Diameter Maintenance and J. Korhonen, Ed.
Extensions (DIME) H. Tschofenig
Internet-Draft Nokia Siemens Networks
Intended status: Standards Track December 18, 2008
Expires: June 21, 2009
Quality of Service Parameters for Usage with Diameter
draft-ietf-dime-qos-parameters-08.txt
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Abstract
This document defines a number of Quality of Service (QoS) parameters
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that can be reused for conveying QoS information within Diameter.
The payloads used to carry these QoS parameters are opaque for the
AAA client and the AAA server itself and interpreted by the
respective Resource Management Function.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Abbreviations . . . . . . . . . . . . . . . . 4
3. QoS Parameter Encoding . . . . . . . . . . . . . . . . . . . . 4
3.1. TMOD-1 AVP . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. TMOD-Rate AVP . . . . . . . . . . . . . . . . . . . . 4
3.1.2. TMOD-Size AVP . . . . . . . . . . . . . . . . . . . . 4
3.1.3. Peak-Data-Rate AVP . . . . . . . . . . . . . . . . . . 4
3.1.4. Minimum-Policed-Unit AVP . . . . . . . . . . . . . . . 4
3.2. TMOD-2 AVP . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Priority AVP . . . . . . . . . . . . . . . . . . . . . . . 5
3.3.1. Preemption-Priority AVP . . . . . . . . . . . . . . . 5
3.3.2. Defending-Priority AVP . . . . . . . . . . . . . . . . 5
3.4. Admission-Priority AVP . . . . . . . . . . . . . . . . . . 5
3.5. ALRP AVP . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.5.1. ALRP-Namespace AVP . . . . . . . . . . . . . . . . . . 6
3.5.2. ALRP-Priority AVP . . . . . . . . . . . . . . . . . . 6
3.6. PHB-Class AVP . . . . . . . . . . . . . . . . . . . . . . 6
3.6.1. Case 1: Single PHB . . . . . . . . . . . . . . . . . . 6
3.6.2. Case 2: Set of PHBs . . . . . . . . . . . . . . . . . 7
3.6.3. Case 3: Experimental or Local Use PHBs . . . . . . . . 7
3.7. DSTE-Class-Type AVP . . . . . . . . . . . . . . . . . . . 7
4. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
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1. Introduction
This document defines a number of Quality of Service (QoS) parameters
that can be reused for conveying QoS information within the Diameter
protocol.
This document defines an initial QoS profile containing a set of QoS
AVPs.
The traffic model (TMOD) AVPs are containers consisting of four AVPs
and is a way to describe the traffic source.
o rate (r)
o bucket size (b)
o peak rate (p)
o minimum policed unit (m)
The encoding of <TMOD-1> and <TMOD-2> can be found in Section 3.1 and
Section 3.2 and the semantic is described in [RFC2210] and in
[RFC2215]. <TMOD-2> is, for example, needed by some DiffServ
applications. I t is typically assumed that DiffServ EF traffic is
shaped at the ingress by a single rate token bucket. Therefore, a
single TMOD parameter is sufficient to signal DiffServ EF traffic.
However, for DiffServ AF traffic two sets of token bucket parameters
are needed, one token bucket for the average traffic and one token
bucket for the burst traffic. [RFC2697] defines a Single Rate Three
Color Marker (srTCM), which meters a traffic stream and marks its
packets according to three traffic parameters, Committed Information
Rate (CIR), Committed Burst Size (CBS), and Excess Burst Size (EBS),
to be either green, yellow, or red. A packet is marked green if it
does not exceed the CBS, yellow if it does exceed the CBS, but not
the EBS, and red otherwise. [RFC2697] defines specific procedures
using two token buckets that run at the same rate. Therefore, two
TMOD AVPs are sufficient to distinguish among three levels of drop
precedence. An example is also described in the appendix of
[RFC2597].
The <Preemption-Priority> AVP refers to the priority of a new flow
compared with the <Defending-Priority> AVP of previously admitted
flows. Once a flow is admitted, the preemption priority becomes
irrelevant. The <Defending-Priority> AVP is used to compare with the
preemption priority of new flows. For any specific flow, its
preemption priority is always less than or equal to the defending
priority.
The <Admission-Priority> AVP and <ALRP> AVP provide an essential way
to differentiate flows for emergency services, ETS, E911, etc., and
assign them a higher admission priority than normal priority flows
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and best-effort priority flows.
Resource reservations might refer to a packet processing with a
particular DiffServ per-hop behavior (PHB) [RFC2475] (using the <PHB-
Class> AVP) or to a particular QoS class, e.g., a DiffServ-aware MPLS
traffic engineering (DSTE) class type, as described in [RFC3564] and
in [RFC4124], using the <DSTE-Class-Type> AVP.
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. QoS Parameter Encoding
3.1. TMOD-1 AVP
The TMOD-1 AVP is obtained from [RFC2210] and [RFC2215]. The
structure of the AVP is as follows:
TMOD-1 ::= < AVP Header: TBD >
{ TMOD-Rate }
{ TMOD-Size }
{ Peak-Data-Rate }
{ Minimum-Policed-Unit }
3.1.1. TMOD-Rate AVP
The TMOD-Rate AVP (AVP Code TBD) is of type Float32 and contains the
rate (r).
3.1.2. TMOD-Size AVP
The TMOD-Size AVP (AVP Code TBD) is of type Float32 and contains the
bucket size (b).
3.1.3. Peak-Data-Rate AVP
The Peak-Data-Rate AVP (AVP Code TBD) is of type Float32 and contains
the peak rate (p).
3.1.4. Minimum-Policed-Unit AVP
The Minimum-Policed-Unit AVP (AVP Code TBD) is of type Unsigned32 and
contains the minimum policed unit (m).
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3.2. TMOD-2 AVP
A description of the semantic of the parameter values can be found in
[RFC2215]. The TMOD-2 AVP is useful in a DiffServ environment. The
coding for the TMOD-2 AVP is as follows:
TMOD-2 ::= < AVP Header: TBD >
{ TMOD-Rate }
{ TMOD-Size }
{ Peak-Data-Rate }
{ Minimum-Policed-Unit }
3.3. Priority AVP
The Priority AVP is a grouped AVP consisting of two AVPs, the
Preemption-Priority and the Defending-Priority AVP. A description of
the semantic can be found in [RFC3181].
Priority ::= < AVP Header: TBD >
{ Preemption-Priority }
{ Defending-Priority }
3.3.1. Preemption-Priority AVP
The Preemption-Priority AVP (AVP Code TBD) is of type Unsigned32 and
it indicates the priority of the new flow compared with the defending
priority of previously admitted flows. Higher values represent
higher priority.
3.3.2. Defending-Priority AVP
The Defending-Priority AVP (AVP Code TBD) is of type Unsigned32.
Once a flow is admitted, the preemption priority becomes irrelevant.
Instead, its defending priority is used to compare with the
preemption priority of new flows.
3.4. Admission-Priority AVP
The Admission-Priority AVP (AVP Code TBD) is of type Unsigned32.
The admission control priority of the flow, in terms of access to
network bandwidth in order to provide higher probability of call
completion to 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 AVP defined in Section 3.1 of
[I-D.ietf-tsvwg-emergency-rsvp] (Admission Priority parameter).
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3.5. ALRP AVP
The Application-Level Resource Priority (ALRP) AVP is a grouped AVP
consisting of two AVPs, the ALRP-Namespace and the ALRP-Priority AVP.
A description of the semantic of the parameter values can be found in
[RFC4412] and in [I-D.ietf-tsvwg-emergency-rsvp]. The coding for
parameter is as follows:
ALRP ::= < AVP Header: TBD >
{ ALRP-Namespace }
{ ALRP-Priority }
3.5.1. ALRP-Namespace AVP
The ALRP-Namespace AVP (AVP Code TBD) is of type Unsigned32.
3.5.2. ALRP-Priority AVP
The ALRP-Priority AVP (AVP Code TBD) is of type Unsigned32.
[RFC4412] defines a resource priority header and established the
initial registry. That registry was later extended by
[I-D.ietf-tsvwg-emergency-rsvp].
3.6. PHB-Class AVP
The PHB-Class AVP (AVP Code TBD) is of type Unsigned32.
A description of the semantic of the parameter values can be found in
[RFC3140]. The registries needed for usage with [RFC3140] already
exist and hence no new registry needs to be created by this document.
The encoding requires three cases need to be differentiated. All
bits indicated as "reserved" MUST be set to zero (0).
3.6.1. Case 1: Single PHB
As prescribed in [RFC3140], the encoding for a single PHB is the
recommended DSCP value for that PHB, left-justified in the 16 bit
field, with bits 6 through 15 set to zero.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP |0 0 0 0 0 0 0 0 0 0| (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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3.6.2. Case 2: Set of PHBs
The encoding for a set of PHBs is the numerically smallest of the set
of encodings for the various PHBs in the set, with bit 14 set to 1.
(Thus for the AF1x PHBs, the encoding is that of the AF11 PHB, with
bit 14 set to 1.)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP |0 0 0 0 0 0 0 0 1 0| (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.6.3. Case 3: Experimental or Local Use PHBs
PHBs not defined by standards action, i.e., experimental or local use
PHBs as allowed by [RFC2474]. In this case an arbitrary 12 bit PHB
identification code, assigned by the IANA, is placed left-justified
in the 16 bit field. Bit 15 is set to 1, and bit 14 is zero for a
single PHB or 1 for a set of PHBs. Bits 12 and 13 are zero.
Bits 12 and 13 are reserved either for expansion of the PHB
identification code, or for other use, at some point in the future.
In both cases, when a single PHBID is used to identify a set of PHBs
(i.e., bit 14 is set to 1), that set of PHBs MUST constitute a PHB
Scheduling Class (i.e., use of PHBs from the set MUST NOT cause
intra-microflow traffic reordering when different PHBs from the set
are applied to traffic in the same microflow). The set of AF1x PHBs
[RFC2597] is an example of a PHB Scheduling Class. Sets of PHBs that
do not constitute a PHB Scheduling Class can be identified by using
more than one PHBID.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PHD ID CODE |0 0 1 0| (Reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.7. DSTE-Class-Type AVP
The DSTE-Class-Type AVP (AVP Code TBD) is of type Unsigned32. A
description of the semantic of the parameter values can be found in
[RFC4124].
Currently, the values of alues currently allowed are 1, 2, 3, 4, 5,
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6, 7. The value of zero (0) is marked as reserved in [RFC4124].
Furthermore, the CLASSTYPE attribute in [RFC4124] is 32 bits in
length with 29 bits reserved.
4. Extensibility
This document is designed with extensibility in mind given that
different organizations and groups are used to define their own
Quality of Service parameters. This document provides an initial QoS
profile with common set of parameters. Ideally, these parameters
should be used whenever possible but there are cases where additional
parameters might be needed, or where the parameters specified in this
document are used with a different semantic. In this case it is
advisable to define a new QoS profile that may consist of new
parameters in addition to parameters defined in this document or an
entirely different set of parameters.
To enable the definition of new QoS profiles a 8 octet registry is
defined field that is represented by a 4-octet vendor and 4-octet
specifier field. The vendor field indicates the type as either
standards-specified or vendor-specific. If the four octets of the
vendor field are 0x00000000, then the value is standards-specified
and the registry is maintained by IANA as Enterprise Numbers defined
in [RFC2578], and any other value represents a vendor-specific Object
Identifier (OID). IANA created registry is split into two value
ranges; one range uses the "Standards Action" and the second range
uses "Specification Required" allocation policy. The latter range is
meant to be used by organizations outside the IETF.
5. IANA Considerations
5.1. AVP Codes
IANA is requested to allocate AVP codes for the following AVPs that
are defined in this document.
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+------------------------------------------------------------------+
| AVP Section |
|AVP Name Code Defined Data Type |
+------------------------------------------------------------------+
|TMOD-1 TBD 3.1 Grouped |
|TMOD-Rate TBD 3.1.1 Float32 |
|TMOD-Size TBD 3.1.2 Float32 |
|Peak-Data-Rate TBD 3.1.3 Float32 |
|Minimum-Policed-Unit TBD 3.1.4 Unsigned32 |
|TMOD-2 TBD 3.2 Grouped |
|Priority TBD 3.3 Grouped |
|Preemption-Priority TBD 3.3.1 Unsigned32 |
|Defending-Priority TBD 3.3.2 Unsigned32 |
|Admission-Priority TBD 3.4 Unsigned32 |
|ALRP TBD 3.5 Grouped |
|ALRP-Namespace TBD 3.5.1 Unsigned32 |
|ALRP-Priority TBD 3.5.2 Unsigned32 |
|PHB-Class TBD 3.6 Unsigned32 |
|DSTE-Class-Type TBD 3.7 Unsigned32 |
+------------------------------------------------------------------+
5.2. QoS Profile
IANA is requested to create the following registry.
The QoS Profile refers to a 64 bit long field that is represented by
a 4-octet vendor and 4-octet specifier field. The vendor field
indicates the type as either standards-specified or vendor-specific.
If the four octets of the vendor field are 0x00000000, then the value
is standards-specified and the registry is maintained by IANA, and
any other value represents a vendor-specific Object Identifier (OID).
The specifier field indicates the actual QoS profile. The vendor
field 0x00000000 is reserved to indicate that the values in the
specifier field are maintained by IANA. This document requests IANA
to create such a registry and to allocate the value zero (0) for the
QoS profile defined in this document.
For any other vendor field, the specifier field is maintained by the
vendor.
For the IANA maintained QoS profiles the following allocation policy
is defined:
0 to 511: Standards Action
512 to 4095: Specification Required
Standards action is required to depreciate, delete, or modify
existing QoS profile values in the range of 0-511 and a specification
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is required to depreciate, delete, or modify existing QoS profile
values in the range of 512-4095.
6. Security Considerations
This document does not raise any security concerns as it only defines
QoS parameters and does not yet describe how they are exchanged in a
AAA protocol. Security considerations are described in documents
using this specification.
7. Acknowledgements
The authors would like to thank the NSIS QSPEC [I-D.ietf-nsis-qspec]
authors (Cornelia Kappler, Jerry Ash, Attila Bader, Dave Oran), the
NSIS working group chairs (John Loughney and Martin Stiemerling) and
the former Transport Area Directors (Allison Mankin, Jon Peterson)
for their help. This document re-uses content from the NSIS QSPEC
[I-D.ietf-nsis-qspec] specification.
We would like to thank Ken Carlberg, Lars Eggert, Jan Engelhardt,
Francois Le Faucheur, 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.
Elwyn Davies provided a detailed review of the specification. Elwyn
helped to investigate what QoS mechanisms are deployed in networks
today. Jerry Ash, Al Morton, Mayutan Arumaithurai and Xiaoming Fu
provided help with the semantic of some QSPEC parameters.
We would like to thank Dan Romascanu for his detailed Area Director
review comments and Scott Bradner for his Transport Area Directorate
review.
8. References
8.1. Normative References
[I-D.ietf-tsvwg-emergency-rsvp]
Faucheur, F., Polk, J., and K. Carlberg, "Resource
ReSerVation Protovol (RSVP) Extensions for Emergency
Services", draft-ietf-tsvwg-emergency-rsvp-09 (work in
progress), October 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.
[RFC2215] Shenker, S. and J. Wroclawski, "General Characterization
Parameters for Integrated Service Network Elements",
RFC 2215, September 1997.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
[RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, June 1999.
[RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le Faucheur,
"Per Hop Behavior Identification Codes", RFC 3140,
June 2001.
[RFC3181] Herzog, S., "Signaled Preemption Priority Policy Element",
RFC 3181, October 2001.
[RFC4124] Le Faucheur, F., "Protocol Extensions for Support of
Diffserv-aware MPLS Traffic Engineering", RFC 4124,
June 2005.
[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
Priority for the Session Initiation Protocol (SIP)",
RFC 4412, February 2006.
8.2. Informative References
[I-D.ietf-nsis-qspec]
Bader, A., Kappler, C., and D. Oran, "QoS NSLP QSPEC
Template", draft-ietf-nsis-qspec-21 (work in 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.
[RFC2697] Heinanen, J. and R. Guerin, "A Single Rate Three Color
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Marker", RFC 2697, September 1999.
[RFC3290] Bernet, Y., Blake, S., Grossman, D., and A. Smith, "An
Informal Management Model for Diffserv Routers", RFC 3290,
May 2002.
[RFC3564] Le Faucheur, F. and W. Lai, "Requirements for Support of
Differentiated Services-aware MPLS Traffic Engineering",
RFC 3564, July 2003.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
Authors' Addresses
Jouni Korhonen (editor)
Nokia Siemens Networks
Linnoitustie 6
Espoo 02600
Finland
Email: jouni.korhonen@nsn.com
Hannes Tschofenig
Nokia Siemens Networks
Linnoitustie 6
Espoo 02600
Finland
Phone: +358 (50) 4871445
Email: Hannes.Tschofenig@gmx.net
URI: http://www.tschofenig.priv.at
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