Diameter Maintenance and K. Carlberg, Ed.
Extensions (DIME) G11
Internet-Draft T. Taylor
Intended status: Standards Track Huawei Technologies
October, 2010
Diameter Priority Attribute Value Pairs
draft-ietf-dime-priority-avps-03.txt
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Abstract
This document defines Attribute-Value Pair (AVP) containers for various
priority parameters for use with Diameter and the AAA framework. The
parameters themselves are defined in several different protocols that
operate at either the network or application layer.
1. Introduction
This document defines a number of Attribute-Value Pairs (AVP) that can
be used within the Diameter protocol [RFC3588] to convey a specific set
of priority parameters. These parameters are specified in other
documents, but are briefly described below. The corresponding AVPs
defined in Section 3 are an extension to those defined in [RFC5866].
Priority influences the distribution of resources. This influence may
be probabilistic, ranging between (but not including) 0% and 100%, or it
may be in the form of a guarantee to either receive or not receive the
resource.
The influence attributed to prioritization may also affect QoS, but it
is not to be confused with QoS. As an example, if packets of two or more
flows are contending for the same shared resources, prioritization helps
determine which packet receives the resource. However, this allocation
of resource does not correlate directly to any specific delay or loss
bounds that have been associated with the packet.
Another example of how prioritization can be realized is articulated in
Appendix A.3 (the priority by-pass model) of
[I-D.ietf-tsvwg-emergency-rsvp]. In this case, prioritized flows may
gain access to resources that are never shared with non-prioritized
flows.
1.1 Other Priority-Related AVPs
3rd Generation Partnership Project (3GPP) has defined several Diameter
AVPs that support prioritization of sessions. The following AVPs are
intended to be used for priority services (e.g., Multimedia Priority
Service):
- Reservation-Priority AVP as defined in [ETSI]
- AF-Application-Identifier AVP as defined in [3GPPa]
- Priority-Level AVP (as part of the Allocation Retention Priority AVP)
as defined in [3GPPb]
- Session-Priority AVP as defined in [3GPPc][3GPPd]
Both the Reservation-Priority AVP and the Priority-Level AVP can carry a
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priority level associated with a session initiated by a user. We note
that these AVPs are defined from the allotment set aside for 3GPP for
Diameter-based interfaces. 3GPP has also defined other priority
information for use on non-Diameter based interfaces. However, this
work is not relevant to the present document. The AVPs defined by 3GPP
are to be viewed as private implementations operating within a walled
garden.
2. Terminology and Abbreviations
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 [RFC2119].
3. Priority Parameter Encoding
This section defines a set of priority AVPs. This set is for use with
the DIAMETER QoS application [RFC5866] and represents a continuation of
the list of AVPs defined in [RFC5624]. The syntax notation used is that
of [RFC3588].
3.1. Dual-Priority AVP
The Dual-Priority AVP is a grouped AVP consisting of two AVPs; the
Preemption-Priority and the Defending-Priority AVP. These AVPs are
derived from the corresponding priority fields specified in the Signaled
Preemption Priority Policy Element [RFC3181] of RSVP [RFC2205]. The
Defending-Priority is set when the reservation has been admitted. The
Preemption-Priority of a newly requested reservation is compared with
the Defending Priority of a previously admitted flow. The actions taken
based upon the result of this comparison are a function of local policy.
Dual-Priority ::= < AVP Header: TBD >
{ Preemption-Priority }
{ Defending-Priority }
3.1.1. Preemption-Priority AVP
The Preemption-Priority AVP (AVP Code TBD) is of type Unsigned32.
Higher values represent higher priority. The value encoded in this AVP
is the same as the preemption priority value that would be encoded in
the signaled preemption priority policy element.
3.1.2. Defending-Priority AVP
The Defending-Priority AVP (AVP Code TBD) is of type Unsigned32. Higher
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values represent higher priority. The value encoded in this AVP is the
same as the defending priority value that would be encoded in the
signaled preemption priority policy element.
3.2. Admission-Priority AVP
The Admission-Priority AVP (AVP Code TBD) is of type Unsigned32. The
admission priority of the flow is used to increase the probability of
session establishment for selected flows. Higher values represent
higher priority. A given admission priority is encoded in this
information element using the same value as when encoded in the
admission priority parameter defined in Section 5.1 of
[I-D.ietf-tsvwg-emergency-rsvp].
3.3. SIP-Resource-Priority AVP
The SIP-Resource-Priority AVP is a grouped AVP consisting of two AVPs,
the SIP-Resource-Priority-Namespace and the SIP-Resource- Priority-Value
AVP, which are derived from the corresponding optional header fields in
[rfc4412].
SIP-Resource-Priority ::= < AVP Header: TBD >
{ SIP-Resource-Priority-Namespace }
{ SIP-Resource-Priority-Value }
3.3.1. SIP-Namespace AVP
The SIP-Resource-Priority-Namespace AVP (AVP Code TBD) is of type
UTF8String. This AVP contains a string that identifies a unique ordered
set of priority values as described in [rfc4412].
3.3.2 SIP-Resource-Priority-Value AVP
The SIP-Resource-Priority-Value AVP (AVP Code TBD) is of type
UTF8String. This AVP contains a string that identifies a specific
priority value within the set identified by the
SIP-Resource-Priority-Namespace AVP, as described in [rfc4412].
3.4. Application-Level-Resource-Priority AVP
The Application-Level-Resource-Priority (ALRP) AVP is a grouped AVP
consisting of two AVPs, the ALRP-Namespace AVP and the ALRP-Value AVP.
Application-Level-Resource-Priority ::= < AVP Header: TBD >
{ ALRP-Namespace }
{ ALRP-Value }
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A description of the semantics of the parameter values can be found in
[RFC4412] and in [I-D.ietf-tsvwg-emergency-rsvp]. The registry set up
by [RFC4412] provided string values for both the priority namespace and
the priority values associated with that namespace.
[I-D.ietf-tsvwg-emergency-rsvp] modifies that registry to assign
numerical values to both the namespace identifiers and the priority
values within them. Consequently, SIP-Resource-Priority and
Application-Level-Resource-Priority AVPs convey the same priority
semantics, but with differing syntax. In the former case, an
alpha-numeric encoding is used, while the latter case is constrained to
a numeric-only value.
3.4.1. ALRP-Namespace AVP
The ALRP-Namespace AVP (AVP Code TBD) is of type Unsigned32. This AVP
contains a numerical value identifying the namespace of the
application-level resource priority as described in
[I-D.ietf-tsvwg-emergency-rsvp].
3.4.2. ALRP-Value AVP
The ALRP-Priority AVP (AVP Code TBD) is of type Unsigned32. This AVP
contains the priority value within the ALRP-Namespace, as described in
[I-D.ietf-tsvwg-emergency-rsvp].
4. IANA Considerations
4.1. AVP Codes
IANA is requested to allocate AVP codes for the following AVPs that are
defined in this document.
+------------------------------------------------------------------+
| AVP Section |
|AVP Name Code Defined Data Type |
+------------------------------------------------------------------+
|Dual-Priority TBD 3.1 Grouped |
|Preemption-Priority TBD 3.1.1 Unsigned32 |
|Defending-Priority TBD 3.1.2 Unsigned32 |
|Admission-Priority TBD 3.2 Unsigned32 |
|SIP-Resource-Priority TBD 3.3 Grouped |
|SIP-Namespace TBD 3.3.1 UTF8String |
|SIP-Value TBD 3.3.2 UTF8String |
|Application-Level-Resource-Priority TBD 3.4 Grouped |
|ALRP-Namespace TBD 3.4.1 Unsigned32 |
|ALRP-Value TBD 3.4.2 Unsigned32 |
+------------------------------------------------------------------+
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4.2. QoS Profile
IANA is requested to allocate a new value from the Authentication,
Authorization, and Accounting (AAA) Parameters/QoS Profile registry
defined in [RFC5624] for the QoS profile defined in this document. The
name of the profile is "Resource priority parameters".
5. Security Considerations
This document describes the extension of Diameter for conveying Quality
of Service information. The security considerations of the Diameter
protocol itself have been discussed in RFC 3588 [RFC3588]. Use of the
AVPs defined in this document MUST take into consideration the security
issues and requirements of the Diameter base protocol.
6. Acknowledgements
We would like to thank Lionel Morand, Janet Gunn, Piers O'Hanlon for the
comments on the draft, and Lars Eggert, Jan Engelhardt, Francois
LeFaucheur, John Loughney, An Nguyen, Dave Oran, James Polk, Martin
Stiemerling, and Magnus Westerlund for their help with resolving
problems regarding the Admission Priority and the ALRP parameter.
7. References
7.1. Normative References
[I-D.ietf-tsvwg-emergency-rsvp]
Faucheur, F., Polk, J., and K. Carlberg, "Resource
ReSerVation Protocol (RSVP) Extensions for Emergency
Services", draft-ietf-tsvwg-emergency-rsvp-14 (work in
progress), Nov 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, B., et. al., "Resource ReSerVation Protocol (RSVP)
-- Version 1 Functional Specification", RFC 2205, September
1997
[RFC3181] Herzog, S., "Signaled Preemption Priority Policy Element",
RFC 3181, October 2001.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
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Priority for the Session Initiation Protocol (SIP)",
RFC 4412, February 2006.
[RFC5624] Korhonen, J., Tschofenig, H., and E. Davies, "Quality of
Service Parameters for Usage with Diameter", RFC 5624,
Aug 2009.
[RFC5866] Sun, D., et. al., "Diameter Quality-of-Service
Application", RFC 5866, May 2010.
7.2. Informative References
[3GPPa] "TS 29.214: Policy and charging control over Rx reference
point", 3GPP, October, 2010
[3GPPb] "TS 29.212: Policy and charging control over Gx reference
point", 3GPP, October, 2010
[3GPPc] "TS 29.229: Cx and Dx interfaces based on the Diameter
protocol; Protocol details", 3GPP, September, 2010
[3GPPd] "TS 29.329: Sh interface based on the Diameter protocol;
Protocol details", 3GPP, September, 2010
[ETSI] "TS 183 017: Telecommunications and Internet Converged
Services and Protocols for Advanced Networking (TISPAN);
Resource and Admission Control", ETSI
Authors' Addresses
Ken Carlberg (editor) Tom Taylor
G11 Huawei Technologies
1601 Clarendon Dr 1852 Lorraine Ave
Arlington, VA 22209 Ottawa
United States Canada
Email: carlberg@g11.org.uk Email: tom111.taylor@bell.net
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