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Introduction
� ITU-T Rec. E. 800 defines QoS as “collective effect of service
performance which determines the degree of satisfaction of a user
of the service”
� ITU-T Recommendation P.10/G.100, defines Quality of Experience
(QoE) as, “the overall acceptability of an application or service, as
perceived subjectively by the end-user”
� QoE includes complete end-to-end system effects (client, terminal,
network and service infrastructure)
� Overall acceptability may be influenced by user expectations and
context.
Why the need for good QoS/QoE?
� For the development of telecommunications products and services acceptable to the industry and users/consumers
� Making interconnected networks work seamlessly well together (inter-operability)
� Ensure consumers get value for money
� Mobile has become de facto means of communications in Africa
� Signal Availability (QoS/QoE) on mobile networks is essential for economic and social survival in Africa
� Necessary for effective e-communications such as e-government, e-money transfer
� Ensure fulfillment of universal access
� Encourage fair competition-good quality (and not necessarily price) will guarantee customer retention
ITU-T QoS Perspective
ITU-T Recommendation E.800 has four (4) QoS view
points namely:
� Customer's QoS requirements;
� Service Provider's offerings of QoS (or
planned/targeted QoS);
� QoS achieved or delivered;
� Customer Survey ratings of received QoS.
The closer the 4 view points are in a given
service, the better the QoS delivered.
ITU-T Four Views QoS Perspective
Customer Service Provider
Achieved or
delivered QoS
Customer
received QoS
Customer's QoS
requirementsService Provider's
offerings of QoS
QoS Parameters
� Are also called; metrics, indicators, measures, determinants
� Are premised on indicators such as: speed, accuracy,
availability, reliability, security, simplicity, satisfaction
� Characterize the QoS level of the service being offered to the
satisfaction of the user
� Ensure the users of a services are getting QoS levels matching
what they are paying for
� Used in development and implementation of SLA
� Can be classified as; objective-measurements of physical
attributes of a circuit, system, network etc or subjective-
conducting of customer opinion surveys
QoS Targets
� Also called; objectives, benchmarks,
thresholds, minimum standards, reference
values etc
� A potential value (or range of values) to be
achieved to ensure satisfaction with service
delivery
� Used to maintain good QoS levels based on
international, local or benchmarked standards
� Used to improve QoS levels following
consumer complaints
Telecoms Services QoS Targets
Fixed Telephony:
� Service Supply Time
� Fault Report Rate
� Fault Repair Time
� Call Success Rate
� Call Set-up Time
� Response time for operator service (call centers)
� Response time for directory enquiry service
� Billing accuracy
� Billing Complaints Resolution time
� Call Connection Delay
� Ratio of working payphones
Mobile Telephony Service
No significant difference with fixed telephony
parameters:
� Service Supply Time
� Fault Report Rate
� Fault Repair Rate
� Call Center Answer Time
� Billing and Tariff Accuracy
� Completed Calls
� Dropped Calls
� Blocked Calls
� Speech Quality (MOS, PESQ)
Telecoms Services QoS Targets
Mobile Telephony (contd)
� SMS Message Transmission Success Rate
� Call Set-up Time
� Handover Success Rate
� Geographic Coverage
� Received Signal Strength (RxLv)
� Received Signal Quality (Rx Qual)
Telecoms Services QoS Targets
Data Networks and Internet QoS parameters-cannot be
isolated from the fixed or mobile telephony parameters
due to convergence of technologies. IP packets are used in
both fixed
and mobile services.
� Bandwidth
� Latency
� BER
� Jitter and Jitter Variations
� Throughput
� Data Transmission Success Rate
� Internet Session Login Success Rate
Telecoms Services QoS Targets
QoS Measurement Method
� Objective- circuits attributes, networks, signals
� Subjective-through customer satisfaction surveys
� Subjective good- fits the QoS definition but time
consuming
� Therefore a mix of the two methods recommended
Enforcing Compliance
�Regulators monitor, measure and enforce operators’
obligations
�Obligations normally in licenses or regulations
�Enforcements sometimes entails consultations
�Regulator needs techniques to ensure compliance
even after consultation
Enforcing Compliance (Contd)
Some of the enforcement methods are:
� Publication of QoS measurement results
� Reprimands
� Directives
� Imposition of Penalties
� Requiring operators/service providers compensate their customers
� Imposition of embargos to persistent violators (no Gvt Contracts)
� License Revocation-as a last resort
� Encourage Self Regulation-
Enforcing Compliance (Contd)
Service Level Agreements (SLA)
� Signed between service providers or between service providers and their customers
� Define service characteristics, responsibilities and priorities between parties
� May include statements on specific performance, billing, QoS levels etc
� May also include remedies for breach
� Regulator needs to enforce SLA where parties fail to do so
International Standards Developing Organizations (SDOs)
� Besides ITU-T, other international telecommunications
standardization development organizations (SDOs)exist
� ISO, ETSI, IETF, INTUG, TM Forum, etc
� They deal with the general and special telecommunications
quality of service issues.
International Standards Developing Organizations (SDOs)
(Contd.)
� ITU-T organizes its work in study groups subdivided into working parties .
� SG12 is the lead SG in the performance, QoSand QoE.
� One of its affiliates is SG12 RG-AFR
� Most of the ITU-T Recommendations dealing with QoS exist in the E, G, I, M, Q, P, X and Y series.
International Standards Developing Organizations (SDOs)
(Contd.)
ITU-T gathers together
� Governments,
� National telecommunication administrations.
� Recognized operating agencies.
� Manufacturers.
� Service providers.
� Scientific and industrial organizations
� Consumer protection groups
International Standards Developing Organizations (SDOs)
(Contd.)
� In addition, Quality of Services Development Group
(QSDG) is involved in QoS/QoE.
� Its main aim is to improve the quality of international
telecommunication services.
� Its activities were transferred from SG2 to SG12
during the WTSA08 in Johannesburg, South Africa
in 2008.
� Held its last meeting in Maputo, Mozambique
List of ITU-T QoS-related Recommendations and other
international QoS standards
No. Organization Standard Content
1 ITU-T ITU-T Rec. G.109 Definition of
categories of speech
transmission quality
2 ITU-T Rec. G.1010 End-user multimedia
QoS categories
3 ITU-T Rec. G.1000 Communications
quality of service: A
framework and
definitions
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
4 ITU-T Rec. E.800 Terms and
definitions related
to QoS/NP
including
dependability
5 ITU-T Rec. I. 350 General aspects of
quality of service
and network
performance in
digital networks
including ISDN
6 ITU-T Rec. X.641 Information
Technology-QoS
Framework
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
7 ITU-T Rec. G.107 E- Model. A
computational
model for use in
transmission
planning
8 ITU-T Rec. G.1000 Communications
quality of service.
A framework and
Definition
9 ITU-T Rec. E.801 Framework for
service quality
agreement
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
10 ITU-T Rec. E 802 Framework and
methodology for
the determination
and application of
QoS parameters
11 ITU-T Rec. E.860 Framework of
service level
agreement
12 ITU-T Rec. P.
10/G.100
Vocabulary for
performance and
quality of service-
Definition of QoE
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
13 ITU-T Rec. P. 800 Methods for
subjective
determination of
transmission
quality
14 ITU-T Rec. P. 862 Perceptual evaluation
of speech quality
(PESQ). An
objective method
for end-to-end
speech quality
15 ITU-T Rec. Y.1540 IP packet transfer and
availability
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
16 ITU-T Rec. Y. 1541 Network
performance
objectives for IP-
based services
17 ITU-T Rec. Y. 1542 Framework for
achieving end-to-
end IP
Performance
Objectives
18 ITU-T Rec. X.140 QoS parameters for
public data
networks
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
19 ISO EN ISO 9000:2000 Quality management
systems.
Fundamentals and
vocabulary
20 EN ISO 9001:2000 Quality management
systems.
Requirements
21 EN ISO 9004:2000 Quality management
systems. Guidelines
for performance
improvements
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
22 ETSI EG 202 086 Objectives and principles for
"traditional quality"
telephone service
23 EG 201 377-1 Part 1: Introduction to objective
comparison measurement
methods for one-way speech
quality across networks
24 EG 201 377-3 Part 3: Non-intrusive objective
measurement methods
applicable to networks and
links with classes of services
List of ITU-T QoS-related Recommendations and
other international QoS standards (Contd.)
25 EG 201 474 Speech transmission quality across
multiple interconnected networks
26 EG 201 769 QoS parameters of voice telephony
required under ONP Voice
Telephony Directive 98/10/EC
27 EG 202 009-1 Part 1: Methodology for
identification of parameters relevant
to the Users
List of ITU-T QoS-related Recommendations and other international
QoS standards (Contd.)
28 EG 202 009-2 Part 2: User related
parameters on a
service specific
basis
29 EG 202 009-3 Part 3: Template for
Service Level
Agreements
(SLA)
30 EG 202 057-1 User-related QoS
parameter
definitions and
measurements
Part 1: General
List of ITU-T QoS-related Recommendations and other
international QoS standards (Contd.)
31 EG 202 057-2 User-related QoS parameter
definitions and measurements
Part 2: Voice telephony, Group
3 fax and modem data
services
32 EG 202 057-3 User related QoS parameter
definitions and measurements
Part 3: QoS parameters
specific to public land mobile
networks (PLMN)
33 EG 202 057-4 User related QoS parameter
definitions and measurements
Part 4: Internet Access
List of ITU-T QoS-related Recommendations and
other international QoS standards (Contd.)
34 IETF RFC 1633, QoS in intserv
35 RFC 2475 QoS in diffserv
36 RFC 3031 MPLS
37 RSVP 2205-2209 RSVP