One document matched: draft-geib-tsvwg-diffserv-intercon-05.xml
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<rfc category='info' docName='draft-geib-tsvwg-diffserv-intercon-05' ipr='trust200902'>
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<front>
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<title abbrev="Abbreviated Title">DiffServ interconnection classes and practice</title>
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<author fullname="Ruediger Geib" initials="R." role="editor"
surname="Geib">
<organization>Deutsche Telekom</organization>
<address>
<postal>
<street>Heinrich Hertz Str. 3-7</street>
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<code>64295</code>
<city>Darmstadt</city>
<region></region>
<country>Germany</country>
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<phone>+49 6151 5812747</phone>
<email>Ruediger.Geib@telekom.de</email>
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</author>
<date month="February" year="2014" />
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<!-- Meta-data Declarations -->
<area>Transport</area>
<workgroup>TSVWG</workgroup>
<!-- WG name at the upperleft corner of the doc -->
<keyword>DiffServ, Interconnection, QoS, QoS class</keyword>
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<abstract>
<t>This document proposes a limited and well defined set of QoS PHBs
and PHB groups to be applied at (inter)connections of two separately
administered and operated networks. Many network providers operate
Aggregated DiffServ classes. This draft contains DiffServ aggregation
friendly interconnection concepts.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t> DiffServ has been deployed in many networks. As described by section 2.3.4.2
of RFC 2475, remarking of packets at domain boundaries is a DiffServ <xref
target="RFC2475">feature</xref>. This draft proposes a set of standard QoS
classes and code points at interconnection points to which and from which
locally used classes and code points should be mapped. </t>
<t>IP precedence has been deprecated. MPLS and Ethernet support 3 bit code
point fields to differentiate service quality (see <xref target="RFC5462">
MPLS TC / Traffic Class</xref> and
<xref target="IEEE802.1Q">PCP, Priority Code Point</xref>). The concept of classifying DiffServ traffic classes
by the bits 0-2 of a DSCP has been part of Diffserv from start on. This
is also reflected by the DiffServ codepoint definitions of AF and EF.
It is common practice today also to copy these three DSCP bits into
MPLS TC or Ethernet P-Bits. PHBs based on DSCP bit 0-2 classification
may be applied in core network sections rather than then DSCP based PHBs.
Network providers make use of this feature for their own IP QoS concepts.
This draft suggests to expand it to interconnections between operators of
different domains in a simple manner while each operator may maintain
the own class and codepoint scheme within the own domain.</t>
<t>The scope of this draft is limited to 4 specified interconnection classes
having four different 3 bit code points in DSCP bits 0-2. Using more than the 4
proposed IP precedences at interconnection could
result in non-revertible IP Precedence or DSCP rewrites and avoid sustaining
end-to-end QoS classes, if a receiving provider operates more than 4 MPLS TCs.
Assume a provider operating 4 QoS classes available at interconnection and MPLS
within his backbone. Further assume this carrier to support MPLS based ECN
marking and assume this carrier to operate a newtork control class with an own
MPLS TC. Two codepoints are left for future use. If 5 or more PHBs each with
different DSCP bits 0-2 are offerd at an interconnection point and no more than
a single MPLS label needs to be pushed, two (or more) PHBs will carry the same
DSCP bits 0-2 after re-marking to the provider internal QoS scheme. Due to MPLS
pen ultimate hop popping, DSCPs must be re-written in this case. That may work
if bits 3-5 of the DSCP can be varied without introducing ambiguities. Should
this traffic later pass another QoS interconnection point further downstream,
the orginal sending domain may not be able to ensure proper class mapping for
the PHBs merged into a single class by the receiving domain. </t>
<t>At first glance, the interconnection codepoint scheme looks like an
additional effort. But there are some obvious benefits: each party sending or
receiving traffic has to specify the mapping from or to the interconnection
class and code point scheme only once. Without it, this is to be negotiated per
interconnection party individually. Further, end-to-end QoS in terms
of traffic being classified for the same class in all passed domains
is more likely to result if an interconnection code point scheme is used.
It is not necessarily resulting from individual per provider mapping
negotiations, as can be seen from the example given above. </t>
<t>The standards and deployments known to the author of this draft are
limited to 4 DiffServ classes at interconnection points (or
less). The example given in RFC 5127 on aggregation of DiffServ service
classes picks 4 Treatment aggregates (note that this document prefers
class instead of treatment aggregate). Reasons to favour working with 4
DiffServ interconnection classes: </t>
<t> <list style="symbols">
<t>There should be a coding reserve for interconnection classes.
This leaves space for future standards, for private bilateral
agreements and for provider internal classes.</t>
<t>The fields available for carrying QoS information (e.g., DiffServ
PHB) in MPLS and Ethernet are only 3 bits in size, and are intended for
more than just QoS purposes (<xref target="RFC5129">see e.g.</xref>).</t>
<t>Migrations from one code point scheme to another may require spare
QoS code points.</t>
</list> </t>
<t>IP Precedence has been deprecated when DiffServ was standardised. It
is common practice today however to copy the DSCPs Bits 0-2 (called
DSCP Precedence Prefix in the following) into MPLS TC or Ethernet P-Bits.
This is also reflected by the DiffServ codepoint
definitions of AF and EF. Class based PHBs may be applied
in core network sections rather than then DSCP based PHBs.</t>
<t>The set of available router and traffic management tools to configure
and operate DiffServ classes is limited. This should be reflected by
class definitions. These may in the end be more related to transport
properties (e.g., whether the traffic in a class is congestion controlled
or not) than to application requirements. </t>
<t>RFC5127 provides recommendations on domain internal aggregation
of DiffServ traffic and offers a deployment example [RFC5127]. This
draft differs from the RFC5127 aggregation deployment example in the
following points: </t>
<t> <list style="symbols">
<t>the basic concept of this draft is to maintain classes, while expecting
DSCP remarking at provider edges. </t>
<t>This draft follows RFC4594 in the proposed marking of provider Network
Control traffic and expands RFC4594 on treatment of CS6 marked traffic at
interconnection points (see section 5.2). </t>
</list> </t>
<t>The proposed Interconnection class and code point scheme tries to
reflect and consolidate related DiffServ and QoS standardisation
efforts outside of the IETF, namely MEF [MEF 23.1], GSMA [IR.34] and ITU
[Y.1566]. GSMAs IR.34 specifies an inter provider VPN, but it is
nevertheless specifying a kind of DiffServ aware IP based carrier
interconnection.</t>
<section title="Related work">
<t>In addition to the standardisation activities which triggered this work,
other authors published RFCs or drafts which may benefit from an
interconnection class- and codepoint scheme. RFC 5160 suggests Meta-QoS-
Classes to enable deployment of standardised end to end QoS
<xref target="RFC5160">classes</xref>. The authors agree that the proposed
interconnection class- and codepoint scheme as well as the idea of
standardised end to end classes would complement their own work. Work on
signaling Class of Service at interconnection interfaces by
<xref target="I-D.knoll-idr-cos-interconnect">BGP</xref>,
<xref target="ID.idr-sla"> </xref> is beyond the scope of this draft.
Should the basic transport and class properties be standardised as proposed
here, signaled access to QoS classes may be of interest. The current BGP
drafts focus on exchanging SLA and traffic conditioning parameters. They
seem to assume that common interpretation of the PHB properties identified
by DSCPs has been established prior to exchanging further details by BGP
signaling.</t>
</section>
</section>
<section title="Terminology">
<t>This draft re-uses existing terminology.</t>
<t><list hangIndent="8" style="hanging">
<t hangText="DSCP Precedence Prefix"> Bits 0-2 of the DSCP ("x" in this
generic DSCP: xxxddd) are called the DSCP Precedence Prefix.
<xref target="RFC2474">Section 4.2 of </xref> discusses the role of these bits
in enabling use of DiffServ with network equipment that is not fully DiffServ-
compliant; this term provides a formal for these bits that is preferable to
referring to them as "the former IP Precedence field".</t>
<t hangText="DSCP Precedence Class"> This is a set of one or more PHBs
that utilize the same DSCP Precedence Prefix on an interconnection between
two networks.</t>
</list> </t>
</section>
<section title="Aggregating PHBs of a class by a DSCP Precedence Prefix">
<t>Configuration and operation of MPLS networks is simplified, if a DSCP
Precedence Class can be aggregated into a single PSC by classifying them on
their DSCP Precedence Prefix. The DSCP Precedence Prefix of an interconnection
DSCP Precedence Class may be rewritten at the ingress edge router and then
simply be copied into the MPLS TC field of one or more labels to be pushed. </t>
<t>To allow for simple carrier interconnection agreements, carriers
sending traffic belonging to the same class but marked by DSCPs with
differing DSCP Precedence Prefixes should apply the interconnection marking
and code point scheme specified below, if they interconnect to a carrier
applying DSCP Precedence Prefix based traffic aggregation. An example where
this may be applicable is the Interactive Class of GSMA IR.34 [IR.34]).
Another option is to negotiate a customised interconnection agreement
of course. </t>
<t>Classification by DSCP Precedence Prefix is useful for links aggregating
DiffServ traffic. DSCP Precedence Prefix based classification is not
recommended as a general mode of operation. Edge systems, QoS policy
enforcement nodes, service areas and hosts benefit from fine grained DSCP
based classification and should continue to do so.</t>
<t>RFC 2474 specifies the <xref target="RFC2474">Class Selector Codepoints
</xref>. These offer a similar concept, but they are strictly limited to xxx000
DSCPs. The Class Selector Code points don't offer aggregation, they
just simplify classification. This draft intents to aggregate
several PHBs of a single class by a DSCP Precedence Prefix, which a
different concept than that of the Class Selector Code points. </t>
</section>
<section title="An Interconnection class and codepoint scheme">
<t>Interconnecting parties face the problem of matching classes to be
interconnected and then to agree on code point mapping. As stated by
the <xref target="RFC2475">DiffServ Architecture</xref>, remarking is a
standard behaviour at interconnection interfaces. This draft
proposes a standard interconnection set of 4 DSCP precedence classes with
well defined DSCP and DSCP Precedence Prefix values. A sending party
remarks DSCPs from internal schemes to the Interconnection
code points. The receiving party remarks DSCP Precedence Prefixes and
/ or DSCPs to her internal scheme. Thus the interconnection
code point scheme fully complies with the DiffServ architecture. </t>
<t>This draft picks up the DiffServ interconnection class defintions proposed
by ITU-T <xref target="Y.1566"> Y.1566 </xref>. In addition to the classes
defined there, this draft proposes a complete set of PHBs and DSCPs. Like in
the example given by RFC 5127 for domain internal class aggregation, Y.1566
specifies four PHB scheduling classes (for provider interconnection however).
Their properties slightly from those of the RFC5127 example:</t>
<t><list hangIndent="8" style="hanging">
<t hangText="Class Priority:">PHB EF, DSCP 101 110. The figures of merit
describing the PHB to be in the range of low single digit milliseconds.
<xref target="RFC3246">See</xref>. This class corresponds to RFC 5127's
real time class, but it is limited to traffic for which node configuration
"ensures that the service rate of EF packets on a given output interface
exceeds their arrival rate at that interface over long and short time
intervals" (see RFC 3246). </t>
<t hangText="Bulk inelastic:">PHB AF41, DSCP 100 010 (the other AF4 PHB
group PHB's and DSCPs should be reserved for future extension of this DSCP
scheduling class). Optimised for low loss, low delay, low jitter at high
bandwidth. Traffic load in this class must be controlled, e.g. by
application servers. One example could be flow admission control. There may
be infrequent retransmissions requested by the application layer to mitigate
low levels of packet losses. Discard of packets through active queue
management should be avoided in this class. Congestion in this class may
result in bursty packet loss. If used to carry multimedia traffic, it is
recommended to carry audio and video traffic in a single PHB (note that
video conferencing may require separate PHBs for audio and video traffic,
which could also be realised by utlising two AF 4 PHBs). All of these
properties influence the buffer design. This class is designed to transport
those parts of RFC 5127's Real Time class, which consume considerable
QoS bandwidth at the interconnection interface.</t>
<t hangText="Assured:">The complete PHB group AF3, DSCPs 011 010, 011 100
and 011 110.
This class may be optimised to transport traffic without bandwidth
requirements. It aims on very low loss at high bandwidths. Retransmissions
after losses characterise the class and influence the buffer design. Active
queue management with probabilistic dropping may be deployed. The RFC 5127
example calls this class Assured Elastic. </t>
<t hangText="Default:">Default PHB, CS0 with DSCP 000 000. This class may
be optimised to transport traffic without bandwidth requirements.
Retransmissions after losses characterise the class and influence the
buffer design. Active queue management with probabilistic dropping may be
deployed. The RFC 5127 example calls this class Elastic.</t>
</list> </t>
<t> The idea is illustrated by an example. Provider O and provider W are peer
with provider T. They have agreed upon a QoS interconnection. Traffic of
provider O terminates within provider Ts network, while the GSMA IR.34
traffic transits through the netwirk of provider T to provider F. Assume
all providers to run their own internal codepoint schemes for a class with
properties of the DiffServ Intercon Assured class. See section for a
description of GSMA IR.34. </t>
<figure anchor="IntercoN-example">
<preamble></preamble>
<artwork>
Provider-O Provider-W
RFC5127 GSMA 34.1
| |
+----------+ +----------+
|AF21, AF22| |AF31, AF21|
+----------+ +----------+
| |
V V
+++++++++ +++++++++
|Rtr PrO| |Rtr PrW|
+++++++++ +++++++++
| DiffServ |
+----------+ +----------+
|AF31, AF32| |AF31, AF32|
+----------+ +----------+
| Intercon |
V V
+++++++++ |
|RtrPrTI|------------------+
+++++++++
| Provider-T domain
+-----------+
| MPLS TC 2 |
|and rewr. |
|DSCP pref 2|
+-----------+
| | Local DSCPs Provider-T
| | +----------+ +++++++++
V +->|AF21, AF22|->-|RtrDstH|
| +----------+ +++++++++
+----------+
|AF21, AF22|
+----------+
|
+++++++++
|RtrPrTE|
+++++++++
| DiffServ
+----------+
|AF31, AF32|
+----------+
| Intercon
+++++++++
|RtrPrHF|
+++++++++
|
+----------+
|AF31, AF21|
+----------+
|
Provider-F
GSM IR.34
</artwork>
<postamble>DiffServ Intercon example</postamble>
</figure>
<t>It is easily visible that all providers only need to deploy internal DSCP to
DiffServ Intercon DSCP mappings to exchange traffic in the desired classes.
</t>
<t>RFC5127 specifies a separate PHB scheduling class for network control
traffic. This class may be present at interconnection interfaces too, but
depending on the agreement between providers, it may also be classified for
another interconnection class. See section 4.2 for a detailed discussion.
</t>
<t>The proposed class and code point scheme is designed for point to
point IP layer interconnections. Other types of interconnections are
out of scope of this document. The basic class and code point scheme
is applicable on Ethernet layer too. </t>
<section title="Treatment of Network Control traffic at carrier interconnection interfaces">
<t>As specified by RFC4594, section 3.2, Network Control (NC) traffic
marked by CS6 is to be expected at interconnection interfaces. This
document does not change NC specifications of RFC4594. The latter
specification is detailed on domain internal NC traffic and on
traffic exchanged between peering points. Further, it recommends not
to forward CS6 marked traffic originating from user-controlled end
points by the NC class of a provider domain.</t>
<t>As a minor clarification to RFC4594, "peering" shouldn't be
interpreted in a commercial sense. The NC PHB is applicable also in
the case of a purchased network service based on a transit agreement
with an upstream provider. RFC4594 recommendations on NC traffic are
applicable for IP carrier interconnections in general.</t>
<t>Some CS6 traffic exchanged accross carrier interconnections will
terminate at the domain ingress node (e.g., if BGP is running between
the two routers on opposite ends of the interconnection link).</t>
<t>An IP carrier may limit access to the NC PHB for traffic which is
recognised as network control traffic relevant to the own domain.
Interconnecting carriers should specify treatment of CS6 marked
traffic received at a carrier interconnection which is to be
forwarded beyond the ingress node. An SLA covering the following
cases is recommended, if a carrier wishes to send CS6 marked
traffic accross an interconnection link which isn't terminating
at the interconnected ingress node:</t>
<t><list style="symbols">
<t>classification of traffic which is network control traffic for
both domains. This traffic should be classified and marked for the
NC PHB.</t>
<t>classification of traffic which is network control traffic for the
sending domain only. This traffic should be classified for a PHB
offering similar properties as the NC class (e.g. AF31 as
specified by this document). As an example GSMA IR.34 proposes an Interactive
class / AF31 to carry SIP and DIAMETER traffic. While this is service control
traffic of high importance to the interconnected Mobile Network Operators, it is
certainly no Network Control traffic for a fixed network providing transit. The
example may not be perfect. It was picked nevertheless because it refers to an
existing standard.</t>
<t>any other CS6 marked traffic should be remarked or dropped.</t>
</list></t>
</section>
</section>
<section title="DiffServ Intercon relation to other QoS standards">
<t> This sections provides suggestions how to aggregate traffic by DSCP
Precedence Prefexies to Ethernet and MPLS. Other Standardisation Organsiations
deal with QoS aware provider interconnection. As IP is the state of the art
realisation of provider interconnections, these standards bodies specify
DiffServ aware interconnections. Some of these bodies are industry alliances
chartered also to promote interconnection of wireless or Ethernet technology
including the exchange of IP datagrams at interconnection points. Examples are
the Metro Ethernet Forum (MEF) or the GSM Alliance (GSMA). The ITU was mentioned
earlier. ITU works across and between responsibilities of different
Standardisation Organisations and liaising with them, if their responsibilities
are touched, is traditional part of that process. </t>
<section title="MPLS, Ethernet and DSCP Precedence Prefixes for aggregated classes">
<t> The interconnection class and code point scheme respects properties
and limits of a 3 bit PHB coding space in different ways:</t>
<t><list style="symbols">
<t>it allows to classify four interconnection classes based on the DSCP
Precedence Prefix. </t>
<t>it supports a single PHB group (AF3), whose DSCPs may be aggregated into
a sinle MPLS TC (or Ethernet priority) based on their joint DSCP Precedence
Prefix. This kind of aggregation will work for the AF4 PHB group, if the
PHBs AF42 and AF43 need to be supported in addition to AF41. </t>
<t>Applying only 4 aggregated classes at interconnection allows for
bilateral extensions, if desired. Should two carriers agree to map AF32
and AF33 to an additional individual MPLS TC and offer an Ordered
Aggregate across the interconnecting domain, this proposal at leaves
some MPLS TC coding space for such an extension (although this draft
doesn't recommend interconnections of that type).</t>
</list> </t>
<t> The above statement is no requirement to depricate any DSCP to MPLS
TC or Ethernet P-Bit mapping functionality. In the opposite, by
limiting the interconnection scheme to 6 PHBs, each PHB may be mapped
to an individual Traffic Class or Priority also within MPLS or Ethernet
(if desired). </t>
</section>
<section title="Proposed GSMA IR.34 to DiffServ Intercon mapping">
<t>GSMA IR.34 provides guidelines on how to set up and interconnect <xref target="IR.34">
Internet Protocol (IP) Packet eXchange (IPX) Networks</xref>. An IPX network is an
inter-Service Provider IP backbone which comprises the interconnected networks of IPX
Providers. IPX is a telecommunications interconnection model for the exchange of IP based
traffic between customers of separate mobile and fixed operators as well as other types
of service provider (such as ISP), via IP based network-to-network interface. Note that IPX
is not a public interconnection model however, it is designed as a private IP Backbone
of the interconnected parties. Two IPX partners may interconnect using transit offered by an
Inter-Service Provider IP Backbone. This requires an IP QoS aware interconnection as described
by this draft between IPX provider and Inter-Service Provider IP Backbone.</t>
<t> GSMA IR.34 specifies 4 aggregated classes and 7 PHBs. Mapping to DiffServ Intercon is smooth
apart from the GSMA aggregated class Interactive, which consistfs of 4 PHBs. The table below
lists a suggested mapping to DiffServ Intercon.</t>
<figure anchor="IR.34_mapping">
<preamble></preamble>
<artwork>
| GSMA IR.34 | DiffServ-Intercon |
| | |
| Agg. Class | PHB | Agg. Class | PHB |
+---------------+-------+--------------+--------+
|Conversational | EF | Priority | EF |
+---------------+-------+--------------+--------+
| Streaming | AF41 |Bulk inelastic| AF41 |
+---------------+-------+--------------+--------+
| Interactive | AF31 | Assured | AF31 |
+ +-------+ +--------+
| (ordered by | AF32 | | |
+ priority, +-------+ + AF32 +
| AF3 highest) | AF21 | | |
+ +-------+ +--------+
| | AF11 | | AF33 |
+---------------+-------+--------------+--------+
| Background | CS0 | Default | CS0 |
+---------------+-------+--------------+--------+
</artwork>
<postamble>Suggested mapping of GSMA IR.34 classes and PHBs to DiffServ Intercon</postamble>
</figure>
<t> The motivation resulting in the design of the IR.34 Intercative class are unknown to the author of this draft. It is out of scope of this draft to decide how 4 PHBs can be mapped to a to single aggregated class. The suggested mapping is pragmatic and tries to come as close as possible to other design criteria pursued by GSMA IR.34. </t>
</section>
<section title="Proposed MEF 23.1 to DiffServ Intercon mapping">
<t> MEF 23.1 is an implemenation agreement facilitating Ethernet service
interoperability and consistency between Operators and the use of a <xref target="MEF23.1"> common CoS Label set for Subscribers </xref>. It pursues the same aims and method on Ethernet layer as this draft does on IP layer (i.e. providing an interconnection class and codepoint scheme). MEF 23.1 addresses external network to network interfaces typically interconnecting metro ethernet providers. This may typically involve Ethernet Network Sections associated with typical Operator domains that interconnect at external network to network interfaces. MEF 23.1 specifies three aggregated CoS classes. In addition, the usage of a subset of Ethernet PCP and IP DSCP values is specifiedthus facilitating synergies between Ethernet and IP services and networks. The main purpose is specifying operator virtual (Ethernet) connections. As an IP QoS model is added, this draft proposes an IP class and codepoint mapping. </t>
<t> MEF 23.1 QoS mapping requires some thought as 3 classes are supported of which two are Ordered Aggregates. MEF 23.1s section 8.5.1 example on IP DSCP mapping may suggest supporting classification based on the DSCP Precedence Prefix. MEF 23.1 section 8.5.2.1 allows the conclusion that MEF class M is best mapped to this drafts Bulk inelastic class. The suggested mapping MEF to DiffServ Intercon is limited to the the MEF color blind mode (3 classes, no sub-classes): </t>
<figure anchor="MEF_23.1_mapping">
<preamble></preamble>
<artwork>
| MEF 23.1 | DiffServ-Intercon |
| | |
| Agg. Class | PHB | Agg. Class | PHB |
+---------------+-------+--------------+--------+
| High | EF | Priority | EF |
+---------------+-------+--------------+--------+
| Medium | AF3 |Bulk inelastic| AF41 |
+---------------+-------+--------------+--------+
| Low | CS1 | Default | CS0 |
+---------------+-------+--------------+--------+
</artwork>
<postamble>Suggested mapping of MEF 23.1 color blind mode classes and PHBs to DiffServ Intercon</postamble>
</figure>
<t> The MEF color aware mode supports Ordered Aggregates in the MEF classes M and L. The MEF L specification classifies AF1 and Best Effort for the same Ordered Aggregate. A Better than Best Effort service produced in the same queue as best effort traffic can be realized, but hasn't been standardized by IETF. This document doesn't suggest any mapping. Diffserv Intercon also doesn't suggest an Ordered Aggregate in the Bulk Inelastic class. Later versions of this document may do so and specify a solution. Both issues are left for bilateral negotiation. </t>
</section>
</section>
<section title="Contributors">
<t>David Black provided many helpful comments and inputs to this work.</t>
</section>
<section title="Acknowledgements">
<t> Al Morton and Sebastien Jobert provided feedback on many aspects during
private discussions. Brian Carpenter, Mohamed Boucadair and Thomas Knoll helped
adding awareness of related work.</t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This memo includes no request to IANA.</t>
</section>
<section anchor="Security" title="Security Considerations">
<t> This document does not introduce new features, it
describes how to use existing ones. The security section of
<xref target="RFC2475">RFC 2475</xref> and
<xref target="RFC4594">RFC 4594</xref> apply. </t>
</section>
</middle>
<!-- *****BACK MATTER ***** -->
<back>
<!-- References split into informative and normative -->
<!-- There are 2 ways to insert reference entries from the citation libraries:
1. define an ENTITY at the top, and use "ampersand character"RFC2629; here (as shown)
2. simply use a PI "less than character"?rfc include="reference.RFC.2119.xml"?> here
(for I-Ds: include="reference.I-D.narten-iana-considerations-rfc2434bis.xml")
Both are cited textually in the same manner: by using xref elements.
If you use the PI option, xml2rfc will, by default, try to find included files in the same
directory as the including file. You can also define the XML_LIBRARY environment variable
with a value containing a set of directories to search. These can be either in the local
filing system or remote ones accessed by http (http://domain/dir/... ).-->
<references title="Normative References">
<!--?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"?-->
<?rfc include='reference.RFC.2474'?>
<?rfc include='reference.RFC.2475'?>
<?rfc include='reference.RFC.2597'?>
<?rfc include='reference.RFC.3246'?>
<?rfc include='reference.RFC.3260'?>
<?rfc include='reference.RFC.3270'?>
<?rfc include='reference.RFC.2119'?>
<?rfc include='reference.RFC.5129'?>
<?rfc include='reference.RFC.5462'?>
<reference anchor="min_ref">
<!-- the following is the minimum to make xml2rfc happy -->
<front>
<title>Minimal Reference</title>
<author initials="authInitials" surname="authSurName">
<organization></organization>
</author>
<date year="2006" />
</front>
</reference>
</references>
<references title="Informative References">
<!-- Here we use entities that we defined at the beginning. -->
<?rfc include='reference.RFC.5160'?>
<?rfc include='reference.RFC.5127'?>
<?rfc include='reference.RFC.4594'?>
<?rfc include='reference.I-D.knoll-idr-cos-interconnect'?>
<!-- A reference written by by an organization not a person. -->
<reference anchor="ID.idr-sla">
<front>
<title>Inter-domain SLA Exchange
</title>
<author>
<organization>IETF</organization>
</author>
<date year="2013"/>
</front>
<seriesInfo name="IETF, " value="http://datatracker.ietf.org/doc/draft-ietf-idr-sla-exchange/"/>
</reference>
<reference anchor="IEEE802.1Q">
<front>
<title>IEEE Standard for Local and Metropolitan Area Networks - Virtual Bridged Local Area Networks
</title>
<author>
<organization>IEEE</organization>
</author>
<date year="2005" />
</front>
</reference>
<reference anchor="IR.34">
<front>
<title>IR.34 Inter-Service Provider IP Backbone Guidelines Version 7.0
</title>
<author>
<organization>GSMA Association</organization>
</author>
<date year="2012" />
</front>
<seriesInfo name="GSMA, " value="GSMA IR.34 http://www.gsma.com/newsroom/wp-content/uploads/2012/03/ir.34.pdf"/>
</reference>
<reference anchor="MEF23.1">
<front>
<title>Implementation Agreement MEF 23.1 Carrier Ethernet Class of Service Phase 2
</title>
<author>
<organization>MEF</organization>
</author>
<date year="2012"/>
</front>
<seriesInfo name="MEF, " value="MEF23.1 http://metroethernetforum.org/PDF_Documents/technical-specifications/MEF_23.1.pdf"/>
</reference>
<reference anchor="Y.1566">
<front>
<title>Quality of service mapping and interconnection between Ethernet, IP and multiprotocol label switching networks
</title>
<author>
<organization>ITU-T</organization>
</author>
<date year="2012"/>
</front>
<seriesInfo name="ITU, " value="http://www.itu.int/rec/T-REC-Y.1566-201207-I/en"/>
</reference>
</references>
<section anchor="app-additional" title="Change log">
<t><list hangIndent="8" style="hanging">
<t hangText="00 to 01">Added terminology and references. Added details and
information to interconnection class and codepoint scheme. Editorial changes.</t>
<t hangText="01 to 02">Added some references regarding related work.
Clarified class definitions. Further editorial improvements.</t>
<t hangText="02 to 03">Consistent terminology. Discussion of Network Management
PHB at interconnection interfaces. Editorial review.</t>
<t hangText="03 to 04">Again improved terminology. Better wording of Network
Control PHB at interconnection interfaces.</t>
</list></t>
</section>
<!-- Change Log
v00 2012-10-26 RG Initial version
v01 2013-02-20 RG Added material see change log and editorial changes
v02 2013-02-25 RG Added some references promised for -01 but forgotten there
v03 2013-06-14 RG Clarified Traffic Class definition and Network Management treatment and some other issues.
v04 2013-10-18 RG Clarified DSCP Precedence Prefix specification and Network Control treatment.
-->
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 01:34:00 |