Overview of Quality
of Service (QoS)
APT-ITU workshop on the International
Telecommunications Regulations
Bangkok, 6-8 February 2012
Richard Hill, ITU
Content
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Introduction
Global Challenges
The ITU’s past and current Work on QoS
Other International Agreements
Proposals made on this topic
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Introduction
• Quality of Service (QoS)
– The totality of characteristics of a telecommunications service
that bear on its ability to satisfy stated and implied needs of the
user of the service
– Characteristics can be measured by objective means
• level meter
• delay counter
• etc.
– Often confused with Network Performance (NP)
• IETF uses QoS to describe the performance of functional
services in network layer models
• QoS often more precisely named as "end-to-end QoS"
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Introduction
• User
Perception
influenced by
much more:
trends
advertising
tariffs,
costs
customer expectation of QoS
customer satisfaction
QoS
(technical)
Network
Performance
Terminal
Performance
QoS
(non-technical)
Point of Sale
Customer
Care
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Introduction
• User Perception of quality not limited to the objective
characteristics at the man-machine interface
• For end users counts the quality that they personally
experience during their use of a telecommunication service
• Quality of Experience (QoE) takes into account additional
subjective parameters
– stemming from user expectations
– from the context, in which the user is embedded during
the use of the service, such as
• personal mood
• environment
– potential discrepancy between the service offered and
individual users reading additional features into the
service
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Content
•
•
•
•
•
Introduction
Global Challenges
The ITU’s past and current Work on QoS
Other International Agreements
Proposals made on this topic
6
Global Challenges
• Move from traditional networks
– based on dedicated service-channels
• Towards on a single packet based transport infrastructure
– With integrated (transport) services
• Pre-defined transmission planning of QoS has become a major
challenge:
– Fixed allocation of resources is no longer possible
– Packet-based network quality parameter requirements are
pretty undefined
– Responsibility for end-to-end QoS has been lost
– Services must be considered as applications executed in the
terminal devices
– IP networks cannot provide for self standing end-to-end QoS
 Only transport classes, which enable QoS differentiation
• QoS Challenges depend strongly on role of stakeholders
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1) Challenges for Network Equipment
Manufacturers
• Rely on the QoS related performance requests (of network and
system functions) from network operators and service providers
• Ideally, network equipment manufacturers would participate in
the QoS work of SDOs
– To standardize the QoS and performance requirements
between several parties involved in the network business
– Often no visible incentive on the short term
– Return of investment cannot easily be seen
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2) Challenges for Terminal Device
Manufacturers
• Confronted with a mass market
• Move away from minimum attachment requirements
– No harm to the network, not necessarily high QoS
• Towards terminal standards which target the possibility of provision
of high-level end-to-end QoS to the customer
• Acceptance in the market based on other factors
– Price
– Other functions of terminals
– Applications available for that terminal
– Brand
– End-to-end QoS - not in the first place
– "kids prefer the pink phone!"
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3) Challenges for Network Operators and
Service Providers
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•
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Huge investments in both infrastructure and access technology, likely to partially
– Investing in new capacity, and
– Rationing existing capacity
Traffic management tools
– Increase efficiency of managing existing network capacity
Appropriateness of different approaches to traffic management is at the heart of
the Net Neutrality debate
– Important to bear in mind that traffic management has always beneficial
aspects
– Commonly used to protect safety-critical traffic
– Question is not whether traffic management is acceptable in principle, but
whether particular approaches to traffic management cause concern
– Network operators and service providers may or may not use traffic
management as a welcome method towards suppressing competition
– Opening access and core packet networks as pure bit pipes will probably not
provide the envisaged revenues
– Therefore network operators and service providers are aiming at providing
services on top of the bit stream itself
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4) Challenges for Regulators and
Administrations
•
Responsibility to consumer protection affected by rapid introduction of
vendor-specific new services
– Also required to set a right balance between service competition
and infrastructure competition
– In the early days of the move towards end-to-end services being
no longer provided on a fixed, well-known platform, it still seemed
to be fairly easy to require that the new technology provide QoS
"not less than in the ISDN era"
– Today it is easy to lose the overview of proprietary services "onnet" and the respectively offered QoS
– Services are not standardized
– For interconnection scenarios (one of the major responsibilities of
the ITU, and one of the main purposes of the ITRs) one would
need specific service agreements for each network-to-networkinterface (NNI).
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•
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In contrast, Regulators and Administrations have seen in the recent
past that the un-managed Internet has led to the creation of new
services offered "over the top"
– Important factor contributing to the economical benefits
Regulators and Administrations to have a close look
– Conditions under which access to services in comparison to the
access to the Internet is being provided
– There may be a certain percentage of the bandwidth or of the
capacity reserved for the on-net services which then are not
available for the access to the Internet
5) Challenges for Customers
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Personal affairs of using telecommunication services
– Discrepancy between advertised and actual delivery speeds of
the network
Consumers may not be able to detect the actual applications of
discriminating traffic management techniques and find it difficult to
distinguish between the effects of traffic management techniques on
QoS from the effects of other quality degrading factors
– A consumer observing that traffic is routinely throttled may not
know whether this is done by intention, or is caused by other
factors
– Traffic management techniques and policies are difficult to
understand for consumers
 Consumers may find it difficult to act upon such information
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... in Technical Terms
• Dramatic increase in mobile communication, both in terms of the
number of registered devices and of the volume of requested
resources makes it is quite likely that migration scenarios and
hybrid connections with existing wire-bound and traditional
networks and terminals will be neglected and appropriate QoS
standards will not be established or enforced
– Main technical parameters to consider will be:
– speed (data throughput) of the access network
– congestion in the backbone
– end-to-end delay (latency)
– delay-variation (jitter)
– packet loss (loss of information) -to-end QoS
• Jitter is the variation in delay between different packets
– Compensation (by de-jitter buffers) converts jitter into
additional delay
• Packet loss may be concealed
– Essential information may be lost
• Bad terminal implementations may destroy reasonable
performance delivered from the network(s)
– Users will not be able to judge the difference in end-to-end
QoS
Current Policy Challenges
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Need to consider new approaches to anchor national strategies or regulatory
frameworks around the multi-facetted concept of QoS required
- To set and keep the right balance between service and infrastructure
competitions
- To address the challenges associated with QoS on the telecommunication
network
To continue providing adequate QoS, network operators and service providers
claim to need a certain traffic management over increasingly congested
networks
- This might include data restrictions, traffic throttling, filtering and/or the
use of data caps of thresholds
- Once the cap is exceeded, customers or end-users may be, knowingly or
not, confronted with the fact that, "Internet access" provided to them is no
longer Internet access, but a service provided by their ISP;
- Such possible circumstances have influenced debates over ‘net neutrality’
and ‘differentiated traffic management’
- These issues are increasingly likely to come to the fore, if data traffic
continues to grow at its current projected rate
- Currently, many regulators are launching public consultations and
investigations into traffic throttling practices
•
To continue providing adequate QoS, network operators and service
providers claim to need a certain traffic management over
increasingly congested networks
– This might include data restrictions, traffic throttling, filtering
and/or the use of data caps of thresholds
– Once the cap is exceeded, customers or end-users may be,
knowingly or not, confronted with the fact that, "Internet access"
provided to them is no longer Internet access, but a service
provided by their ISP;
– Such possible circumstances have influenced debates over ‘net
neutrality’ and ‘differentiated traffic management’
 These issues are increasingly likely to come to the fore, if data
traffic continues to grow at its current projected rate
 Currently, many regulators are launching public consultations
and investigations into traffic throttling practices
• Best Practice Guidelines for Enabling Open Access from ITU’s Global
Symposium for Regulators (GSR) in 2010
– Recommend that only objectively justifiable differentiations be
made in the way in which various data streams are treated
– The Guidelines stress the importance of legislation to set out the
general principles of open access: non-discrimination,
effectiveness and transparency.
• The European Commission (EC) policy on net neutrality published in
April 2011, The Open Internet and Net Neutrality in Europe
– calls for greater disclosure of traffic management practices
– recognizes that traffic management is necessary to ensure the
smooth flow of Internet traffic
• One of the key policy questions regarding network neutrality
regulation is,
– whether to ban optional business-to-business transactions
between broadband ISPs and content providers or application
providers for enhanced QoS in the delivery of “their” packets
over the network
• The discussions have significant economic and financial aspects
– Affect who pays for what with respect to delivery of the
network infrastructure and content.
– This in turn affects how future infrastructure will be financed
and rolled out.
– Much of the traffic growth is coming from video
– Some fixed-line operators have been seeking for a way to
implement differentiated pricing in order to increase their
revenues
• In the European Union, discussions are taking place to one degree or
another regarding the following:
1) The ability of consumers to address all legal content on the
Internet.
2) Transparency, in the sense of clear information on services and
prices.
3) Non-discrimination, in the sense of not prioritizing certain
content or applications in harmful ways.
4) Traffic management, in the sense of intervening in the flow of
traffic, for example to optimize bandwidth or to eliminate
spam.
5) Differentiation, in the sense of allowing customers to choose
service offers that differ with respect to characteristics such as
price and speed.
Status of Net Neutrality Initiatives in
selected Countries
Stage in process
Position along the spectrum
(least to most stringent)
Country
No consultation
Considered net neutrality, but found no
problems requiring a consultation and
subsequent rule; will continue to monitor
Denmark
Germany
Ireland
Portugal
Non-binding neutrality guidelines
Norway
In consultation stage
Rules/legislation
adopted
Information gathering on current practices to Italy
potentially establish rules
Transparency/disclosure rules proposed, but
no traffic management
United Kingdom
Transparency/disclosure rules and traffic
management/non-discrimination rules
proposed
Brazil
Sweden
Transparency/disclosure rules but no traffic
management/non-discrimination rules
European Commission
Transparency/disclosure rules and traffic
management/non-discrimination rules
Canada
Chile
France
Netherlands
United States
Content
•
•
•
•
•
Introduction
Global Challenges
The ITU’s past and current Work on QoS
Other International Agreements
Proposals made on this topic
2
The ITU’s past and current Work on QoS
• The ITU has a long-standing history of QoS Work
– Starting as early as 1957 the ITU has been conducting expert
work in the fields of transmission planning, subjective testing
and standards for telephone sets.
– Since 1986 the Speech Quality Experts Group (SQEG) provided
coordination of the quality requirements and subjective testing
methodologies for speech coding algorithms
– Since 1997 the Video Quality Experts Group (VQEG) provides
coordination of the quality requirements and subjective testing
methodologies for video coding algorithms
• Today, in the ITU-T, Study Group 12 is the Lead Study Group on
Performance, Quality of Service (QoS) and Quality of Experience
(QoE)
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The ITU’s past and current Work on QoS
• There are approximately 175 Recommendations, 7 Supplements
and 3 Handbooks on QoS published by the ITU and in force.
• Recently, a free download of ITU-T Test Signals for
Telecommunication Systems was provided.
• POLQA (Perceptual Objective Listening Quality Assessment) as per
new Rec. ITU-T P.863 is the most sophisticated tool the ITU ever
published for assessment of a QoS parameter "by objective
means“. Listening Quality can be "measured" with excellent
accuracy, e.g. during mobile network drive-by testing.
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The ITU’s past and current Work on QoS
• Rec. ITU-T Y.1541 (Network performance objectives for IP-based
services) provides technical parameters for the differentiation of
IP network traffic classes, encompassed by a huge number of
appendices explaining application scenarios and background.
• Rec. Y.1542 (Framework for achieving end-to-end IP performance
objectives) considers various approaches toward achieving endto-end (UNI-UNI) IP network performance objectives.
• The ITU GSR10 Best Practice Guidelines for Enabling Open Access
have been developed (available at www.itu.int/ITUD/treg/bestpractices.html ).
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Challenges for Standards Developing
Organizations (SDOs)
• Standards Developing Organizations (SDOs), like ITU-T, The
European Telecommunications Standards Institute (ETSI), or The
Internet Engineering Task Force (IETF);
– Have collective knowledge and expertise with respect to QoS
 related to the change of paradigms in networks and
terminals
 regarding to planning and possible regulation of end-to-end
QoS
• However, SDOs are seeing increasing cases where stakeholders
decided to rely on industry standards instead of globally recognized
standards
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Content
•
•
•
•
•
Introduction
Global Challenges
The ITU’s past and current Work on QoS
Other International Agreements
Proposals made on this topic
2
Other International Agreements
• No significant internationally binding agreements on endto-end QoS outside the ITU
– Specification work takes place in some industry fora
– ETSI Technical Committee "Speech and multimedia Transmission
Quality" (STQ)
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Terminals and networks for speech and media quality
End-to-end single multimedia transmission performance
QoS parameters for networks and services
QoE descriptors and methods
Content
•
•
•
•
•
Introduction
Global Challenges
The ITU’s past and current Work on QoS
Other International Agreements
Proposals made on this topic
2
Proposals made on this topic
• Many proposals in recent years
– Technical aspects of management of QoE
– In various forums, including ETSI
• Most of these items have been on the table in ITU-T Study Group 12
– Work is contribution-driven,
– Questionable whether new standards will be established
• Other kind of approach comes from regulators
– Seeking balance between
 the protection of the rights of consumers and
 excessively rigid regulation
– Ofcom in the UK have proposed "easy-to-understand" labelling
• as illustrated on the next slides
Elements for "easy-to-understand" labelling
Illustrative QoE Summary for 3 hypothetical ISPs
Illustrative transparent traffic
management status representations
Proposals made on this topic
• Regarding the so-called “net-neutrality” debate, some proposals
presented to CWG-WCIT may touch upon some of these topics.
• For example,
•
- Member States shall ensure transparency with respect to retail and
wholesale prices, costs, and quality of service.
- Member States shall take measures to ensure that an adequate return is
provided on investments in network infrastructures. If this cannot be
achieved through market mechanisms, then other mechanisms may be
used.
- Member States shall [take measures to] ensure that fair compensation is
received for carried traffic (e.g. interconnection or termination).
Regulatory measures may be imposed to the extent that this cannot be
achieved through market mechanisms.
However, there is no consensus regarding such proposals
•
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It should be noted that the ITRs contain provisions regarding the right to communicate,
a topic which is sometimes discussed in the context of “Net Neutrality”.
- Art.3.4 of ITRs states “Subject to national law, any user, by having access to the
international network established by an administration (or recognized private
operating agency), has the right to send traffic. A satisfactory quality of service
should be maintained to the greatest extent practicable, corresponding to relevant
CCITT Recommendations”.
- Proposals have been made to revise this provision, for example, to state that
“Member States recognize the right of the public to correspond by means of the
international service of public correspondence.”
It should be noted that Art.34 of ITU Constitution provides that Member States reserve
the right to cut off, in accordance with their national law, any private
telecommunications which may appear dangerous to the security of the State or
contrary to its laws, to public order or to decency.
Thank you
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