TSVWG R. Geib, Ed.
Internet-Draft Deutsche Telekom
Intended status: Informational February 14, 2014
Expires: August 18, 2014
DiffServ interconnection classes and practice
draft-geib-tsvwg-diffserv-intercon-05
Abstract
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.
Status of this Memo
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This Internet-Draft will expire on August 18, 2014.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Related work . . . . . . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Aggregating PHBs of a class by a DSCP Precedence Prefix . . . 6
4. An Interconnection class and codepoint scheme . . . . . . . . 6
4.1. Treatment of Network Control traffic at carrier
interconnection interfaces . . . . . . . . . . . . . . . . 9
5. DiffServ Intercon relation to other QoS standards . . . . . . 10
5.1. MPLS, Ethernet and DSCP Precedence Prefixes for
aggregated classes . . . . . . . . . . . . . . . . . . . . 11
5.2. Proposed GSMA IR.34 to DiffServ Intercon mapping . . . . . 11
5.3. Proposed MEF 23.1 to DiffServ Intercon mapping . . . . . . 12
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . 16
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
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 feature [RFC2475]. 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.
IP precedence has been deprecated. MPLS and Ethernet support 3 bit
code point fields to differentiate service quality (see MPLS TC /
Traffic Class [RFC5462] and PCP, Priority Code Point [IEEE802.1Q]).
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.
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.
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
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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.
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:
o There should be a coding reserve for interconnection classes.
This leaves space for future standards, for private bilateral
agreements and for provider internal classes.
o 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 (see e.g. [RFC5129]).
o Migrations from one code point scheme to another may require spare
QoS code points.
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.
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.
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:
o the basic concept of this draft is to maintain classes, while
expecting DSCP remarking at provider edges.
o This draft follows RFC4594 in the proposed marking of provider
Network Control traffic and expands RFC4594 on treatment of CS6
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marked traffic at interconnection points (see section 5.2).
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.
1.1. Related work
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
classes [RFC5160]. 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
BGP [I-D.knoll-idr-cos-interconnect], [ID.idr-sla] 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.
2. Terminology
This draft re-uses existing terminology.
DSCP Precedence Prefix Bits 0-2 of the DSCP ("x" in this generic
DSCP: xxxddd) are called the DSCP Precedence Prefix. Section
4.2 of [RFC2474] 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".
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.
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3. Aggregating PHBs of a class by a DSCP Precedence Prefix
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.
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.
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.
RFC 2474 specifies the Class Selector Codepoints [RFC2474]. 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.
4. An Interconnection class and codepoint scheme
Interconnecting parties face the problem of matching classes to be
interconnected and then to agree on code point mapping. As stated by
the DiffServ Architecture [RFC2475], 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.
This draft picks up the DiffServ interconnection class defintions
proposed by ITU-T Y.1566 [Y.1566]. In addition to the classes
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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:
Class Priority: PHB EF, DSCP 101 110. The figures of merit
describing the PHB to be in the range of low single digit
milliseconds. See [RFC3246]. 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).
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.
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.
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.
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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.
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|
+++++++++
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| DiffServ
+----------+
|AF31, AF32|
+----------+
| Intercon
+++++++++
|RtrPrHF|
+++++++++
|
+----------+
|AF31, AF21|
+----------+
|
Provider-F
GSM IR.34
DiffServ Intercon example
Figure 1
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.
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.
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.
4.1. Treatment of Network Control traffic at carrier interconnection
interfaces
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.
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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.
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).
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:
o classification of traffic which is network control traffic for
both domains. This traffic should be classified and marked for
the NC PHB.
o 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.
o any other CS6 marked traffic should be remarked or dropped.
5. DiffServ Intercon relation to other QoS standards
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
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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.
5.1. MPLS, Ethernet and DSCP Precedence Prefixes for aggregated classes
The interconnection class and code point scheme respects properties
and limits of a 3 bit PHB coding space in different ways:
o it allows to classify four interconnection classes based on the
DSCP Precedence Prefix.
o 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.
o 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).
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).
5.2. Proposed GSMA IR.34 to DiffServ Intercon mapping
GSMA IR.34 provides guidelines on how to set up and interconnect
Internet Protocol (IP) Packet eXchange (IPX) Networks [IR.34]. 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
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Backbone.
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.
| 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 |
+---------------+-------+--------------+--------+
Suggested mapping of GSMA IR.34 classes and PHBs to DiffServ Intercon
Figure 2
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.
5.3. Proposed MEF 23.1 to DiffServ Intercon mapping
MEF 23.1 is an implemenation agreement facilitating Ethernet service
interoperability and consistency between Operators and the use of a
common CoS Label set for Subscribers [MEF23.1]. 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
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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.
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):
| MEF 23.1 | DiffServ-Intercon |
| | |
| Agg. Class | PHB | Agg. Class | PHB |
+---------------+-------+--------------+--------+
| High | EF | Priority | EF |
+---------------+-------+--------------+--------+
| Medium | AF3 |Bulk inelastic| AF41 |
+---------------+-------+--------------+--------+
| Low | CS1 | Default | CS0 |
+---------------+-------+--------------+--------+
Suggested mapping of MEF 23.1 color blind mode classes and PHBs to
DiffServ Intercon
Figure 3
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.
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6. Contributors
David Black provided many helpful comments and inputs to this work.
7. Acknowledgements
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.
8. IANA Considerations
This memo includes no request to IANA.
9. Security Considerations
This document does not introduce new features, it describes how to
use existing ones. The security section of RFC 2475 [RFC2475] and
RFC 4594 [RFC4594] apply.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, June 1999.
[RFC3246] Davie, B., Charny, A., Bennet, J., Benson, K., Le Boudec,
J., Courtney, W., Davari, S., Firoiu, V., and D.
Stiliadis, "An Expedited Forwarding PHB (Per-Hop
Behavior)", RFC 3246, March 2002.
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[RFC3260] Grossman, D., "New Terminology and Clarifications for
Diffserv", RFC 3260, April 2002.
[RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
Protocol Label Switching (MPLS) Support of Differentiated
Services", RFC 3270, May 2002.
[RFC5129] Davie, B., Briscoe, B., and J. Tay, "Explicit Congestion
Marking in MPLS", RFC 5129, January 2008.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, February 2009.
[min_ref] authSurName, authInitials., "Minimal Reference", 2006.
10.2. Informative References
[I-D.knoll-idr-cos-interconnect]
Knoll, T., "BGP Class of Service Interconnection",
draft-knoll-idr-cos-interconnect-11 (work in progress),
November 2013.
[ID.idr-sla]
IETF, "Inter-domain SLA Exchange", IETF, http://
datatracker.ietf.org/doc/draft-ietf-idr-sla-exchange/,
2013.
[IEEE802.1Q]
IEEE, "IEEE Standard for Local and Metropolitan Area
Networks - Virtual Bridged Local Area Networks", 2005.
[IR.34] GSMA Association, "IR.34 Inter-Service Provider IP
Backbone Guidelines Version 7.0", GSMA, GSMA IR.34 http:/
/www.gsma.com/newsroom/wp-content/uploads/2012/03/
ir.34.pdf, 2012.
[MEF23.1] MEF, "Implementation Agreement MEF 23.1 Carrier Ethernet
Class of Service Phase 2", MEF, MEF23.1 http://
metroethernetforum.org/PDF_Documents/
technical-specifications/MEF_23.1.pdf, 2012.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594,
August 2006.
[RFC5127] Chan, K., Babiarz, J., and F. Baker, "Aggregation of
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Internet-Draft Abbreviated Title February 2014
Diffserv Service Classes", RFC 5127, February 2008.
[RFC5160] Levis, P. and M. Boucadair, "Considerations of Provider-
to-Provider Agreements for Internet-Scale Quality of
Service (QoS)", RFC 5160, March 2008.
[Y.1566] ITU-T, "Quality of service mapping and interconnection
between Ethernet, IP and multiprotocol label switching
networks", ITU,
http://www.itu.int/rec/T-REC-Y.1566-201207-I/en, 2012.
Appendix A. Change log
00 to 01 Added terminology and references. Added details and
information to interconnection class and codepoint scheme.
Editorial changes.
01 to 02 Added some references regarding related work. Clarified
class definitions. Further editorial improvements.
02 to 03 Consistent terminology. Discussion of Network Management
PHB at interconnection interfaces. Editorial review.
03 to 04 Again improved terminology. Better wording of Network
Control PHB at interconnection interfaces.
Author's Address
Ruediger Geib (editor)
Deutsche Telekom
Heinrich Hertz Str. 3-7
Darmstadt, 64295
Germany
Phone: +49 6151 5812747
Email: Ruediger.Geib@telekom.de
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