One document matched: draft-ietf-nsis-qspec-06.txt
Differences from draft-ietf-nsis-qspec-05.txt
IETF Internet Draft NSIS Working Group Jerry Ash
Internet Draft AT&T
<draft-ietf-nsis-qspec-06.txt> Attila Bader
Expiration Date: April 2006 Ericsson
Cornelia Kappler
Siemens AG
October 2005
QoS-NSLP QSPEC Template
Status of this Memo
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Copyright Notice
Copyright (C) The Internet Society (2005).
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Internet Draft QoS-NSLP QSPEC Template October 2005
Abstract
The QoS NSLP protocol is used to signal QoS reservations and is
independent of a specific QoS model (QOSM) such as IntServ or
DiffServ. Rather, all information specific to a QOSM is encapsulated
in a separate object, the QSPEC. This draft defines a template for
the QSPEC, which contains both the QoS description and QSPEC control
information. The QSPEC format is defined, as are a number of QSPEC
parameters. The QSPEC parameters provide a common language to be
re-used in several QOSMs. To a certain extent QSPEC parameters
ensure interoperability of QOSMs. Optional QSPEC parameters aim to
ensure the extensibility of QoS NSLP to other QOSMs in the future.
The node initiating the NSIS signaling adds an Initiator QSPEC that
must not be removed, thereby ensuring the intention of the NSIS
initiator is preserved along the signaling path.
Table of Contents
1. Conventions Used in This Document . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. QSPEC Parameters, Processing, & Extensibility . . . . . . . . . 6
4.1 QSPEC Parameters . . . . . . . . . . . . . . . . . . . . . 6
4.2 QSPEC Processing . . . . . . . . . . . . . . . . . . . . . 6
4.3 Example of NSLP/QSPEC Operation . . . . . . . . . . . . . . 8
4.4 Treatment of QSPEC Parameters . . . . . . . . . . . . . . . 11
4.4.1 Mandatory and Optional QSPEC Parameters . . . . . . . 11
4.4.2 Read-only and Read-write QSPEC Parameters . . . . . . 11
4.5 Inability to handle parameters . . . . . . . . . . . . . . 12
4.5.1 Error Conditions . . . . . . . . . . . . . . . . . . 12
4.5.2 Inability to interpret and update parameters . . . . 12
4.6 QSPEC Extensibility . . . . . . . . . . . . . . . . . . . . 13
5. QSPEC Format Overview . . . . . . . . . . . . . . . . . . . . . 13
5.1 QSPEC Control Information . . . . . . . . . . . . . . . . . 14
5.2 QoS Description . . . . . . . . . . . . . . . . . . . . . . 14
5.2.1 <QoS Desired> . . . . . . . . . . . . . . . . . . . . 14
5.2.2 <QoS Available> . . . . . . . . . . . . . . . . . . . 16
5.2.3 <QoS Reserved> . . . . . . . . . . . . . . . . . . . 18
5.2.4 <Minimum QoS> . . . . . . . . . . . . . . . . . . . . 18
6. QSPEC Procedures & Examples . . . . . . . . . . . . . . . . . . 18
6.1 QSPEC Procedures . . . . . . . . . . . . . . . . . . . . . 18
6.1.1 Sender-Initiated Reservations . . . . . . . . . . . . 19
6.1.2 Receiver-Initiated Reservations . . . . . . . . . . . 20
6.1.3 Resource Queries . . . . . . . . . . . . . . . . . . 20
6.1.4 Bidirectional Reservations . . . . . . . . . . . . . 21
6.2 QSPEC Examples . . . . . . . . . . . . . . . . . . . . . . 21
7. QSPEC Functional Specification . . . . . . . . . . . . . . . . 22
7.1 General QSPEC Formats . . . . . . . . . . . . . . . . . . . 23
7.2 Parameter Coding . . . . . . . . . . . . . . . . . . . . . 25
7.2.1 <NON QOSM Hop> Parameter . . . . . . . . . . . . . . 25
7.2.2 <Excess Treatment> Parameter . . . . . . . . . . . . 26
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7.2.3 <Bandwidth> . . . . . . . . . . . . . . . . . . . . . 26
7.2.4 <Slack Term> Parameter . . . . . . . . . . . . . . . 27
7.2.5 <Token Bucket> Parameters . . . . . . . . . . . . . . 27
7.2.6 <QoS Class> Parameters . . . . . . . . . . . . . . . 28
7.2.6.1 <PHB Class> Parameter . . . . . . . . . . . . 28
7.2.6.2 <Y.1541 QoS Class> Parameter . . . . . . . . 29
7.2.6.3 <DSTE Class Type> Parameter . . . . . . . . . 30
7.2.7 Priority Parameters . . . . . . . . . . . . . . . . . 30
7.2.7.1 <Preemption Priority> & <Defending Priority>
Parameters . . . . . . . . . . . . . . . . . 30
7.2.7.2 <Reservation Priority> Parameter . . . . . . 30
7.2.8 <Path Latency> Parameter . . . . . . . . . . . . . . 32
7.2.9 <Path Jitter> Parameter . . . . . . . . . . . . . . . 33
7.2.10 <Path PLR> Parameter . . . . . . . . . . . . . . . . 33
7.2.11 <Path PER> Parameter . . . . . . . . . . . . . . . . 34
7.2.12 <Ctot> <Dtot> <Csum> <Dsum> Parameters . . . . . . . 35
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 36
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 36
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 36
11. Normative References . . . . . . . . . . . . . . . . . . . . . 36
12. Informative References . . . . . . . . . . . . . . . . . . . . 37
13. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 38
Appendix A: QoS Models and QSPECs . . . . . . . . . . . . . . . . 40
Appendix B: Mapping of QoS Desired, QoS Available and QoS Reserved
of NSIS onto AdSpec, TSpec and RSpec of RSVP IntServ . 40
Appendix C: Main Changes Since Last Version & Open Issues . . . . 41
C.1 Main Changes Since Version -04 . . . . . . . . . . 41
C.2 Open Issues . . . . . . . . . . . . . . . . . . . 41
Intellectual Property Statement . . . . . . . . . . . . . . . . . 41
Disclaimer of Validity . . . . . . . . . . . . . . . . . . . . . . 42
Copyright Statement . . . . . . . . . . . . . . . . . . . . . . . 42
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1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Introduction
The QoS NSLP establishes and maintains state at nodes along the path
of a data flow for the purpose of providing forwarding resources
(QoS) for that flow [QoS-SIG]. The design of QoS NSLP is conceptually
similar to RSVP [RFC2205], and meets the requirements of [RFC3726].
A QoS-enabled domain supports a particular QoS model (QOSM), which is
a method to achieve QoS for a traffic flow. A QOSM incorporates QoS
provisioning methods and a QoS architecture. It defines the behavior
of the resource management function (RMF), including inputs and
outputs, and how QSPEC information is interpreted on traffic
description, resources required, resources available, and control
information required by the RMF. A QOSM also specifies a set of
mandatory and optional QSPEC parameters that describe the QoS and how
resources will be managed by the RMF. QoS NSLP can support signaling
for different QOSMs, such as for IntServ, DiffServ admission control,
and those specified in [Y.1541-QOSM, INTSERV-QOSM, RMD-QOSM]. For
more information on QOSMs see Section 7.2 and Appendix A.
One of the major differences between RSVP and QoS-NSLP is that
QoS-NSLP supports signaling for different QOSMs along the data path,
all with one signaling message. For example, the data path may start
in a domain supporting DiffServ and end in a domain supporting
Y.1541. However, because some typical QoS parameters are
standardized and can be reused in different QOSMs, some degree of
interoperability between QOSMs exists.
The QSPEC travels in QoS-NSLP messages and is opaque to the QoS NSLP.
It is only interpreted by the RMF. The content of the QSPEC is QOSM
specific. Since QoS-NSLP signaling operation can be different for
different QOSMs, the QSPEC contains two kinds of information, QSPEC
control information and QoS description.
QSPEC control information contains parameters that governs the RMF.
An example of QSPEC control information is how the excess traffic is
treated in the RMF queuing functions.
The QoS description is composed of QSPEC objects loosely
corresponding to the TSpec, RSpec and AdSpec objects specified in
RSVP. This is, the QSPEC may contain a description of QoS desired
and QoS reserved. It can also collect information about available
resources. Going beyond RSVP functionality, the QoS description
also allows indicating a range of acceptable QoS by defining a QSPEC
object denoting minimum QoS. Usage of these QSPEC objects is not
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bound to particular message types thus allowing for flexibility. A
QSPEC object collecting information about available resources MAY
travel in any QoS-NSLP message, for example a QUERY message or a
RESERVE message.
3. Terminology
Mandatory QSPEC parameter: QSPEC parameter that a QNI SHOULD populate
if applicable to the underlying QOSM and a QNE MUST interpret, if
populated.
Minimum QoS: Minimum QoS is a QSPEC object that MAY be supported by
any QNE. Together with a description of QoS Desired or QoS
Available, it allows the QNI to specify a QoS range, i.e. an upper
and lower bound. If the QoS Desired cannot be reserved, QNEs are
going to decrease the reservation until the minimum QoS is hit.
Optional QSPEC parameter: QSPEC parameter that a QNI SHOULD populate
if applicable to the underlying QOSM, and a QNE SHOULD interpret if
populated and applicable to the QOSM(s) supported by the QNE. (A QNE
MAY ignore if it does not support a QOSM needing the optional QSPEC
parameter).
QNE: QoS NSIS Entity, a node supporting QoS NSLP.
QNI: QoS NSIS Initiator, a node initiating QoS-NSLP signaling.
QNR: QoS NSIS Receiver, a node terminating QoS-NSLP signaling.
QoS Description: Describes the actual QoS in QSPEC objects QoS
Desired, QoS Available, QoS Reserved, and Minimum QoS. These QSPEC
objects are input or output parameters of the RMF. In a valid QSPEC,
at least one QSPEC object of the type QoS Desired, QoS Available or
QoS Reserved MUST be included.
QoS Available: QSPEC object containing parameters describing the
available resources. They are used to collect information along a
reservation path.
QoS Desired: QSPEC object containing parameters describing the
desired QoS for which the sender requests reservation.
QoS Model (QOSM): A method to achieve QoS for a traffic flow, e.g.,
IntServ Controlled Load. A QOSM specifies a set of mandatory and
optional QSPEC parameters that describe the QoS and how resources
will be managed by the RMF. It furthermore specifies how to use QoS
NSLP to signal for this QOSM.
QoS Reserved: QSPEC object containing parameters describing the
reserved resources and related QoS parameters, for example,
bandwidth.
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QSPEC Control Information: Control information that is specific to a
QSPEC, and contains parameters that govern the RMF.
QSPEC: QSPEC is the object of QoS-NSLP containing all QOSM-specific
information.
QSPEC parameter: Any parameter appearing in a QSPEC; includes both
QoS description and QSPEC control information parameters, for
example, bandwidth, token bucket, and excess treatment parameters.
QSPEC Object: Main building blocks of QoS Description containing a
QSPEC parameter set that is input or output of an RMF operation.
Resource Management Function (RMF): Functions that are related to
resource management, specific to a QOSM. It processes the QoS
description parameters and QSPEC control parameters.
Read-only Parameter: QSPEC Parameter that is set by initiating or
responding QNE and is not changed during the processing of the QSPEC
along the path.
Read-write Parameter: QSPEC Parameter that can be changed during the
processing of the QSPEC by any QNE along the path.
4. QSPEC Parameters, Processing, & Extensibility
4.1 QSPEC Parameters
The definition of a QOSM includes the specification of how the
requested QoS resources will be described and how they will be
managed by the RMF. For this purpose, the QOSM specifies a set of
QSPEC parameters that describe the QoS and QoS resource control in
the RMF. A given QOSM defines which of the mandatory and optional
QSPEC parameters it uses, and it MAY define additional optional QSPEC
parameters. Mandatory and optional QSPEC parameters provide a common
language for QOSM developers to build their QSPECs and are likely to
be re-used in several QOSMs. Mandatory and optional QSPEC parameters
are defined in this document, and additional optional QSPEC
parameters can be defined in separate documents. Specification of
additional optional QSPEC parameters requires standards action, as
defined in Section 4.5.
4.2 QSPEC Processing
The QSPEC is opaque to the QoS-NSLP processing. The QSPEC control
information and the QoS description are interpreted and MAY be
modified by the RMF in a QNE (see description in [QoS-SIG]).
A QoS-enabled domain supports a particular QOSM, e.g. DiffServ
admission control. If this domain supports QoS-NSLP signaling, its
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QNEs MUST support the DiffServ admission control QOSM. The QNEs MAY
also support additional QOSMs.
A QoS NSLP message can contain a stack of at most 2. The first on
the stack is the Initiator QSPEC. This is a QSPEC provided by the
QNI, which travels end-to-end, and therefore the stack always has at
least depth 1. QSPEC parameters MUST NOT be deleted from or added to
the Initiator QSPEC. In addition, the stack MAY contain a Local
QSPEC stacked on top of the Initiator QSPEC. A QNE only considers
the topmost QSPEC.
At the ingress edge of a local QoS domain, a Local QSPEC MAY be
pushed on the stack in order to describe the requested resources in a
domain-specific manner. Also, the Local QSPEC is popped from the
stack at the egress edge of the local QoS domain.
This draft provides a template for the QSPEC, which is needed in
order to help define individual QOSMs and in order to promote
interoperability between QOSMs. Figure 1 illustrates how the QSPEC
is composed of QSPEC control information and QoS description. QoS
description in turn is composed of up to four QSPEC objects (not all
of them need to be present), namely QoS Desired, QoS Available, QoS
Reserved and Minimum QoS. Each of these QSPEC Objects, as well as
QSPEC Control Information, consists of a number of mandatory and
optional QSPEC parameters.
+-------------+---------------------------------------+
|QSPEC Control| QoS |
| Information | Description |
+-------------+---------------------------------------+
\________________ ______________________/
V
+----------+----------+---------+-------+ \
|QoS Desir.|QoS Avail.|QoS Rsrv.|Min QoS| > QSPEC
+----------+----------+---------+-------+ / Objects
\_______ ____/\____ ____/\___ _____/\___ ____/\__ ___/
V V V V V
+-------------+... +-------------+...
|QSPEC Para. 1| |QSPEC Para. n|
+-------------+... +-------------+...
Figure 1: Structure of the QSPEC
The internal structure of each QSPEC object and the QSPEC control
information, with mandatory and optional parameters, is illustrated
in Figure 2.
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+------------------+-----------------+---------------+
| QSPEC/Ctrl Info | Mandatory QSPEC |Optional QSPEC |
| Object ID | Parameters | Parameters |
+------------------+-----------------+---------------+
Figure 2: Structure of QSPEC Objects & Control Information
4.3 Example of NSLP/QSPEC Operation
This Section illustrates the operation and use of the QSPEC within
the NSLP. The example configuration in shown in Figure 3.
+----------+ /-------\ /--------\ /--------\
| Laptop | | Home | | Cable | | DiffServ |
| Computer |-----| Network |-----| Network |-----| Network |----+
+----------+ | No QOSM | |DQOS QOSM | | RMD QOSM | |
\-------/ \--------/ \--------/ |
|
+-----------------------------------------------+
|
| /--------\ +----------+
| | "X"G | | Handheld |
+---| Wireless |-----| Device |
| XG QOSM | +----------+
\--------/
Figure 3: Example Configuration to Illustrate QoS-NSLP/QSPEC
Operation
In this configuration, a laptop computer and a handheld wireless
device are the endpoints for some application that has QoS
requirements. Assume initially that the two endpoints are stationary
during the application session, later we consider mobile endpoints.
For this session, the laptop computer is connected to a home network
that has no QoS support. The home network is connected to a
CableLabs-type cable access network with dynamic QoS (DQOS) support,
such as specified in the 'CMS to CMS Signaling Specification' [CMSS]
for cable access networks. That network is connected to a DiffServ
core network that uses the RMD QOSM [RMD-QOSM]. On the other side of
the DiffServ core is a wireless access network built on generation
"X" technology with QoS support as defined by generation "X". And
finally the handheld endpoint is connected to the wireless access
network.
We assume that the Laptop is the QNI and handheld device is the QNR.
The QNI will populate an Initiator QSPEC to achieve the QoS desired
on the path. In this example we consider two different ways to
perform sender-initiated signaling for QoS:
Case 1) The QNI sets <QoS Desired>, <QoS Available> and possibly
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<Minimum QoS> QSPEC objects in the Initiator QSPEC, and initializes
<QoS Available> to <QoS Desired>. Since this is a reservation in a
heterogenic network with different QOSMs supported in different
domains, each QNE on the path reads and interprets those parameters
in the Initiator QSPEC that it needs to implement the QOSM within its
domain (as described below). Each QNE along the path checks to see if
<QoS Available> resources can be reserved, and if not, the QNE
reduces the respective parameter values in <QoS Available> and
reserves these values. The minimum parameter values are given in
<Minimum QoS>, if populated, otherwise zero if <Minimum QoS> is not
included. If one or more parameters in <Available QoS> fails to
satisfy the corresponding minimum values in Minimum QoS, the QNE
notifies the QNI and the reservation is aborted. Otherwise, the QNR
notifies the QNI of the <QoS Available> for the reservation.
Case 2) The QNI populated the Initiator QSPEC with <QoS Desired>.
Since this is a reservation in a heterogenic network with different
QOSMs supported in different domains, each QNE on the path reads and
interprets those parameters in the Initiator QSPEC that it needs to
implement the QOSM within its domain (as described below). If a QNE
cannot reserve <QoS Desired> resources, the reservation fails.
In both cases, the QNI populates mandatory and optional QSPEC to
ensure correct treatment of its traffic in domains down the path.
Since the QNI does not know the QOSM used in downstream domains, it
includes values for those mandatory and optional QSPEC parameters it
cares about. Let us assume the QNI wants to achieve IntServ-like QoS
guarantees, and also is interested in what path latency it can
achieve. The QNI therefore includes in the QSPEC the QOSM ID for
IntServ Controlled Load Service. The QSPEC objects are populated with
all parameters necessary for IntServ Controlled Load and additionally
the parameter to measure path latency, as follows:
<QoS Desired> = <Token Bucket>
<QoS Available> = <Token Bucket> <Path Latency>
In both cases, each QNE on the path reads and interprets those
parameters in the Initiator QSPEC that it needs to implement the QOSM
within its domain. It may need additional parameters for its QOSM,
which are not specified in the Initiator QSPEC. If possible, these
parameters must be inferred from those that are present, according to
rules defined in the QOSM implemented by this QNE.
There are two possibilities when a RESERVE message is received at a
QNE at a domain border (we illustrate both possibilities in the
example):
- the QNE can stack a local QSPEC on top of the Initiator QSPEC (this
is new in QoS NSLP, RSVP does not do this).
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- the QNE can tunnel the Initiator RESERVE message through its domain
and issue its own Local RESERVE message. For this new Local RESERVE
message, the QNE acts as the QNI, and the QSPEC in the domain is an
Initiator QSPEC. This procedure is also used by RSVP in making
aggregate reservations, in which case there is not a new intra-domain
(aggregate) RESERVE for each newly arriving interdomain (per-flow)
RESERVE, but the aggregate reservation is updated by the border QNE
(QNI) as need be. This is also how RMD works [RMD-QOSM].
For example, at the RMD domain, a local RESERVE with its own RMD
Initiator QSPEC corresponding to the RMD-QOSM is generated based on
the original Initiator QSPEC according to the procedures described in
Section 4.5 of [QoS-SIG] and in [RMD-QOSM]. That is, the ingress QNE
to the RMD domain must map the QSPEC parameters contained in the
original Initiator QSPEC into the RMD QSPEC. The RMD QSPEC for
example needs <Bandwidth> and <QoS Class>. <Bandwidth> is generated
from the <Token Bucket> parameter. Information on <QoS Class>,
however, is not provided. According to the rules laid out in the RMD
QOSM, the ingress QNE infers from the fact that an IntServ Controlled
Load QOSM was signaled that the EF PHB is appropriate to set the <PHB
Class> parameter. These RMD QSPEC parameters are populated in the
RMD Initiator QSPEC generated within the RMD domain.
Furthermore, the node at the egress to the RMD domain updates <QoS
Available> on behalf of the entire RMD domain if it can. If it
cannot, it raises the parameter-specific, 'not-supported' flag,
warning the QNR that the final value of these parameters in QoS
Available is imprecise.
In the XG domain, the Initiator QSPEC is translated into a Local
QSPEC using a similar procedure as described above. The Local QSPEC
becomes the current QSPEC used within the XG domain, that is, the
it becomes the first QSPEC on the stack, and the Initiator QSPEC is
second. This saves the QNEs within the XG domain the trouble of
re-translating the Initiator QSPEC. At the egress edge of the XG
domain, the translated Local QSPEC is popped, and the Initiator QSPEC
returns to the number one position.
If the reservation was successful, eventually the RESERVE request
arrives at the QNR (otherwise the QNE at which the reservation failed
would have aborted the RESERVE and sent an error RESPONSE back to the
QNI). The QNR generates a positive RESPONSE with QSPEC objects <QoS
Reserved> - and for case 1 - additionally <QoS Available>. The
parameters appearing in <QoS Reserved> are the same as in <QoS
Desired>, with values copied from <QoS Available> in case 1, and with
the original values from <QoS Desired> in case 2. That is, it is not
necessary to transport the <QoS Desired> object back to the QNI since
the QNI knows what it signaled originally, and the information is not
useful for QNEs in the reverse direction. The <QoS Reserved> object
should transport all necessary information, although the <QoS
Available> and <QoS Reserved> objects may end up transporting some of
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the same information.
Hence, the QNR populates the following QSPEC objects:
<QoS Reserved> = <Token Bucket>
<QoS Available> = <Token Bucket> <Path Latency>
If the handheld device on the right of Figure 3 is mobile, and moves
through different "XG" wireless networks, then the QoS might change
on the path since different XG wireless networks might support
different QOSMs. As a result, QoS-NSLP/QSPEC processing will have to
renegotiate the <QoS Available> on the path. From a QSPEC
perspective, this is like a new reservation on the new section of the
path and is basically the same as any other rerouting event - to the
QNEs on the new path it looks like a new reservation. That is, in
this mobile scenario, the new segment may support a different QOSM
than the old segment, and the QNI would now signal a new reservation
(explicitly, or implicitly with the next refreshing RESERVE message)
to account for the different QOSM in the XG wireless domain. Further
details on rerouting are specified in [QoS-SIG].
4.4 Treatment of QSPEC Parameters
4.4.1 Mandatory and Optional QSPEC Parameters
Mandatory and optional QSPEC parameters are defined in this document
and are applicable to a number of QOSMs. Mandatory QSPEC parameters
are treated as follows:
o A QNI SHOULD populate mandatory QSPEC parameters if applicable to
the underlying QOSM.
o QNEs MUST interpret mandatory QSPEC parameters, if populated.
Optional QSPEC parameters are treated as follows:
o A QNI SHOULD populate optional QSPEC parameters if applicable to
the QOSM for which it is signaling.
o QNEs SHOULD interpret optional QSPEC parameters, if populated and
applicable to the QOSM(s) supported by the QNE. (A QNE MAY ignore
the optional QSPEC parameter if it does not support a QOSM needing
the optional QSPEC parameter).
4.4.2 Read-only and Read-write QSPEC Parameters
Both mandatory and optional QSPEC parameters can be read-only or
read-write. Read-write parameters can be changed by any QNE, whereas
read-only parameters are fixed by the QNI and/or QNR. For example in
a RESERVE message, all parameters in <QoS Available> are read-write
parameters, which are updated by intermediate QNEs. Read-only
parameters are, for example, all parameters in <QoS Desired> as sent
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by the QNI.
QoS description parameters can be both read-only or read-write,
depending on which QSPEC object, and which message, they appear in.
In particular, all parameters in <QoS Desired> and <Minimum QoS> are
read-only for all messages. More details are provided in Sec. 7.1.
In the QSPEC Control Information Object, the property of being
read-write or read-only is parameter specific.
4.5 Inability to handle parameters
A QNE may not be able to interpret or update the QSPEC or individual
parameters for several reasons. For example, the QSPEC cannot be
read or interpreted because it is erroneous, or because of a QNE
fault. This is an error condition. Another reason is that a
parameter type is unknown because it is optional, or a parameter
value in QoS Available cannot be updated because QoS NSLP was
tunneled to the QNE. These are not error conditions.
4.5.1 Error Conditions
When an RMF cannot interpret the QSPEC because the coding is
erroneous, it raises corresponding flags in the QSPEC. A more
detailed report of the problem is provided in QoS NSLP. That is, the
'error flags' are located in each QSPEC Object and in each parameter.
If such a flag is set, at least one QNE along the data transmission
path between the QNI and QNR cannot interpret a mandatory or optional
QSPEC parameter or the QSPEC object for any reason, such as a
protocol error, QNE fault, etc. In this case, more detailed error
information may be given in the QoS NSLP error message. That is, if
possible the RMF must communicate error details to the QoS NSLP
processing. QoS NSLP [QoS-SIG] describes how the erroneous message
is handled further.
When the error can be located in a particular parameter, the QNE
detecting the error raises the error flag in this parameter.
Additionally, it raises the error flag in the corresponding QSPEC
Object. If the error cannot be located at the parameter level, only
the error flag in the QSPEC object is raised.
4.5.2 Inability to interpret and update parameters
Each QSPEC parameter has an associated 'not-supported flag'. If such
a flag is set, at least one QNE along the data transmission path
between the QNI and QNR can not support the specified QSPEC
parameter. The not-supported flag is set to 1 if an optional QSPEC
parameter is not supported by a QNE. If the not-supported flag is
set, then at least one QNE along the data transmission path between
the QNI and QNR can not support the specified optional parameter.
This means the value collected in the corresponding parameter is a
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lower bound to the "real" value. A QNE MUST be able to set the
not-supported flag if it does not support the optional parameter.
Each QSPEC parameter has an associated 'tunneled-parameter flag',
which is set to 1 if a mandatory or optional QSPEC parameter is
tunneled through a QOSM domain, and the edge node is unable to set
the QSPEC parameter. When a RESERVE message is tunneled through a
domain, QNEs inside the domain cannot update read-write parameters.
The egress QNE in a domain has two choices: either it is configured
to have the knowledge to update the parameters correctly. Or it
cannot update the parameters. In this case it MUST set the
tunneled-parameter flag to tell the QNI (or QNR) that the information
contained in the read-write parameter is most likely incorrect (or a
lower bound).
The formats and semantics of all flags are given in Section 6.1.
4.6 QSPEC Extensibility
Additional optional QSPEC parameters MAY need to be defined in the
future. Additional optional QSPEC parameters are defined in separate
Informational documents specific to a given QOSM. For example,
optional QSPEC parameters are defined in [RMD-QOSM] and
[Y.1541-QOSM].
5. QSPEC Format Overview
QSPEC = <QSPEC Version> <QOSM ID> <QSPEC Control Information>
<QoS Description>
As described above, the QSPEC contains an identifier for the QOSM,
the actual resource description (QoS description) as well as QSPEC
control information. Note that all QSPEC parameters defined in the
following Sections are mandatory QSPEC parameters unless specifically
designated as optional QSPEC parameters.
A QSPEC object ID identifies whether the object is <QSPEC Control
Information> or <QoS Description>. As described below, the <QoS
Description> is further broken down into <QoS Desired>, <QoS
Available>, <QoS Reserved>, and <Minimum QoS> objects. A QSPEC
parameter ID is assigned to identify each QSPEC parameter defined
below.
<QSPEC Version> identifies the QSPEC version number, and <QOSM ID>
identifies the particular QOSM being used by the QNI (the QSPEC
Version and QOSM ID are assigned by IANA). The <QOSM ID> tells a QNE
which parameters to expect. This may simplify processing and error
analysis. Furthermore, it may be helpful for a QNE or a domain
supporting more than one QOSM to learn which QOSM the QNI would like
to have in order to use the most suitable QOSM. Note that the QSPEC
parameters do not uniquely define the QNI QOSM since more parameters
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than required by the QNI QOSM can be included by the QNI. QOSM IDs
are assigned by IANA.
5.1 QSPEC Control Information
QSPEC control information is used for signaling QOSM RMF functions
not defined in QoS-NSLP. It enables building new RMF functions
required by a QOSM within a QoS-NSLP signaling framework, such as
specified, for example, in [RMD-QOSM] and [Y.1541-QOSM].
<QSPEC Control Information> = <QSPEC Procedure Identifier>
<NON QOSM Hop> <Excess Treatment>
Note that <NON QOSM Hop> is a read-write parameter. <QSPEC Procedure
Identifier> and <Excess Treatment> are read-only parameters.
<QSPEC Procedure Identifier> is an identifier for which QSPEC
procedures are used, as defined in Section 7.1.
<NON QOSM Hop> is a flag bit telling the QNR (or QNI in a RESPONSE
message) whether or not a particular QOSM is supported by each QNE
in the path between the QNI and QNR. A QNE sets the <NON QOSM Hop>
flag parameter if it does not support the relevant QOSM
specification. If the QNR finds this bit set, at least one QNE along
the data transmission path between the QNI and QNR can not support
the specified QOSM.In a local QSPEC, <NON QOSM Hop> refers to the
QoS-NSLP peers of the local QOSM domain.
The <Excess Treatment> parameter describes how the QNE will process
excess traffic, that is, out-of-profile traffic. Excess traffic MAY
be dropped, shaped and/or remarked. The excess treatment parameter is
initially set by the QNI and is read-only.
5.2 QoS Description
The QoS Description is broken down into the following QSPEC objects:
<QoS Description> = <QoS Desired> <QoS Available> <QoS Reserved>
<Minimum QoS>
Of these QSPEC objects, QoS Desired, QoS Available and QoS Reserved
MUST be supported by QNEs. Minimum QoS MAY be supported.
5.2.1 <QoS Desired>
<QoS Desired> = <Traffic Description> <QoS Class> <Priority>
<Path Latency> <Path Jitter> <Path PLR> <Path PER>
These parameters describe the resources the QNI desires to reserve
and hence this is a read-only QSPEC object. The <QoS Desired>
resources that the QNI wishes to reserve are of course directly
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related to the traffic the QNI is going to inject into the network.
Therefore, when used in the <QoS Desired> object, <Traffic
Description> refers to traffic injected by the QNI into the network.
<Traffic Description> = <Bandwidth> <Token Bucket>
<Bandwidth> = link bandwidth needed by flow [RFC 2212, RFC 2215]
<Token Bucket> = <r> <b> <p> <m> <MTU> [RFC 2210]
Note that the Path MTU Discovery (PMTUD) working group is currently
specifying a robust method for determining the MTU supported over an
end-to-end path. This new method is expected to update RFC1191 and
RFC1981, the current standards track protocols for this purpose.
<QoS Class> = <PHB Class> <Y.1541 QoS Class> <DSTE Class Type>
An application MAY like to reserve resources for packets with a
particular QoS class, e.g. a DiffServ per-hop behavior (PHB)
[RFC2475], or DiffServ-enabled MPLS traffic engineering (DSTE) class
type [RFC3564].
<Priority> = <Reservation Priority> <Preemption Priority>
<Defending Priority>
<Reservation priority> is an essential way to differentiate flows for
emergency services, ETS, E911, etc., and assign them a higher
admission priority than normal priority flows and best-effort
priority flows. <Preemption Priority> is the priority of the new
flow compared with the defending priority of previously admitted
flows. Once a flow is admitted, the preemption priority becomes
irrelevant. <Defending Priority> is used to compare with the
preemption priority of new flows. For any specific flow, its
preemption priority MUST always be less than or equal to the
defending priority.
Appropriate security measures need to be taken to prevent abuse of
the <Priority> parameters, see Section 8 on Security Considerations.
[Y.1540] defines packet transfer outcomes, as follows:
Successful: packet arrives within the preset waiting time with no
errors
Lost: packet fails to arrive within the waiting time
Errored: packet arrives in time, but has one or more bit errors
in the header or payload
Packet Loss Ratio (PLR) = total packets lost/total packets sent
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Packet Error Ratio (PER) = total errored packets/total packets sent
<Path Latency>, <Path Jitter>, <Path PLR>, and <Path PER> are
optional parameters describing the desired path latency, path jitter
and path bit error rate respectively. Since these parameters are
cumulative, an individual QNE cannot decide whether the desired path
latency, etc., is available, and hence they cannot decide whether a
reservation fails. Rather, when these parameters are included in
<Desired QoS>, the QNI SHOULD also include corresponding parameters
in a <QoS Available> QSPEC object in order to facilitate collecting
this information.
5.2.2 <QoS Available>
QNE MUST inspect all parameters of this QSPEC object, and if
resources available to this QNE are less than what a particular
parameter says currently, the QNE MUST adapt this parameter
accordingly. Hence when the message arrives at the recipient of the
message, <QoS Available> reflects the bottleneck of the resources
currently available on a path. It can be used in a QUERY message,
for example, to collect the available resources along a data path.
When <QoS Available> travels in a RESPONSE message, it in fact just
transports the result of a previous measurement performed by a
RESERVE or QUERY message back to the initiator. Therefore in this
case, <QoS Available> is read-only.
The parameters <Token Bucket> and <Bandwidth> provide information,
for example, about the bandwidth available along the path followed by
a data flow. The local parameter is an estimate of the bandwidth the
QNE has available for packets following the path. Computation of the
value of this parameter SHOULD take into account all information
available to the QNE about the path, taking into consideration
administrative and policy controls on bandwidth, as well as physical
resources. The composition rule for this parameter is the MIN
function. The composed value is the minimum of the QNE's value and
the previously composed value. This quantity, when composed
end-to-end, informs the QNR (or QNI in a RESPONSE message) of the
minimal bandwidth link along the path from QNI to QNR.
The <Path Latency> parameter accumulates the latency of the packet
forwarding process associated with each QNE, where the latency is
defined to be the mean packet delay added by each QNE. This delay
results from speed-of-light propagation delay, from packet processing
limitations, or both. It does not include any variable queuing delay
that may be present. Each QNE MUST add the propagation delay of its
outgoing link, which includes the QNR adding the associated delay for
the egress link. Furthermore, the QNI MUST add the propagation delay
of the ingress link. The composition rule for the <Path Latency>
parameter is summation with a clamp of (2**32 - 1) on the maximum
value. This quantity, when composed end-to-end, informs the QNR (or
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QNI in a RESPONSE message) of the minimal packet delay along the path
from QNI to QNR. The purpose of this parameter is to provide a
minimum path latency for use with services which provide estimates or
bounds on additional path delay [RFC 2212]. Together with the
queuing delay bound, this parameter gives the application knowledge
of both the minimum and maximum packet delivery delay. Knowing both
the minimum and maximum latency experienced by data packets allows
the receiving application to know the bound on delay variation and
de-jitter buffer requirements.
The <Path Jitter> parameter accumulates the jitter of the packet
forwarding process associated with each QNE, where the jitter is
defined to be the nominal jitter added by each QNE. IP packet
jitter, or delay variation, is defined in [RFC3393], Section 3.4
(Type-P-One-way-ipdv), and where the selection function includes the
packet with minimum delay such that the distribution is equivalent to
2-point delay variation in [Y.1540]. The suggested evaluation
interval is 1 minute. Note that the method to estimate IP delay
variation without active measurements requires more study. This
jitter results from packet processing limitations, and includes any
variable queuing delay which may be present. Each QNE MUST add the
jitter of its outgoing link, which includes the QNR adding the
associated jitter for the egress link. Furthermore, the QNI MUST
add the jitter of the ingress link. The composition method for the
<Path Jitter> parameter is the combination of several statistics
describing the delay variation distribution with a clamp on the
maximum value (note that the methods of accumulation and estimation
of nominal QNE jitter are under study). This quantity, when composed
end-to-end, informs the QNR (or QNI in a RESPONSE message) of the
nominal packet jitter along the path from QNI to QNR. The purpose of
this parameter is to provide a nominal path jitter for use with
services that provide estimates or bounds on additional path delay
[RFC2212]. Together with the <Path Latency> and the queuing delay
bound, this parameter gives the application knowledge of the typical
packet delivery delay variation.
The <Path PLR> parameter accumulates the packet loss rate (PLR) of
the packet forwarding process associated with each QNE, where the PLR
is defined to be the PLR added by each QNE. Each QNE MUST add the
PLR of its outgoing link, which includes the QNR adding the
associated PLR for the egress link. Furthermore, the QNI MUST add
the PLR of the ingress link. The composition rule for the <Path
PLR> parameter is summation with a clamp on the maximum value (this
assumes sufficiently low PLR values such that summation error is not
significant). This quantity, when composed end-to-end, informs the
QNR (or QNI in a RESPONSE message) of the minimal packet PLR along
the path from QNI to QNR. As with <Path Jitter>, the method to
estimate <Path PLR> requires more study.
<Ctot>, <Dtot>, <Csum>, <Dsum>: Error terms C and D represent how the
element's implementation of the guaranteed service deviates from the
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fluid model. These two parameters have an additive composition rule.
The error term C is the rate-dependent error term. It represents the
delay a datagram in the flow might experience due to the rate
parameters of the flow. The error term D is the rate-independent,
per-element error term and represents the worst case non-rate-based
transit time variation through the service element. If the
composition function is applied along the entire path to compute the
end-to-end sums of C and D (<Ctot> and <Dtot>) and the resulting
values are then provided to the QNR (or QNI in a RESPONSE message).
<Csum> and <Dsum> are the sums of the parameters C and D between the
last reshaping point and the current reshaping point.
5.2.3 <QoS Reserved>
<QoS Reserved> = <Traffic Description> <QoS Class> <Priority> <S>
These parameters describe the QoS reserved by the QNEs along the data
path, and hence the QoS reserved QSPEC object is read-write.
<Traffic Description>, <QoS Class> and <Priority> are defined above.
<S> = slack term, which is the difference between desired delay and
delay obtained by using bandwidth reservation, and which is used to
reduce the resource reservation for a flow [RFC 2212]. This is an
optional parameter.
5.2.4 <Minimum QoS>
<Minimum QoS> = <Traffic Description> <QoS Class> <Priority>
<Minimum QoS> does not have an equivalent in RSVP. It allows the QNI
to define a range of acceptable QoS levels by including both the
desired QoS value and the minimum acceptable QoS in the same message.
It is a read-only QSPEC object. The desired QoS is included with a
<QoS Desired> and/or a <QoS Available> QSPEC object seeded to the
desired QoS value. The minimum acceptable QoS value MAY be coded in
the <Minimum QoS> QSPEC object. As the message travels towards the
QNR, <QoS Available> is updated by QNEs on the path. If its value
drops below the value of <Minimum QoS> the reservation fails and is
aborted. When this method is employed, the QNR SHOULD signal back to
the QNI the value of <QoS Available> attained in the end, because the
reservation MAY need to be adapted accordingly.
6. QSPEC Procedures & Examples
6.1 QSPEC Procedures
While the QSPEC template aims to put minimal restrictions on usage of
QSPEC objects in <QoS Description>, interoperability between QNEs and
between QOSMs must be ensured. We therefore give below an exhaustive
list of QSPEC object combinations for the message sequences described
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in QoS NSLP [QOS-SIG]. A specific QOSM may impose more restrictions
on the QNI or QNR freedom.
6.1.1 Sender-Initiated Reservations
Here the QNI issues a RESERVE, which is replied to by a RESPONSE.
This response is generated either by the QNR or, in case the
reservation was unsuccessful, by a QNE. The following possibilities
for QSPEC object usage exist:
ID | RESERVE | RESPONSE
---------------------------------------------------------------
1 | QoS Desired | QoS Reserved
2 | QoS Desired, QoS Avail. | QoS Reserved, QoS Avail.
3 | QoS Desired, QoS Avail., Min. QoS | QoS Reserved, QoS Avail.
(1) If only QoS Desired is included in the RESERVE, the implicit
assumption is that exactly these resources must be reserved. If this
is not possible the reservation fails. The parameters in QoS
Reserved are copied from the parameters in QoS Desired.
(2) When QoS Available is included in the RESERVE also, some
parameters will appear only in QoS Available and not in QoS Desired.
It is assumed that the value of these parameters is collected for
informational purposes only (e.g. path latency).
However, some parameters in QoS Available can be the same as in QoS
Desired. For these parameters the implicit message is that the QNI
would be satisfied by a reservation with lower parameter values than
specified in QoS Desired. For these parameters, the QNI seeds the
parameter values in QoS Available to those in QoS Desired (except for
cumulative parameters such as <path latency>).
Each QNE adapts the parameters in QoS Available according to its
current capabilities. Reservations in each QNE are hence based on
current parameter values in QoS Available (and additionally those
parameters that only appear in QoS Desired). The drawback of this
approach is that, if the resulting resource reservation becomes
gradually smaller towards the QNR, QNEs close to the QNI have an
oversized reservation, possibly resulting in unnecessary costs for
the user. Of course, in the RESPONSE the QNI learns what the actual
reservation is (from the QoS RESERVED object) and can immediately
issue a properly sized refreshing RESERVE. The advantage of the
approach is that the reservation is performed in half-a-roundtrip
time.
The parameter types included in QoS Reserved in the RESPONSE MUST be
the same as those in QoS Desired in RESERVE. For those parameters
that were also included in QoS Available in RESERVE, their value is
copied into QoS Desired. For the other parameters, the value is
copied from QoS Desired (the reservation would fail if the
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corresponding QoS could not be reserved).
The parameters in the QoS Available QSPEC object in the RESPONSE are
copied with their values from the QoS Available QSPEC object in the
RESERVE. Note that the parameters in QoS Available are read-write
in the RESERVE message, whereas they are read-only in the RESPONSE.
(3) this case is handled as case (2), except that the reservation
fails when QoS Available becomes less than Minimum QoS for one
parameter. If a parameter appears in QoS Available but not in
Minimum QoS it is assumed that the minimum value for this parameter
is that given in QoS Available.
6.1.2 Receiver-Initiated Reservations
Here the QNR issues a QUERY which is replied to by the QNI with a
RESERVE if the reservation was successful. The QNR in turn sends a
RESPONSE to the QNI.
ID| QUERY | RESERVE | RESPONSE
---------------------------------------------------------------------
1 |QoS Des. | QoS Des. | QoS Res.
2 |QoS Des.,Min. QoS | QoS Des.,QoS Avl.,(Min QoS)| QoS Res.,QoS Avl.
3 |QoS Avail. | QoS Des. | QoS Res.
(1) and (2) The idea is that the sender (QNR in this scenario) needs
to inform the receiver (QNI in this scenario) about the QoS it
desires. To this end the sender sends a QUERY message to the
receiver including a QoS Desired QSPEC object. If the QoS is
negotiable it additionally includes a (possibly zero) Minimum QoS, as
in Case b.
The RESERVE message includes QoS Available if the sender signaled QoS
is negotiable (i.e. it included Minimum QoS). If the Minimum QoS
received from the sender is non-zero, the QNR also includes Minimum
QoS.
(3) This is the "RSVP-style" scenario. The sender (QNR) issues a
QUERY with QoS Available to collect path properties, and the QoS
Desired in the RESERVE issued by the receiver (QNI) is populated from
the parameter values in QoS Available from the QUERY message. The
advantage of this model is that the situation of over-reservation in
QNEs close to the QNI as described above does not occur. On the
other hand, the QUERY may find, for example, a particular bandwidth
is not available. When the actual reservation is performed, however,
the desired bandwidth may meanwhile have become free. That is, the
'RSVP style' may result in a smaller reservation than necessary.
6.1.3 Resource Queries
Here the QNI issues a QUERY in order to investigate what resources
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are currently available. The QNR replies with a RESPONSE.
ID | QUERY | RESPONSE
--------------------------------------------
1 | QoS Available | QoS Available
Note QoS Available when traveling in the QUERY is read-write, whereas
in the RESPONSE it is read-only.
6.1.4 Bidirectional Reservations
On a QSPEC level, bidirectional reservations are no different from
uni-directional reservations, since QSPECs for different directions
never travel in the same message.
6.2 QSPEC Examples
This Section provides an example QSPEC for DiffServ admission
control. The QSPEC for IntServ controlled load service is
specified in [INTSERV-QOSM] (note that the QOSMs for IntServ
Controlled Load Service and IntServ Guaranteed Service are defined in
[RFC2211] and [RFC2212], respectively).
The QSPEC for DiffServ admission control may be composed, for
example, of the QSPEC objects <QoS Desired> and <QoS Available>, as
well as <QoS Reserved>. Which QSPEC object is present in a
particular QSPEC depends on the message type (RESERVE, QUERY etc) in
which the QSPEC travels. Parameters in the QSPEC for DiffServ
requesting bandwidth for different PHBs are as follows:
Example QSPEC for the DiffServ EF PHB [RFC3297]:
<QSPEC Control Information> = <Excess Treatment>
<QoS Description> = <QoS Desired> <QoS Available> <QoS Reserved>
<QoS Desired> = <Traffic Description> <QoS Class>
<Traffic Description> = <Token Bucket>
<QoS class> = <PHB Class=EF>
<QoS Available> = <Token Bucket>
<QoS Reserved> = <Token Bucket>
In general, the EF PHB is a property of the service that is NOT
dependent on the input traffic characteristics. A server of rate R
and latency E that is compliant with the EF PHB must deliver at least
the configured service rate R with at most latency E for any traffic
characterization. Therefore, strictly speaking, there is no specific
traffic descriptor required to deliver the EF PHB (which by
definition is a local per-hop characterization). However, in order
to deliver a reasonable end-to-end delay, it is typically assumed
that EF traffic is shaped at the ingress. A typical assumption is
that input traffic at any ingress is constrained by a single rate
token bucket. Therefore, a single rate token bucket is sufficient
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to signal in QoS-NSLP/QSPEC for the DiffServ-QOSM.
Example QSPEC for the DiffServ AFxy PHB [RFC2597]:
<QSPEC Control Information> = <Excess Treatment>
<QoS Description> = <QoS Desired> <QoS Available> <QoS Reserved>
<QoS Desired> = <Traffic Description> <QoS Class>
<Traffic Description> = <Committed Burst Size (CBS) Token Bucket>
<Excess Burst Size (EBS) Token Bucket>
<QoS class> = <PHB Class=AFxy>
<QoS Available> = <CBS Token Bucket> <EBS Token Bucket>
<QoS Reserved> = <CBS Token Bucket> <EBS Token Bucket>
QNEs process two sets of token bucket parameters to implement the
DiffServ AF QOSM, one token bucket for the average (CBS) traffic and
one token bucket for the burst (EBS) traffic. These 2 token buckets
are sufficient to cover most of the ways in which one would
distinguish among 3 levels of drop precedence at the queuing
mechanics level, as described in the Appendix to [RFC2597].
QoS-NSLP/QSPEC can support signaling the parameters required for the
DiffServ marker elements described in [RFC2697] and [RFC2698].
[RFC2697] defines a Single Rate Three Color Marker (srTCM), which
can be used as component in a DiffServ traffic conditioner [RFC2475,
RFC2474]. The srTCM 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.
RFC 2697 and RFC 2698 provide specific procedures, where in essence,
RFC 2697 is using two token buckets that run at the same rate.
7. QSPEC Functional Specification
This Section defines the encodings of the QSPEC parameters and QSPEC
control information defined in Section 5. We first give the general
QSPEC formats and then the formats of the QSPEC objects and
parameters.
Note that all QoS Description parameters can be either read-write or
read-only, depending on which object and which message they appear
in. However, in a given QSPEC object, all objects are either
read-write or read-only. In order to simplify keeping track of
whether an object is read-write or read-only, a corresponding flag is
associated with each object.
Network byte order ('big-endian') for all 16- and 32-bit integers, as
well as 32-bit floating point numbers, are as specified in [RFC1832,
IEEE754, NETWORK-BYTE-ORDER].
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7.1 General QSPEC Formats
The format of the QSPEC closely follows that used in GIST [GIST] and
QoS NSLP [QoS-SIG]. Every object (and parameter) has the following
general format:
o The overall format is Type-Length-Value (in that order).
o Some parts of the type field are set aside for control flags.
o Length has the units of 32-bit words, and measures the length of
Value. If there is no Value, Length=0.
o Value is a whole number of 32-bit words. If there is any padding
required, the length and location MUST be defined by the
object-specific format information; objects that contain variable
length types may need to include additional length subfields to do
so.
o Any part of the object used for padding or defined as reserved("r")
MUST be set to 0 on transmission and MUST be ignored on reception.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Common QSPEC Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// QSPEC Control Information //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// QSPEC QoS Objects //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Common QSPEC Header is a fixed 4-byte long object containing the
QOSM ID and an identifier for the QSPEC Procedure (see Section 6.1):
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Vers. | QOSM ID | QSPEC Proc. | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that a length field is not necessary since the overall length of
the QSPEC is contained in the higher level QoS NSLP data object.
Vers.: Identifies the QSPEC version number. It is assigned by IANA.
QOSM ID: Identifies the particular QOSM being used by the QNI. It is
assigned by IANA.
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QSPEC Proc.: Is composed of two times 4 bits. The first set of bits
identifies the Message Sequence, the second set
identifies the QSPEC Object Combination used for this
particular message sequence:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|Mes.Sq |Obj.Cmb|
+-+-+-+-+-+-+-+-+
The Message Sequence field can attain the following
values:
0: Sender-Initiated Reservations, as defined in Section
6.1.1
1: Receiver-Initiated Reservations, as defined in
Section 6.1.2
2: Resource Queries, as defined in Section 6.1.3
The Object Combination field can take the values between
1 and 3 indicated in the tables in Section 6.1.1 to
6.1.3.
The QSPEC Control Information is a variable length object containing
one or more parameters. The QSPEC Objects field is a collection of
QSPEC objects (QoS Desired, QoS Available, etc.), which share a
common format and each contain several parameters.
Both the QSPEC Control Information object and the QSPEC QoS objects
share a common header format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|E|r|r| Object Type |r|r|r|r| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
R Flag: If set the parameters contained in the object are read-only.
Otherwise they are read-write. Note that in the case of
Object Type = 0 (Control Information), this value is
overwritten by parameter-specific values.
E Flag: Set if an error occurs on object level
Object Type = 0: control information
= 1: QoS Desired
= 2: QoS Available
= 3: QoS Reserved
= 4: Minimum QoS
The r-flags are reserved.
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Each optional or mandatory parameter within an object can be
similarly encoded in TLV format using a similar parameter header:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|E|N|T| Parameter ID |r|r|r|r| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
M Flag: When set indicates the subsequent parameter is a mandatory
parameter and MUST be interpreted. Otherwise the parameter is
optional and can be ignored if not understood.
E Flag: When set indicates an error occurred when this parameter was
being interpreted.
N Flag: Not-supported Flag (see Section 4.5)
T Flag: Tunneled-parameter Flag (see Section 4.5)
Parameter Type: Assigned to each parameter (see below)
7.2 Parameter Coding
Parameters are usually coded individually, for example, the Bandwidth
Parameter (Section 7.2.2). However, it is also possible to combine
several parameters into one parameter field, which is called
"container coding". This coding is useful if either a) the
parameters always occur together, as for example the several
parameters that jointly make up the token bucket, or b) in order to
make coding more efficient because the length of each parameter value
is much less than a 32-bit word (as for example described in
[RMD-QOSM]).
7.2.1 <NON QOSM Hop> Parameter
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 1 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NON QOSM Hop| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
NON QOSM Hop: This field is set to 1 if a non QOSM-aware QNE is
encountered on the path from the QNI to the QNR. It is a read-write
parameter.
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7.2.2 <Excess Treatment> Parameter
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 2 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Excess Trtmnt| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Excess Treatment: Indicates how the QNE SHOULD process out-of-profile
traffic. The excess treatment parameter is set by the QNI. It is a
read-only parameter. Allowed values are as follows:
0: drop
1: shape
2: remark
3: don't care
7.2.3 <Bandwidth> [RFC 2212, RFC 2215]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 3 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The <Bandwidth> parameter MUST be nonnegative and is measured in
bytes per second and has the same range and suggested representation
as the bucket and peak rates of the <Token Bucket>. <Bandwidth> can
be represented using single-precision IEEE floating point. The
representation MUST be able to express values ranging from 1 byte per
second to 40 terabytes per second. For values of this parameter only
valid non-negative floating point numbers are allowed. Negative
numbers (including "negative zero"), infinities, and NAN's are not
allowed.
A QNE MAY export a local value of zero for this parameter. A network
element or application receiving a composed value of zero for this
parameter MUST assume that the actual bandwidth available is unknown.
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7.2.4 <Slack Term> Parameter [RFC 2212, RFC 2215]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 4 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Slack Term [S] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Slack term S MUST be nonnegative and is measured in microseconds.
The Slack term, S, can be represented as a 32-bit integer. Its value
can range from 0 to (2**32)-1 microseconds.
7.2.5 <Token Bucket> Parameters [RFC 2215]
The <Token Bucket> parameters are represented by three floating
point numbers in single-precision IEEE floating point format followed
by two 32-bit integers in network byte order. The first floating
point value is the rate (r), the second floating point value is the
bucket size (b), the third floating point is the peak rate (p), the
first integer is the minimum policed unit (m), and the second integer
is the maximum datagram size (MTU).
Note that the two sets of <Token Bucket> parameters can be
distinguished, as could be needed for example to support DiffServ
applications (see Section 7.2).
Token Bucket #1 Parameter ID = 5
Token Bucket #1: Mandatory QSPEC Parameter
Parameter Values:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 5 |r|r|r|r| 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Rate [r] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Size [b] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate [p] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Policed Unit [m] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Packet Size [MTU] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Token Bucket #2 Parameter ID = 6
Token Bucket #2: Optional QSPEC Parameter
Parameter Values:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 6 |r|r|r|r| 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Rate [r] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Token Bucket Size [b] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate [p] (32-bit IEEE floating point number) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum Policed Unit [m] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Packet Size [MTU] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
When r, b, p, and R terms are represented as IEEE floating point
values, the sign bit MUST be zero (all values MUST be non-negative).
Exponents less than 127 (i.e., 0) are prohibited. Exponents greater
than 162 (i.e., positive 35) are discouraged, except for specifying a
peak rate of infinity. Infinity is represented with an exponent of
all ones (255) and a sign bit and mantissa of all zeroes.
7.2.6 <QoS Class> Parameters
7.2.6.1 <PHB Class> Parameter [RFC 3140]
As prescribed in RFC 3140, 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 7 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP |0 0 0 0 0 0 0 0 0 0| Reserved |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
The registries needed to use RFC 3140 already exist, see [DSCP-
REGISTRY, PHBID-CODES-REGISTRY]. Hence, no new registry needs to be
created for this purpose.
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7.2.6.2 <Y.1541 QoS Class> Parameter [Y.1541]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 8 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|Y.1541 QoS Cls.| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Y.1541 QoS Class: Indicates the Y.1541 QoS Class. Values currently
allowed are 0, 1, 2, 3, 4, 5.
Class 0:
Mean delay <= 100 ms, delay variation <= 50 ms, loss ratio <= 10^-3.
Real-time, highly interactive applications, sensitive to jitter.
Application examples include VoIP, Video Teleconference.
Class 1:
Mean delay <= 400 ms, delay variation <= 50 ms, loss ratio <= 10^-3.
Real-time, interactive applications, sensitive to jitter.
Application examples include VoIP, Video Teleconference.
Class 2:
Mean delay <= 100 ms, delay variation unspecified, loss ratio <=
10^-3. Highly interactive transaction data. Application examples
include signaling.
Class 3:
Mean delay <= 400 ms, delay variation unspecified, loss ratio <=
10^-3. Interactive transaction data. Application examples include
signaling.
Class 4:
Mean delay <= 1 sec, delay variation unspecified, loss ratio <=
10^-3. Low Loss Only applications. Application examples include
short transactions, bulk data, video streaming.
Class 5:
Mean delay unspecified, delay variation unspecified, loss ratio
unspecified. Unspecified applications. Application examples include
traditional applications of default IP networks.
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7.2.6.3 <DSTE Class Type> Parameter [RFC3564]
DSTE class type is defined as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 9 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|DSTE Cls. Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
DSTE Class Type: Indicates the DSTE class type. Values currently
allowed are 0, 1, 2, 3, 4, 5, 6, 7.
7.2.7 Priority Parameters
7.2.7.1 <Preemption Priority> & <Defending Priority> Parameters
[RFC 3181]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 10 |r|r|r|r| 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preemption Priority | Defending Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Preemption Priority: The priority of the new flow compared with the
defending priority of previously admitted flows. Higher values
represent higher priority.
Defending Priority: 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.
As specified in [RFC3181], <Preemption Priority> and <Defending
Priority> are 16-bit integer values and both MUST be populated if the
parameter is used.
7.2.7.2 <Reservation Priority> Parameter [PRIORITY-RQMTS, SIP-PRIORITY]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|E|N|T| 11 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ Admission | RPH Namespace | RPH Priority |
+ Priority | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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High priority flows, normal priority flows, and best-effort priority
flows can have access to resources depending on their admission
priority value, as described in [PRIORITY-RQMTS], as follows:
Admission Priority:
0 - high priority flow
1 - normal priority flow
2 - best-effort priority flow
[SIP-PRIORITY] defines a resource priority header (RPH) with
parameters "RPH Namespace" and "RPH Priority" combination,
and if populated is applicable only to flows with high reservation
priority, as follows:
RPH Namespace:
0 - dsn
1 - drsn
2 - q735
3 - ets
4 - wps
5 - not populated
RPH Priority:
Each namespace has a finite list of relative priority-values. Each
is listed here in the order of lowest priority to highest priority:
4 - dsn.routine
3 - dsn.priority
2 - dsn.immediate
1 - dsn.flash
0 - dsn.flash-override
5 - drsn.routine
4 - drsn.priority
3 - drsn.immediate
2 - drsn.flash
1 - drsn.flash-override
0 - drsn.flash-override-override
4 - q735.4
3 - q735.3
2 - q735.2
1 - q735.1
0 - q735.0
4 - ets.4
3 - ets.3
2 - ets.2
1 - ets.1
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0 - ets.0
4 - wps.4
3 - wps.3
2 - wps.2
1 - wps.1
0 - wps.0
Note that SIP nodes can send multiple NameSpace.Priority tupple
values in the same message, in part because end nodes may not know
what Namespace "domain" it resides in, nor which Namespace "domains"
it may traverse. Therefore multiple <Reservation Priority>
parameters MAY be sent in a given QSPEC, which is turn contain
multiple RPH Namespace/Priority combinations.
Note that additional work is needed to communicate these flow
priority values to bearer-level network elements
[VERTICAL-INTERFACE].
7.2.8 <Path Latency> Parameter [RFC 2210, 2215]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 12 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Path Latency (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Path Latency is a single 32-bit integer in network byte order.
The composition rule for the <Path Latency> parameter is summation
with a clamp of (2**32 - 1) on the maximum value. The latencies are
average values reported in units of one microsecond. A system with
resolution less than one microsecond MUST set unused digits to zero.
An individual QNE can advertise a latency value between 1 and 2**28
(somewhat over two minutes) and the total latency added across all
QNEs can range as high as (2**32)-2. If the sum of the different
elements delays exceeds (2**32)-2, the end-to-end advertised delay
SHOULD be reported as indeterminate. A QNE that cannot accurately
predict the latency of packets it is processing MUST raise the
not-supported flagand either leave the value of Path Latency as is,
or add its best estimate of its lower bound. A raised not-supported
flagflag indicates the value of Path Latency is a lower bound of the
real Path Latency. The distinguished value (2**32)-1 is taken to
mean indeterminate latency because the composition function limits
the composed sum to this value, it indicates the range of the
composition calculation was exceeded.
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7.2.9 <Path Jitter> Parameter
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 13 |r|r|r|r| 3 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Path Jitter STAT1 (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Jitter STAT2 (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path Jitter STAT3 (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Path Jitter is a set of three 32-bit integers in network byte
order. The Path Jitter parameter is the combination of three
statistics describing the Jitter distribution with a clamp of
(2**32 - 1) on the maximum of each value. The jitter STATs are
reported in units of one microsecond. A system with resolution less
than one microsecond MUST set unused digits to zero. An individual
QNE can advertise jitter values between 1 and 2**28 (somewhat over
two minutes) and the total jitter computed across all QNEs can range
as high as (2**32)-2. If the combination of the different element
values exceeds (2**32)-2, the end-to-end advertised jitter SHOULD be
reported as indeterminate. A QNE that cannot accurately predict the
jitter of packets it is processing MUST raise the not-supported flag
and either leave the value of Path Jitter as is, or add its best
estimate of its STAT values. A raised not-supported flag indicates
the value of Path Jitter is a lower bound of the real Path Jitter.
The distinguished value (2**32)-1 is taken to mean indeterminate
jitter. A QNE that cannot accurately predict the jitter of packets
it is processing SHOULD set its local parameter to this value.
Because the composition function limits the total to this value,
receipt of this value at a network element or application indicates
that the true path jitter is not known. This MAY happen because one
or more network elements could not supply a value, or because the
range of the composition calculation was exceeded.
NOTE: The Jitter composition function and the statistics to use are a
subject of active development in IETF IPPM WG and ITU-T SG 12.
Resolution of this topic is expected shortly.
7.2.10 <Path PLR> Parameter
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 14 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Path Packet Loss Ratio (32-bit floating point) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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The Path PLR is a single 32-bit single precision IEEE floating point
number in network byte order. The composition rule for the <Path
PLR> parameter is summation with a clamp of 10^-1 on the maximum
value. The PLRs are reported in units of 10^-11. A system with
resolution less than one microsecond MUST set unused digits to zero.
An individual QNE can advertise a PLR value between zero and 10^-2
and the total PLR added across all QNEs can range as high as 10^-1.
If the sum of the different elements values exceeds 10^-1, the
end-to-end advertised PLR SHOULD be reported as indeterminate. A QNE
that cannot accurately predict the PLR of packets it is processing
MUST raise the not-supported flag and either leave the value of Path
PLR as is, or add its best estimate of its lower bound. A raised
not-supported flag indicates the value of Path PLR is a lower bound
of the real Path PLR. The distinguished value 10^-1 is taken to mean
indeterminate PLR. A QNE which cannot accurately predict the PLR of
packets it is processing SHOULD set its local parameter to this
value. Because the composition function limits the composed sum to
this value, receipt of this value at a network element or application
indicates that the true path PLR is not known. This MAY happen
because one or more network elements could not supply a value, or
because the range of the composition calculation was exceeded.
7.2.11 <Path PER> Parameter
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 15 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Path Packet Error Ratio (32-bit floating point) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Path PER is a single 32-bit single precision IEEE floating point
number in network byte order. The composition rule for the <Path
PER> parameter is summation with a clamp of 10^-1 on the maximum
value. The PERs are reported in units of 10^-11. A system with
resolution less than one microsecond MUST set unused digits to zero.
An individual QNE can advertise a PER value between zero and 10^-2
and the total PER added across all QNEs can range as high as 10^-1.
If the sum of the different elements values exceeds 10^-1, the
end-to-end advertised PER SHOULD be reported as indeterminate. A QNE
that cannot accurately predict the PER of packets it is processing
MUST raise the not-supported flag and either leave the value of Path
PER as is, or add its best estimate of its lower bound. A raised
not-supported flag indicates the value of Path PER is a lower bound
of the real Path PER. The distinguished value 10^-1 is taken to mean
indeterminate PER. A QNE which cannot accurately predict the PER of
packets it is processing SHOULD set its local parameter to this
value. Because the composition function limits the composed sum to
this value, receipt of this value at a network element or application
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indicates that the true path PER is not known. This MAY happen
because one or more network elements could not supply a value, or
because the range of the composition calculation was exceeded.
7.2.12 <Ctot> <Dtot> <Csum> <Dsum> Parameters [RFC 2210, 2212, 2215]
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 16 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| End-to-end composed value for C [Ctot] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 17 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| End-to-end composed value for D [Dtot] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 18 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Since-last-reshaping point composed C [Csum] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|E|N|T| 19 |r|r|r|r| 1 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Since-last-reshaping point composed D [Dsum] (32-bit integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The error term C is measured in units of bytes. An individual QNE
can advertise a C value between 1 and 2**28 (a little over 250
megabytes) and the total added over all QNEs can range as high as
(2**32)-1. Should the sum of the different QNEs delay exceed
(2**32)-1, the end-to-end error term MUST be set to (2**32)-1. The
error term D is measured in units of one microsecond. An individual
QNE can advertise a delay value between 1 and 2**28 (somewhat over
two minutes) and the total delay added over all QNEs can range as
high as (2**32)-1. Should the sum of the different QNEs delay
exceed (2**32)-1, the end-to-end delay MUST be set to (2**32)-1.
Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 35]
Internet Draft QoS-NSLP QSPEC Template October 2005
8. Security Considerations
The priority parameter raises possibilities for Theft of Service
Attacks because users could claim an emergency priority for their
flows without real need, thereby effectively preventing serious
emergency calls to get through. Several options exist for countering
such attacks, for example
- only some user groups (e.g. the police) are authorized to set the
emergency priority bit
- any user is authorized to employ the emergency priority bit for
particular destination addresses (e.g. police)
9. IANA Considerations
This section provides guidance to the Internet Assigned Numbers
Authority (IANA) regarding registration of values related to the
QSPEC template, in accordance with BCP 26 RFC 2434 [RFC2434].
[QoS-SIG] requires IANA to create a new registry for QoS Signaling
Model Identifiers. The QoS Signaling Model Identifier (QOSM ID) is
a 4 byte value carried in a QSPEC. The allocation policy for
new QOSM IDs is TBD.
This document also defines 4 objects and 20 parameters for the QSPEC
Template, as detailed in Section 7. Values are to be assigned for
them from the NTLP Object Type registry.
10. Acknowledgements
The authors would like to thank (in alphabetical order) David Black,
Anna Charny, Xiaoming Fu, Robert Hancock, Chris Lang, Dave Oran, Tom
Phelan, Hannes Tschofenig, and Sven van den Bosch, for their very
helpful suggestions.
11. Normative References
[DSCP-REGISTRY] http://www.iana.org/assignments/dscp-registry
[PHBID-CODES-REGISTRY] http://www.iana.org/assignments/phbid-codes
[GIST] Schulzrinne, H., Hancock, R., "GIST: General Internet
Signaling Transport," work in progress.
[QoS-SIG] S. Van den Bosch et. al., "NSLP for Quality-of-Service
Signaling," work in progress.
[RFC1832] Srinivasan, R., "XDR: External Data Representation
Standard," RFC 1832, August 1995.
[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.
Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 36]
Internet Draft QoS-NSLP QSPEC Template October 2005
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.
[RFC2211] Wroclawski, J., "Specification of the Controlled-Load
Network Element Service", RFC 2211, Sept. 1997.
[RFC2212} Shenker, S., et. al., "Specification of Guaranteed Quality
of Service," September 1997.
[RFC2215] Shenker, S., Wroclawski, J., "General Characterization
Parameters for Integrated Service Network Elements", RFC 2215, Sept.
1997.
[RFC2474] Nichols, K., et. al., "Definition of the Differentiated
Services Field (DS Field) in the IPv4 and IPv6 Headers," RFC 2474,
December 1998.
[RFC2475] Blake, S., et. al., "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC2597] Heinanen, J., et. al., "Assured Forwarding PHB Group," RFC
2597, June 1999.
[RFC2697] Heinanen, J., Guerin, R., "A Single Rate Three Color
Marker," RFC 2697, September 1999.
[RFC2698] Heinanen, J., Guerin, R., "A Two Rate Three Color Marker,"
RFC 2698, September 1999.
[RFC3140] Black, D., et. al., "Per Hop Behavior Identification
Codes," June 2001.
[RFC3297]Charny, A., et. al., "Supplemental Information for the New
Definition of the EF PHB (Expedited Forwarding Per-Hop Behavior),"
RFC 3297, March 2002.
12. Informative References
[CMSS] "PacketCable (TM) CMS to CMS Signaling Specification,
PKT-SP-CMSS-103-040402, April 2004.
[DIFFSERV-CLASS] Baker, F., et. al., "Configuration Guidelines
for DiffServ Service Classes," work in progress.
[IEEE754] Institute of Electrical and Electronics Engineers, "IEEE
Standard for Binary Floating-Point Arithmetic," ANSI/IEEE Standard
754-1985, August 1985.
[INTSERV-QOSM] Kappler, C., "A QoS Model for Signaling IntServ
Controlled-Load Service with NSIS," work in progress.
[METWORK-BYTE-ORDER] Wikipedia, "Endianness,"
http://en.wikipedia.org/wiki/Endianness.
[PRIORITY-RQMTS] Tarapore, P., et. al., "User Plane Priority Levels
for IP Networks and Services," T1A1/2003-196 R3, November 2004.
[Q.2630] ITU-T Recommendation Q.2630.3: "AAL Type 2 Signaling
Protocol - Capability Set 3" Sep. 2003
[RFC1633] Braden, B., et. al., "Integrated Services in the Internet
Architecture: an Overview," RFC 1633, June 1994.
[RFC3393] Demichelis, C., Chimento, P., "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM), RFC 3393, November 2002.
[RFC3564] Le Faucheur, F., et. al., Requirements for Support of
Differentiated Services-aware MPLS Traffic Engineering, RFC 3564,
July 2003
Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 37]
Internet Draft QoS-NSLP QSPEC Template October 2005
[RFC3726] Brunner, M., et. al., "Requirements for Signaling
Protocols", RFC 3726, April 2004.
[RMD-QOSM] Bader, A., et. al., " RMD-QOSM: An NSIS QoS Signaling
Policy Model for Networks
Using Resource Management in DiffServ (RMD)," work in progress.
[SIP-PRIORITY] Schulzrinne, H., Polk, J., "Communications Resource
Priority for the Session Initiation Protocol(SIP)." work in
progress.
[VERTICAL-INTERFACE] Dolly, M., Tarapore, P., Sayers, S., "Discussion
on Associating of Control Signaling Messages with Media Priority
Levels," T1S1.7 & PRQC, October 2004.
[Y.1540] ITU-T Recommendation Y.1540, "Internet Protocol Data
Communication Service - IP Packet Transfer and Availability
Performance Parameters," December 2002.
[Y.1541] ITU-T Recommendation Y.1541, "Network Performance Objectives
for IP-Based Services," May 2002.
[Y.1541-QOSM] Ash, J., et. al., "Y.1541-QOSM -- Y.1541 QoS Model for
Networks Using Y.1541 QoS Classes," work in progress.
13. Authors' Addresses
Jerry Ash (Editor)
AT&T
Room MT D5-2A01
200 Laurel Avenue
Middletown, NJ 07748, USA
Phone: +1-(732)-420-4578
Fax: +1-(732)-368-8659
Email: gash@att.com
Attila Bader (Editor)
Traffic Lab
Ericsson Research
Ericsson Hungary Ltd.
Laborc u. 1 H-1037
Budapest Hungary
Email: Attila.Bader@ericsson.com
Cornelia Kappler (Editor)
Siemens AG
Siemensdamm 62
Berlin 13627
Germany
Email: cornelia.kappler@siemens.com
Chuck Dvorak
AT&T
Room 2A37
180 Park Avenue, Building 2
Florham Park, NJ 07932
Phone: + 1 973-236-6700
Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 38]
Internet Draft QoS-NSLP QSPEC Template October 2005
Fax:+1 973-236-7453
Email: cdvorak@att.com
Yacine El Mghazli
Alcatel
Route de Nozay
91460 Marcoussis cedex
FRANCE
Phone: +33 1 69 63 41 87
Email: yacine.el_mghazli@alcatel.fr
Georgios Karagiannis
University of Twente
P.O. BOX 217
7500 AE Enschede
The Netherlands
Email: g.karagiannis@ewi.utwente.nl
Andrew McDonald
Siemens/Roke Manor Research
Roke Manor Research Ltd.
Romsey, Hants SO51 0ZN
UK
Email: andrew.mcdonald@roke.co.uk
Al Morton
AT&T
Room D3-3C06
200 S. Laurel Avenue
Middletown, NJ 07748
Phone: + 1 732 420-1571
Fax: +.1 732 368-1192
Email: acmorton@att.com
Percy Tarapore
AT&T
Room D1-33
200 S. Laurel Avenue
Middletown, NJ 07748
Phone: + 1 732 420-4172
Email: tarapore@.att.com
Lars Westberg
Ericsson Research
Torshamnsgatan 23
SE-164 80 Stockholm, Sweden
Email: Lars.Westberg@ericsson.com
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Appendix A: QoS Models and QSPECs
This Appendix gives a description of QoS Models and QSPECs and
explains what is the relation between them. Once these descriptions
are contained in a stable form in the appropriate IDs this Appendix
will be removed.
QoS NSLP is a generic QoS signaling protocol that can signal for many
QOSMs. A QOSM is a particular QoS provisioning method or QoS
architecture such as IntServ Controlled Load or Guaranteed Service,
DiffServ, or RMD for DiffServ.
The definition of the QOSM is independent from the definition of QoS
NSLP. Existing QOSMs do not specify how to use QoS NSLP to signal
for them. Therefore, we need to define the QOSM specific signaling
functions, as [RMD-QOSM], [INTSERV-QOSM], and [Y.1541-QOSM].
A QOSM SHOULD include the following information:
- Role of QNEs in this QOSM:
E.g. location, frequency, statefulness...
- QSPEC Definition:
A QOSM SHOULD specify the QSPEC, including QSPEC parameters.
Furthermore it needs to explain how QSPEC parameters not used in this
QOSM are mapped onto parameters defined therein.
- Message Format
QSPEC objects to be carried in RESERVE, QUERY RESPONSE and NOTIFY
- State Management
It describes how QSPEC info is treated and interpreted in the
RMF and QOSM specific processing. E.g.
admission control, scheduling, policy control, QoS parameter
accumulation (e.g. delay).
- Operation and Sequence of Events
Usage of QoS-NSLP messages to signal the QOSM.
Appendix B: Mapping of QoS Desired, QoS Available and QoS Reserved of
NSIS onto AdSpec, TSpec and RSpec of RSVP IntServ
The union of QoS Desired, QoS Available and QoS Reserved can provide
all functionality of the objects specified in RSVP IntServ, however
it is difficult to provide an exact mapping.
In RSVP, the Sender TSpec specifies the traffic an application is
going to send (e.g. token bucket). The AdSpec can collect path
characteristics (e.g. delay). Both are issued by the sender. The
receiver sends the FlowSpec which includes a Receiver TSpec
describing the resources reserved using the same parameters as the
Sender TSpec, as well as a RSpec which provides additional IntServ
QoS Model specific parameters, e.g. Rate and Slack.
The RSVP TSpec/AdSpec/RSpec seem quite tailored to receiver-initiated
Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 40]
Internet Draft QoS-NSLP QSPEC Template October 2005
signaling employed by RSVP, and the IntServ QoS Model. E.g. to the
knowledge of the authors it is not possible for the sender to specify
a desired maximum delay except implicitly and mutably by seeding the
AdSpec accordingly. Likewise, the RSpec is only meaningfully sent in
the receiver-issued RSVP RESERVE message. For this reason our
discussion at this point leads us to a slightly different mapping of
necessary functionality to objects, which should result in more
flexible signaling models.
Appendix C: Main Changes Since Last Version & Open Issues
C.1 Main Changes Since Version -04
Version -05:
- fixed <QOSM hops> in Sec. 5 and 6.2 as discussed at Interim Meeting
- discarded QSPEC parameter <M> (Maximum packet size) since MTU
discovery is expected to be handled by procedure currently defined
by PMTUD WG
- added "container QSPEC parameter" in Sec. 6.1 to augment encoding
efficiency
- added the 'tunneled QSPEC parameter flag' to Sections 5 and 6
- revised Section 6.2.2 on SIP priorities
- added QSPEC procedures for "RSVP-style reservation", resource
queries and bidirectional reservations in Sec. 7.1
- reworked Section 7.2
Version -06:
- defined "not-supported flag" and "tunneled parameter flag"
(subsumes "optional parameter flag")
- defined "error flag" for error handling
- coding checked by independent expert
- coding of QSPEC Procedure ID
C.2 Open Issues
- none
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Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 41]
Internet Draft QoS-NSLP QSPEC Template October 2005
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Ash, et. al. <draft-ietf-nsis-qspec-06.txt> [Page 42]
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