between a customer and his Internet Service interactions allowed between a customer and his Internet Service
Provider, MPLS VPN ( [RFC4364] Service Provider , [RFC4659]) or MPLS Provider, MPLS VPN ( [RFC4364] Service Provider , [RFC4659]) or MPLS
MVPN ([I-D.ietf-l3vpn-2547bis-mcast]) Service Provider. MVPN ([I-D.ietf-l3vpn-2547bis-mcast]) Service Provider.
The ADMISSION_PRI and APP_RESOURCE_PRI Policy Elements defined in The ADMISSION_PRI and APP_RESOURCE_PRI Policy Elements defined in
this doocument are signaled by RSVP through encapsulation in a Policy this document are signaled by RSVP through encapsulation in a Policy
Data object as defined in [RFC2750]. Therefore, like any other Data object as defined in [RFC2750]. Therefore, like any other
Policy Elements, their integrity can be protected as discussed in Policy Elements, their integrity can be protected as discussed in
section 6 of [RFC2750] by two optional security mechanisms. The section 6 of [RFC2750] by two optional security mechanisms. The
first mechanism relies on RSVP Authentication as specified in first mechanism relies on RSVP Authentication as specified in
[RFC2747] and [RFC3097] to provide a chain of trust when all RSVP [RFC2747] and [RFC3097] to provide a chain of trust when all RSVP
nodes are policy capable. With this mechanism, the INTEGRITY object nodes are policy capable. With this mechanism, the INTEGRITY object
is carried inside RSVP messages. The second mechanism relies on the is carried inside RSVP messages. The second mechanism relies on the
INTEGRITY object within the POLICY_DATA object to guarantee integrity INTEGRITY object within the POLICY_DATA object to guarantee integrity
between RSVP Policy Enforcement Points (PEPs) that are not RSVP between RSVP Policy Enforcement Points (PEPs) that are not RSVP
neighbors. neighbors.
4.1. Use of RSVP Authentication between RSVP neighbors 5.1. Use of RSVP Authentication between RSVP neighbors
This mechanism can be used between RSVP neighbors that are policy This mechanism can be used between RSVP neighbors that are policy
capable. The RSVP neighbors use shared keys to compute the capable. The RSVP neighbors use shared keys to compute the
cryptographic signature of the RSVP message. cryptographic signature of the RSVP message.
[I-D.ietf-tsvwg-rsvp-security-groupkeying] discusses key types, key [I-D.ietf-tsvwg-rsvp-security-groupkeying] discusses key types, key
provisioning methods as well as their respective applicability. provisioning methods as well as their respective applicability.
4.2. Use of INTEGRITY object within the POLICY_DATA object 5.2. Use of INTEGRITY object within the POLICY_DATA object
The INTEGRITY object within the POLICY_DATA object can be used to The INTEGRITY object within the POLICY_DATA object can be used to
guarantee integrity between non-neighboring RSVP PEPs. guarantee integrity between non-neighboring RSVP PEPs.
Details for computation of the content of the INTEGRITY object can be Details for computation of the content of the INTEGRITY object can be
found in Appendix B of [RFC2750]. This states that the Policy found in Appendix B of [RFC2750]. This states that the Policy
Decision Point (PDP), at its discretion, and based on destination Decision Point (PDP), at its discretion, and based on destination
PEP/PDP or other criteria, selects an Authentication Key and the hash PEP/PDP or other criteria, selects an Authentication Key and the hash
algorithm to be used. Keys to be used between PDPs can be algorithm to be used. Keys to be used between PDPs can be
distributed manually or via standard key management protocol for distributed manually or via standard key management protocol for
skipping to change at page 16, line 16 skipping to change at page 17, line 44
conceptually similar to the use of key shared across multiple RSVP conceptually similar to the use of key shared across multiple RSVP
neighbors discussed in [I-D.ietf-tsvwg-rsvp-security-groupkeying]. neighbors discussed in [I-D.ietf-tsvwg-rsvp-security-groupkeying].
We observe also that this issue may not exist in some deployment We observe also that this issue may not exist in some deployment
scenarios where a single (or low number of) PDP is used to control scenarios where a single (or low number of) PDP is used to control
all the PEPs of a region (such as an administrative domain). In such all the PEPs of a region (such as an administrative domain). In such
scenarios, it may be easy for a PDP to determine what is the next hop scenarios, it may be easy for a PDP to determine what is the next hop
PDP, even when the next hop PEP is not known, simply by determining PDP, even when the next hop PEP is not known, simply by determining
what is the next region that will be traversed (say based on the what is the next region that will be traversed (say based on the
destination address). destination address).
5. IANA Considerations 6. IANA Considerations
As specified in [RFC2750], Standard RSVP Policy Elements (P-type As specified in [RFC2750], Standard RSVP Policy Elements (P-type
values) are to be assigned by IANA as per "IETF Consensus" policy values) are to be assigned by IANA as per "IETF Consensus" policy
following the policies outlined in [RFC2434] (this policy is now following the policies outlined in [RFC2434] (this policy is now
called "IETF Review" as per [RFC5226]) . called "IETF Review" as per [RFC5226]) .
IANA needs to allocate two P-Types from the Standard RSVP Policy IANA needs to allocate two P-Types from the Standard RSVP Policy
Element range: Element range:
o one P-Type to the Admission Priority Policy Element o one P-Type to the Admission Priority Policy Element
skipping to change at page 18, line 39 skipping to change at page 20, line 20
A numerical value should be allocated immediately by IANA to all A numerical value should be allocated immediately by IANA to all
existing priority. Then, in the future, IANA should automatically existing priority. Then, in the future, IANA should automatically
allocate a numerical value to any new namespace added to the allocate a numerical value to any new namespace added to the
registry. The numerical value must be unique within each namespace. registry. The numerical value must be unique within each namespace.
For the initial allocation, within each namespace, values should be For the initial allocation, within each namespace, values should be
allocated in decreasing order ending with 0 (so that the greatest allocated in decreasing order ending with 0 (so that the greatest
priority is always allocated value 0). For example, in the drsn priority is always allocated value 0). For example, in the drsn
namespace, "routine" would be allocated numerical value 5 and "flash- namespace, "routine" would be allocated numerical value 5 and "flash-
override-override" would be allocated numerical value 0. override-override" would be allocated numerical value 0.
6. Acknowledgments 7. Acknowledgments
We would like to thank An Nguyen for his encouragement to address We would like to thank An Nguyen for his encouragement to address
this topic and ongoing comments. Also, this document borrows heavily this topic and ongoing comments. Also, this document borrows heavily
from some of the work of S. Herzog on Preemption Priority Policy from some of the work of S. Herzog on Preemption Priority Policy
Element [RFC3181]. Dave Oran and Janet Gunn provided useful input Element [RFC3181]. Dave Oran and Janet Gunn provided useful input
into this document. Thanks to Magnus Westerlund, Cullen Jennings and into this document. Thanks to Magnus Westerlund, Cullen Jennings and
Ross Callon for helping clarify applicability of the mechanisms Ross Callon for helping clarify applicability of the mechanisms
defined in this document. defined in this document.
7. References 8. References
7.1. Normative References 8.1. Normative References
[RFC2113] Katz, D., "IP Router Alert Option", RFC 2113, [RFC2113] Katz, D., "IP Router Alert Option", RFC 2113,
February 1997. February 1997.
[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.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997. Functional Specification", RFC 2205, September 1997.
skipping to change at page 20, line 5 skipping to change at page 21, line 31
June 2002. June 2002.
[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource [RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
Priority for the Session Initiation Protocol (SIP)", Priority for the Session Initiation Protocol (SIP)",
RFC 4412, February 2006. RFC 4412, February 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
7.2. Informative References 8.2. Informative References
[I-D.dasmith-mpls-ip-options] [I-D.dasmith-mpls-ip-options]
Jaeger, W., Mullooly, J., Scholl, T., and D. Smith, Jaeger, W., Mullooly, J., Scholl, T., and D. Smith,
"Requirements for Label Edge Router Forwarding of IPv4 "Requirements for Label Edge Router Forwarding of IPv4
Option Packets", draft-dasmith-mpls-ip-options-01 (work in Option Packets", draft-dasmith-mpls-ip-options-01 (work in
progress), October 2008. progress), October 2008.
[I-D.ietf-dime-diameter-qos] [I-D.ietf-dime-diameter-qos]
Sun, D., McCann, P., Tschofenig, H., Tsou, T., Doria, A., Sun, D., McCann, P., Tschofenig, H., Tsou, T., Doria, A.,
and G. Zorn, "Diameter Quality of Service Application", and G. Zorn, "Diameter Quality of Service Application",
draft-ietf-dime-diameter-qos-06 (work in progress), draft-ietf-dime-diameter-qos-07 (work in progress),
July 2008. December 2008.
[I-D.ietf-dime-qos-parameters] [I-D.ietf-dime-qos-parameters]
Korhonen, J. and H. Tschofenig, "Quality of Service Korhonen, J., Tschofenig, H., and E. Davies, "Quality of
Parameters for Usage with the AAA Framework", Service Parameters for Usage with Diameter",
draft-ietf-dime-qos-parameters-06 (work in progress), draft-ietf-dime-qos-parameters-09 (work in progress),
May 2008. January 2009.
[I-D.ietf-l3vpn-2547bis-mcast] [I-D.ietf-l3vpn-2547bis-mcast]
Aggarwal, R., Bandi, S., Cai, Y., Morin, T., Rekhter, Y., Aggarwal, R., Bandi, S., Cai, Y., Morin, T., Rekhter, Y.,
Rosen, E., Wijnands, I., and S. Yasukawa, "Multicast in Rosen, E., Wijnands, I., and S. Yasukawa, "Multicast in
MPLS/BGP IP VPNs", draft-ietf-l3vpn-2547bis-mcast-07 (work MPLS/BGP IP VPNs", draft-ietf-l3vpn-2547bis-mcast-07 (work
in progress), July 2008. in progress), July 2008.
[I-D.ietf-nsis-qspec] [I-D.ietf-nsis-qspec]
Ash, G., Bader, A., Kappler, C., and D. Oran, "QoS NSLP Bader, A., Kappler, C., and D. Oran, "QoS NSLP QSPEC
QSPEC Template", draft-ietf-nsis-qspec-20 (work in Template", draft-ietf-nsis-qspec-21 (work in progress),
progress), April 2008. November 2008.
[I-D.ietf-sipping-sbc-funcs]
Hautakorpi, J., Camarillo, G., Penfield, B., Hawrylyshen,
A., and M. Bhatia, "Requirements from SIP (Session
Initiation Protocol) Session Border Control Deployments",
draft-ietf-sipping-sbc-funcs-08 (work in progress),
January 2009.
[I-D.ietf-tsvwg-rsvp-l3vpn] [I-D.ietf-tsvwg-rsvp-l3vpn]
Davie, B., Faucheur, F., and A. Narayanan, "Support for Davie, B., Faucheur, F., and A. Narayanan, "Support for
RSVP in Layer 3 VPNs", draft-ietf-tsvwg-rsvp-l3vpn-00 RSVP in Layer 3 VPNs", draft-ietf-tsvwg-rsvp-l3vpn-01
(work in progress), July 2008. (work in progress), November 2008.
[I-D.ietf-tsvwg-rsvp-security-groupkeying] [I-D.ietf-tsvwg-rsvp-security-groupkeying]
Behringer, M. and F. Faucheur, "Applicability of Keying Behringer, M. and F. Faucheur, "Applicability of Keying
Methods for RSVP Security", Methods for RSVP Security",
draft-ietf-tsvwg-rsvp-security-groupkeying-01 (work in draft-ietf-tsvwg-rsvp-security-groupkeying-02 (work in
progress), July 2008. progress), November 2008.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, September 1999.
[RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework [RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework
for Policy-based Admission Control", RFC 2753, for Policy-based Admission Control", RFC 2753,
January 2000. January 2000.
[RFC3182] Yadav, S., Yavatkar, R., Pabbati, R., Ford, P., Moore, T., [RFC3182] Yadav, S., Yavatkar, R., Pabbati, R., Ford, P., Moore, T.,
Herzog, S., and R. Hess, "Identity Representation for Herzog, S., and R. Hess, "Identity Representation for
RSVP", RFC 3182, October 2001. RSVP", RFC 3182, October 2001.
[RFC3312] Camarillo, G., Marshall, W., and J. Rosenberg, [RFC3312] Camarillo, G., Marshall, W., and J. Rosenberg,
skipping to change at page 22, line 46 skipping to change at page 24, line 39
neered .or.or. | | . neered .or.or. | | .
. . . | | . . . . | | .
Capacity. . . | | . Capacity. . . | | .
v . . | | v v . . | | v
. . |--------------| --- . . |--------------| ---
v . | | ^ v . | | ^
. | | . Bandwidth available for . | | . Bandwidth available for
v | | v priority use v | | v priority use
------------------------- -------------------------
Figure 4: MAM Bandwidth Allocation Figure 5: MAM Bandwidth Allocation
Figure 4 shows a link within a routed network conforming to this Figure 5 shows a link within a routed network conforming to this
document. On this link are two amounts of bandwidth available to two document. On this link are two amounts of bandwidth available to two
types of traffic: non-priority and priority. types of traffic: non-priority and priority.
If the non-priority traffic load reaches the maximum bandwidth If the non-priority traffic load reaches the maximum bandwidth
available for non-priority, no additional non-priority sessions can available for non-priority, no additional non-priority sessions can
be accepted even if the bandwidth reserved for priority traffic is be accepted even if the bandwidth reserved for priority traffic is
not currently fully utilized. not currently fully utilized.
With the Maximum Allocation Model, in the case where the priority With the Maximum Allocation Model, in the case where the priority
load reaches the maximum bandwidth reserved for priority sessions, no load reaches the maximum bandwidth reserved for priority sessions, no
additional priority sessions can be accepted. additional priority sessions can be accepted.
As illustrated in Figure 4, an operator may map the MAM model onto As illustrated in Figure 5, an operator may map the MAM model onto
the Engineered Capacity limits according to different policies. At the Engineered Capacity limits according to different policies. At
one extreme, where the proportion of priority traffic is reliably one extreme, where the proportion of priority traffic is reliably
known to be fairly small at all times and where there may be some known to be fairly small at all times and where there may be some
safety margin factored in the engineered capacity limits, the safety margin factored in the engineered capacity limits, the
operator may decide to configure the bandwidth available for non- operator may decide to configure the bandwidth available for non-
priority use to the full engineered capacity limits; effectively priority use to the full engineered capacity limits; effectively
allowing the priority traffic to ride within the safety margin of allowing the priority traffic to ride within the safety margin of
this engineered capacity. This policy can be seen as an economically this engineered capacity. This policy can be seen as an economically
attractive approach as all of the engineered capacity is made attractive approach as all of the engineered capacity is made
available to non-priority sessions. This policy is illustrated as available to non-priority sessions. This policy is illustrated as
(1) in Figure 4. As an example, if the engineered capacity limit on (1) in Figure 5. As an example, if the engineered capacity limit on
a given link is X, the operator may configure the bandwidth available a given link is X, the operator may configure the bandwidth available
to non-priority traffic to X, and the bandwidth available to priority to non-priority traffic to X, and the bandwidth available to priority
traffic to 5% of X. At the other extreme, where the proportion of traffic to 5% of X. At the other extreme, where the proportion of
priority traffic may be significant at times and the engineered priority traffic may be significant at times and the engineered
capacity limits are very tight, the operator may decide to configure capacity limits are very tight, the operator may decide to configure
the bandwidth available to non-priority traffic and the bandwidth the bandwidth available to non-priority traffic and the bandwidth
available to priority traffic such that their sum is equal to the available to priority traffic such that their sum is equal to the
engineered capacity limits. This guarantees that the total load engineered capacity limits. This guarantees that the total load
across non-priority and priority traffic is always below the across non-priority and priority traffic is always below the
engineered capacity and, in turn, guarantees there will never be any engineered capacity and, in turn, guarantees there will never be any
QoS degradation. However, this policy is less attractive QoS degradation. However, this policy is less attractive
economically as it prevents non-priority sessions from using the full economically as it prevents non-priority sessions from using the full
engineered capacity, even when there is no or little priority load, engineered capacity, even when there is no or little priority load,
which is the majority of time. This policy is illustrated as (3) in which is the majority of time. This policy is illustrated as (3) in
Figure 4. As an example, if the engineered capacity limit on a given Figure 5. As an example, if the engineered capacity limit on a given
link is X, the operator may configure the bandwidth available to non- link is X, the operator may configure the bandwidth available to non-
priority traffic to 95% of X, and the bandwidth available to priority priority traffic to 95% of X, and the bandwidth available to priority
traffic to 5% of X. Of course, an operator may also strike a balance traffic to 5% of X. Of course, an operator may also strike a balance
anywhere in between these two approaches. This policy is illustrated anywhere in between these two approaches. This policy is illustrated
as (2) in Figure 4. as (2) in Figure 5.
Figure 5 shows some of the non-priority capacity of this link being Figure 6 shows some of the non-priority capacity of this link being
used. used.
----------------------- -----------------------
^ ^ ^ | | ^ ^ ^ ^ | | ^
. . . | | . . . . | | .
Total . . . | | . Bandwidth Total . . . | | . Bandwidth
. . . | | . Available . . . | | . Available
Engi- . . . | | . for non-priority use Engi- . . . | | . for non-priority use
neered .or.or. |xxxxxxxxxxxxxx| . neered .or.or. |xxxxxxxxxxxxxx| .
. . . |xxxxxxxxxxxxxx| . . . . |xxxxxxxxxxxxxx| .
Capacity. . . |xxxxxxxxxxxxxx| . Capacity. . . |xxxxxxxxxxxxxx| .
v . . |xxxxxxxxxxxxxx| v v . . |xxxxxxxxxxxxxx| v
. . |--------------| --- . . |--------------| ---
v . | | ^ v . | | ^
. | | . Bandwidth available for . | | . Bandwidth available for
v | | v priority use v | | v priority use
------------------------- -------------------------
Figure 5: Partial load of non-priority calls Figure 6: Partial load of non-priority calls
Figure 6 shows the same amount of non-priority load being used at Figure 7 shows the same amount of non-priority load being used at
this link, and a small amount of priority bandwidth being used. this link, and a small amount of priority bandwidth being used.
----------------------- -----------------------
^ ^ ^ | | ^ ^ ^ ^ | | ^
. . . | | . . . . | | .
Total . . . | | . Bandwidth Total . . . | | . Bandwidth
. . . | | . Available . . . | | . Available
Engi- . . . | | . for non-priority use Engi- . . . | | . for non-priority use
neered .or.or. |xxxxxxxxxxxxxx| . neered .or.or. |xxxxxxxxxxxxxx| .
. . . |xxxxxxxxxxxxxx| . . . . |xxxxxxxxxxxxxx| .
Capacity. . . |xxxxxxxxxxxxxx| . Capacity. . . |xxxxxxxxxxxxxx| .
v . . |xxxxxxxxxxxxxx| v v . . |xxxxxxxxxxxxxx| v
. . |--------------| --- . . |--------------| ---
v . | | ^ v . | | ^
. | | . Bandwidth available for . | | . Bandwidth available for
v |oooooooooooooo| v priority use v |oooooooooooooo| v priority use
------------------------- -------------------------
Figure 6: Partial load of non-priority calls & partial load of Figure 7: Partial load of non-priority calls & partial load of
priority calls Calls priority calls Calls
Figure 7 shows the case where non-priority load equates or exceeds Figure 8 shows the case where non-priority load equates or exceeds
the maximum bandwidth available to non-priority traffic. Note that the maximum bandwidth available to non-priority traffic. Note that
additional non-priority sessions would be rejected even if the additional non-priority sessions would be rejected even if the
bandwidth reserved for priority sessions is not fully utilized. bandwidth reserved for priority sessions is not fully utilized.
----------------------- -----------------------
^ ^ ^ |xxxxxxxxxxxxxx| ^ ^ ^ ^ |xxxxxxxxxxxxxx| ^
. . . |xxxxxxxxxxxxxx| . . . . |xxxxxxxxxxxxxx| .
Total . . . |xxxxxxxxxxxxxx| . Bandwidth Total . . . |xxxxxxxxxxxxxx| . Bandwidth
. . . |xxxxxxxxxxxxxx| . Available . . . |xxxxxxxxxxxxxx| . Available
Engi- . . . |xxxxxxxxxxxxxx| . for non-priority use Engi- . . . |xxxxxxxxxxxxxx| . for non-priority use
neered .or.or. |xxxxxxxxxxxxxx| . neered .or.or. |xxxxxxxxxxxxxx| .
. . . |xxxxxxxxxxxxxx| . . . . |xxxxxxxxxxxxxx| .
Capacity. . . |xxxxxxxxxxxxxx| . Capacity. . . |xxxxxxxxxxxxxx| .
v . . |xxxxxxxxxxxxxx| v v . . |xxxxxxxxxxxxxx| v
. . |--------------| --- . . |--------------| ---
v . | | ^ v . | | ^
. | | . Bandwidth available for . | | . Bandwidth available for
v |oooooooooooooo| v priority use v |oooooooooooooo| v priority use
------------------------- -------------------------
Figure 7: Full non-priority load & partial load of priority calls Figure 8: Full non-priority load & partial load of priority calls
Figure 8 shows the case where the priority traffic equates or exceeds Figure 9 shows the case where the priority traffic equates or exceeds
the bandwidth reserved for such priority traffic. the bandwidth reserved for such priority traffic.
In that case additional priority sessions could not be accepted. In that case additional priority sessions could not be accepted.
Note that this does not mean that such sessions are dropped Note that this does not mean that such sessions are dropped
altogether: they may be handled by mechanisms, which are beyond the altogether: they may be handled by mechanisms, which are beyond the
scope of this particular document (such as establishment through scope of this particular document (such as establishment through
preemption of existing non-priority sessions, or such as queuing of preemption of existing non-priority sessions, or such as queuing of
new priority session requests until capacity becomes available again new priority session requests until capacity becomes available again
for priority traffic). for priority traffic).
skipping to change at page 26, line 21 skipping to change at page 28, line 21
neered .or.or. |xxxxxxxxxxxxxx| . neered .or.or. |xxxxxxxxxxxxxx| .
. . . |xxxxxxxxxxxxxx| . . . . |xxxxxxxxxxxxxx| .
Capacity. . . | | . Capacity. . . | | .
v . . | | v v . . | | v
. . |--------------| --- . . |--------------| ---
v . |oooooooooooooo| ^ v . |oooooooooooooo| ^
. |oooooooooooooo| . Bandwidth available for . |oooooooooooooo| . Bandwidth available for
v |oooooooooooooo| v priority use v |oooooooooooooo| v priority use
------------------------- -------------------------
Figure 8: Partial non-priority load & Full priority load Figure 9: Partial non-priority load & Full priority load
A.2. Admission Priority with Russian Dolls Model (RDM) A.2. Admission Priority with Russian Dolls Model (RDM)
This section illustrates operations of admission priority when a This section illustrates operations of admission priority when a
Russian Dolls Model (RDM) is used for bandwidth allocation across Russian Dolls Model (RDM) is used for bandwidth allocation across
non-priority traffic and priority traffic. A property of the Russian non-priority traffic and priority traffic. A property of the Russian
Dolls Model is that priority traffic can use the bandwidth which is Dolls Model is that priority traffic can use the bandwidth which is
not currently used by non-priority traffic. not currently used by non-priority traffic.
As with the MAM model, an operator may map the RDM model onto the As with the MAM model, an operator may map the RDM model onto the
skipping to change at page 26, line 51 skipping to change at page 28, line 51
available to non-priority and priority traffic to the engineered available to non-priority and priority traffic to the engineered
capacity limits; As an example, if the engineered capacity limit on a capacity limits; As an example, if the engineered capacity limit on a
given link is X, the operator may configure the bandwidth available given link is X, the operator may configure the bandwidth available
to non-priority traffic to 95% of X, and the bandwidth available to to non-priority traffic to 95% of X, and the bandwidth available to
non-priority and priority traffic to X. non-priority and priority traffic to X.
Finally, the operator may decide to strike a balance in between. The Finally, the operator may decide to strike a balance in between. The
considerations presented for these policies in the previous section considerations presented for these policies in the previous section
in the MAM context are equally applicable to RDM. in the MAM context are equally applicable to RDM.
Figure 9 shows the case where only some of the bandwidth available to Figure 10 shows the case where only some of the bandwidth available
non-priority traffic is being used and a small amount of priority to non-priority traffic is being used and a small amount of priority
traffic is in place. In that situation both new non-priority traffic is in place. In that situation both new non-priority
sessions and new priority sessions would be accepted. sessions and new priority sessions would be accepted.
-------------------------------------- --------------------------------------
|xxxxxxxxxxxxxx| . ^ |xxxxxxxxxxxxxx| . ^
|xxxxxxxxxxxxxx| . Bandwidth . |xxxxxxxxxxxxxx| . Bandwidth .
|xxxxxxxxxxxxxx| . Available for . |xxxxxxxxxxxxxx| . Available for .
|xxxxxxxxxxxxxx| . non-priority . |xxxxxxxxxxxxxx| . non-priority .
|xxxxxxxxxxxxxx| . use . |xxxxxxxxxxxxxx| . use .
|xxxxxxxxxxxxxx| . . Bandwidth |xxxxxxxxxxxxxx| . . Bandwidth
| | . . available for | | . . available for
| | v . non-priority | | v . non-priority
|--------------| --- . and priority |--------------| --- . and priority
| | . use | | . use
| | . | | .
|oooooooooooooo| v |oooooooooooooo| v
--------------------------------------- ---------------------------------------
Figure 9: Partial non-priority load & Partial Aggregate load Figure 10: Partial non-priority load & Partial Aggregate load
Figure 10 shows the case where all of the bandwidth available to non- Figure 11 shows the case where all of the bandwidth available to non-
priority traffic is being used and a small amount of priority traffic priority traffic is being used and a small amount of priority traffic
is in place. In that situation new priority sessions would be is in place. In that situation new priority sessions would be
accepted but new non-priority sessions would be rejected. accepted but new non-priority sessions would be rejected.
-------------------------------------- --------------------------------------
|xxxxxxxxxxxxxx| . ^ |xxxxxxxxxxxxxx| . ^
|xxxxxxxxxxxxxx| . Bandwidth . |xxxxxxxxxxxxxx| . Bandwidth .
|xxxxxxxxxxxxxx| . Available for . |xxxxxxxxxxxxxx| . Available for .
|xxxxxxxxxxxxxx| . non-priority . |xxxxxxxxxxxxxx| . non-priority .
|xxxxxxxxxxxxxx| . use . |xxxxxxxxxxxxxx| . use .
|xxxxxxxxxxxxxx| . . Bandwidth |xxxxxxxxxxxxxx| . . Bandwidth
|xxxxxxxxxxxxxx| . . available for |xxxxxxxxxxxxxx| . . available for
|xxxxxxxxxxxxxx| v . non-priority |xxxxxxxxxxxxxx| v . non-priority
|--------------| --- . and priority |--------------| --- . and priority
| | . use | | . use
| | . | | .
|oooooooooooooo| v |oooooooooooooo| v
--------------------------------------- ---------------------------------------
Figure 10: Full non-priority load & Partial Aggregate load Figure 11: Full non-priority load & Partial Aggregate load
Figure 11 shows the case where only some of the bandwidth available Figure 12 shows the case where only some of the bandwidth available
to non-priority traffic is being used and a heavy load of priority to non-priority traffic is being used and a heavy load of priority
traffic is in place. In that situation both new non-priority traffic is in place. In that situation both new non-priority
sessions and new priority sessions would be accepted. Note that, as sessions and new priority sessions would be accepted. Note that, as
illustrated in Figure 10, priority sessions use some of the bandwidth illustrated in Figure 11, priority sessions use some of the bandwidth
currently not used by non-priority traffic. currently not used by non-priority traffic.
-------------------------------------- --------------------------------------
|xxxxxxxxxxxxxx| . ^ |xxxxxxxxxxxxxx| . ^
|xxxxxxxxxxxxxx| . Bandwidth . |xxxxxxxxxxxxxx| . Bandwidth .
|xxxxxxxxxxxxxx| . Available for . |xxxxxxxxxxxxxx| . Available for .
|xxxxxxxxxxxxxx| . non-priority . |xxxxxxxxxxxxxx| . non-priority .
|xxxxxxxxxxxxxx| . use . |xxxxxxxxxxxxxx| . use .
| | . . Bandwidth | | . . Bandwidth
| | . . available for | | . . available for
|oooooooooooooo| v . non-priority |oooooooooooooo| v . non-priority
|--------------| --- . and priority |--------------| --- . and priority
|oooooooooooooo| . use |oooooooooooooo| . use
|oooooooooooooo| . |oooooooooooooo| .
|oooooooooooooo| v |oooooooooooooo| v
--------------------------------------- ---------------------------------------
Figure 11: Partial non-priority load & Heavy Aggregate load Figure 12: Partial non-priority load & Heavy Aggregate load
Figure 12 shows the case where all of the bandwidth available to non- Figure 13 shows the case where all of the bandwidth available to non-
priority traffic is being used and all of the remaining available priority traffic is being used and all of the remaining available
bandwidth is used by priority traffic. In that situation new non- bandwidth is used by priority traffic. In that situation new non-
priority sessions would be rejected. In that situation new priority priority sessions would be rejected. In that situation new priority
sessions could not be accepted right away. Those priority sessions sessions could not be accepted right away. Those priority sessions
may be handled by mechanisms, which are beyond the scope of this may be handled by mechanisms, which are beyond the scope of this
particular document (such as established through preemption of particular document (such as established through preemption of
existing non-priority sessions, or such as queuing of new priority existing non-priority sessions, or such as queuing of new priority
session requests until capacity becomes available again for priority session requests until capacity becomes available again for priority
traffic). traffic).
skipping to change at page 29, line 20 skipping to change at page 31, line 20
|xxxxxxxxxxxxxx| . use . |xxxxxxxxxxxxxx| . use .
|xxxxxxxxxxxxxx| . . Bandwidth |xxxxxxxxxxxxxx| . . Bandwidth
|xxxxxxxxxxxxxx| . . available for |xxxxxxxxxxxxxx| . . available for
|xxxxxxxxxxxxxx| v . non-priority |xxxxxxxxxxxxxx| v . non-priority
|--------------| --- . and priority |--------------| --- . and priority
|oooooooooooooo| . use |oooooooooooooo| . use
|oooooooooooooo| . |oooooooooooooo| .
|oooooooooooooo| v |oooooooooooooo| v
--------------------------------------- ---------------------------------------
Figure 12: Full non-priority load & Full Aggregate load Figure 13: Full non-priority load & Full Aggregate load
A.3. Admission Priority with Priority Bypass Model (PrBM) A.3. Admission Priority with Priority Bypass Model (PrBM)
This section illustrates operations of admission priority when a This section illustrates operations of admission priority when a
simple Priority Bypass Model (PrBM) is used for bandwidth allocation simple Priority Bypass Model (PrBM) is used for bandwidth allocation
across non-priority traffic and priority traffic. With the Priority across non-priority traffic and priority traffic. With the Priority
Bypass Model, non-priority traffic is subject to resource based Bypass Model, non-priority traffic is subject to resource based
admission control while priority traffic simply bypasses the resource admission control while priority traffic simply bypasses the resource
based admission control. In other words: based admission control. In other words:
skipping to change at page 30, line 25 skipping to change at page 32, line 25
decide to configure the bandwidth limit for non-priority traffic to decide to configure the bandwidth limit for non-priority traffic to
below the engineered capacity limits (so that the sum of the non- below the engineered capacity limits (so that the sum of the non-
priority and priority traffic stays below the engineered capacity); priority and priority traffic stays below the engineered capacity);
As an example, if the engineered capacity limit on a given link is X, As an example, if the engineered capacity limit on a given link is X,
the operator may configure the bandwidth limit for non-priority the operator may configure the bandwidth limit for non-priority
traffic to 95% of X. Finally, the operator may decide to strike a traffic to 95% of X. Finally, the operator may decide to strike a
balance in between. The considerations presented for these policies balance in between. The considerations presented for these policies
in the previous sections in the MAM and RDM contexts are equally in the previous sections in the MAM and RDM contexts are equally
applicable to the Priority Bypass Model. applicable to the Priority Bypass Model.
Figure 13 illustrates the bandwidth allocation with the Priority Figure 14 illustrates the bandwidth allocation with the Priority
Bypass Model. Bypass Model.
----------------------- -----------------------
^ ^ | | ^ ^ ^ | | ^
. . | | . . . | | .
Total . . | | . Bandwidth Limit Total . . | | . Bandwidth Limit
(1) (2) | | . (on non-priority + priority) (1) (2) | | . (on non-priority + priority)
Engi- . . | | . for admission Engi- . . | | . for admission
neered . or . | | . of non-priority traffic neered . or . | | . of non-priority traffic
. . | | . . . | | .
Capacity. . | | . Capacity. . | | .
v . | | v v . | | v
. |--------------| --- . |--------------| ---
. | | . | |
v | | v | |
| | | |
Figure 13: Priority Bypass Model Bandwidth Allocation Figure 14: Priority Bypass Model Bandwidth Allocation
Figure 14 shows some of the non-priority capacity of this link being Figure 15 shows some of the non-priority capacity of this link being
used. In this situation, both new non-priority and new priority used. In this situation, both new non-priority and new priority
sessions would be accepted. sessions would be accepted.
----------------------- -----------------------
^ ^ |xxxxxxxxxxxxxx| ^ ^ ^ |xxxxxxxxxxxxxx| ^
. . |xxxxxxxxxxxxxx| . . . |xxxxxxxxxxxxxx| .
Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit
(1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority) (1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority)
Engi- . . | | . for admission Engi- . . | | . for admission
neered . or . | | . of non-priority traffic neered . or . | | . of non-priority traffic
. . | | . . . | | .
Capacity. . | | . Capacity. . | | .
v . | | v v . | | v
. |--------------| --- . |--------------| ---
. | | . | |
v | | v | |
| | | |
Figure 14: Partial load of non-priority calls Figure 15: Partial load of non-priority calls
Figure 15 shows the same amount of non-priority load being used at Figure 16 shows the same amount of non-priority load being used at
this link, and a small amount of priority bandwidth being used. In this link, and a small amount of priority bandwidth being used. In
this situation, both new non-priority and new priority sessions would this situation, both new non-priority and new priority sessions would
be accepted. be accepted.
----------------------- -----------------------
^ ^ |xxxxxxxxxxxxxx| ^ ^ ^ |xxxxxxxxxxxxxx| ^
. . |xxxxxxxxxxxxxx| . . . |xxxxxxxxxxxxxx| .
Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit
(1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority) (1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority)
Engi- . . |oooooooooooooo| . for admission Engi- . . |oooooooooooooo| . for admission
neered . or . | | . of non-priority traffic neered . or . | | . of non-priority traffic
. . | | . . . | | .
Capacity. . | | . Capacity. . | | .
v . | | v v . | | v
. |--------------| --- . |--------------| ---
. | | . | |
v | | v | |
| | | |
Figure 15: Partial load of non-priority calls & partial load of Figure 16: Partial load of non-priority calls & partial load of
priority calls priority calls
Figure 16 shows the case where aggregate non-priority and priority Figure 17 shows the case where aggregate non-priority and priority
load exceeds the bandwidth limit for admission of non-priority load exceeds the bandwidth limit for admission of non-priority
traffic. In this situation, any new non-priority session is rejected traffic. In this situation, any new non-priority session is rejected
while any new priority session is admitted. while any new priority session is admitted.
----------------------- -----------------------
^ ^ |xxxxxxxxxxxxxx| ^ ^ ^ |xxxxxxxxxxxxxx| ^
. . |xxxxxxxxxxxxxx| . . . |xxxxxxxxxxxxxx| .
Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit Total . . |xxxxxxxxxxxxxx| . Bandwidth Limit
(1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority) (1) (2) |xxxxxxxxxxxxxx| . (on non-priority + priority)
Engi- . . |oooooooooooooo| . for admission Engi- . . |oooooooooooooo| . for admission
neered . or . |xxxooxxxooxxxo| . of non-priority traffic neered . or . |xxxooxxxooxxxo| . of non-priority traffic
. . |xxoxxxxxxoxxxx| . . . |xxoxxxxxxoxxxx| .
Capacity. . |oxxxooooxxxxoo| . Capacity. . |oxxxooooxxxxoo| .
v . |xxoxxxooxxxxxx| v v . |xxoxxxooxxxxxx| v
. |--------------| --- . |--------------| ---
. |oooooooooooooo| . |oooooooooooooo|
v | | v | |
| | | |
Figure 16: Full non-priority load Figure 17: Full non-priority load
Appendix B. Example Usages of RSVP Extensions Appendix B. Example Usages of RSVP Extensions
This section provides examples of how RSVP extensions defined in this This section provides examples of how RSVP extensions defined in this
document can be used (in conjunctions with other RSVP functionality document can be used (in conjunctions with other RSVP functionality
and SIP functionality) to enforce different hypothetical policies for and SIP functionality) to enforce different hypothetical policies for
handling Emergency sessions in a given administrative domain. This handling Emergency sessions in a given administrative domain. This
Appendix does not provide additional specification. It is only Appendix does not provide additional specification. It is only
included in this document for illustration purposes. included in this document for illustration purposes.
skipping to change at page 34, line 18 skipping to change at page 36, line 18
o using Preemption Policy Element in RSVP with: o using Preemption Policy Element in RSVP with:
* setup (Emergency) > defending (Non-Emergency) * setup (Emergency) > defending (Non-Emergency)
* setup (Non-Emergency) <= defending (Emergency) * setup (Non-Emergency) <= defending (Emergency)
If one wants to implement an emergency service based on Call If one wants to implement an emergency service based on Call
Queueing, on "prioritized access to network layer resources", and Queueing, on "prioritized access to network layer resources", and
ensure that "emergency" sessions can partially preempt regular ensure that "emergency" sessions can partially preempt regular
sessions (ie reduce their reservation size), one could do that by sessions (i.e. reduce their reservation size), one could do that by
signaling emergency sessions: signaling emergency sessions:
o using "Resource-Priority" Header in SIP o using "Resource-Priority" Header in SIP
o using Admission-Priority Policy Element in RSVP o using Admission-Priority Policy Element in RSVP
o using Preemption in Policy Element RSVP with: o using Preemption in Policy Element RSVP with:
* setup (Emergency) > defending (Non-Emergency) * setup (Emergency) > defending (Non-Emergency)
skipping to change at page 36, line 4 skipping to change at line 1618
Phone: +1 972 813 5208 Phone: +1 972 813 5208
Email: jmpolk@cisco.com Email: jmpolk@cisco.com
Ken Carlberg Ken Carlberg
G11 G11
123a Versailles Circle 123a Versailles Circle
Towson, MD 21204 Towson, MD 21204
United States United States
Email: carlberg@g11.org.uk Email: carlberg@g11.org.uk
Full Copyright Statement
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