Quality of Service (QoS) - Universitas Indonesiastaff.ui.ac.id/system/files/users/ir.muhammad/material/sistel11qos.pdf · QoS Parameters Bandwidth – rate of flow of multimedia data

Slide 1Muhamad Asvial

http://www.ee.ui.ac.id/~cicer

Quality of Service (QoS)



PerfectionPerfection

Fusing the Best Properties of Today’s Networks onto a Common Lowest Cost

Infrastructure

Mobility of the Mobility of the GSM NetworkGSM Network

Ubiquity/ReliabilitUbiquity/Reliability of the PSTNy of the PSTN

Bandwidth Bandwidth of an of an

Optical Optical NetworkNetwork

Latency Latency Control of an Control of an ATM NetworkATM Network

Operational Operational Ease of EthernetEase of Ethernet

Flexibility of Flexibility of the Internetthe Internet

Security of Security of Financial Financial

Funds Funds TransfersTransfers

Characteristics of the Ideal Network



Mobility of the GSM NetworkMobility of the GSM Network

Ubiquity/Reliability of the PSTN

Ubiquity/Reliability of the PSTN

Bandwidth of an

Optical Network

Bandwidth of an

Optical Network

Latency Control of an ATM Network

Latency Control of an ATM Network

Operational Ease

of Ethernet

Operational Ease

of Ethernet

Flexibility of the InternetFlexibility of the Internet

Content Richness of Cable/TelevisionContent Richness

of Cable/Television

Security of aPrivate

Network

Security of aPrivate

Network

Fusing The Best Properties of Today’s Networks



QoS Definition

EQoS = EUROSCOM QoSEUROSCOM (European Institute for Research and Strategic

Studies in Telecommunications)

the degree of conformance of the service delivered to a user by a provider with an agreement between them (EQoS)



QoS: IETF Version

• In its broadest sense, QoS refers to “the ability to ensure the quality of the end user (human) experience”

• This can encompass a huge range of technological and other aspects– Multimedia coding and quality measurement– SLA definition and performance verification– Application behaviour to select QoS– High performance physical and link layers– Packet delivery (primary IETF focus)



QoS: ITU – T Version

• Real QoS is end-to-end, as the user sees it• QoS and its various performance aspects are core

competencies of the ITU-T• There are many QoS activities in the ITU-T



QoS: Users' concerns

• Today, any technical body in any standardization organization refers to users' QoS requirements.

• Each of these TBs has different purposes:– means to improve the technical QoS– measurement methods of the QoS– definition of QoS service classes

• All of them have in mind the technical quality• Few of them are taking into account the users'

concerns about the QoS



QoS: Users' concerns• Service fields

– Provision– Operation– Customer services– Billing– Other services

• Market areas– Voice– Data– Internet access– Private/public networks



Users' QoS criteria (1/4)

• Provision– Preliminary information – Completion efficiency – Respect of allotted time– Contract clarity– Contract flexibility




• Operation– Service availability– Coverage (mobile networks)– Unsuccessful call ratio– Set-up swiftness – Absence of dropouts– Speech or data quality– Flow rate or transactions time– Exchange security – Terminal protection




• Customer services– Swiftness of after-sales service to answer calls– Swiftness to repair– Availability of operator services– Efficiency of help line– Number of call to report fault.




• Billing– Accuracy (counting and tariff)– Number of claims

• Other services – Directory service availability

• Response time • Relevance of the answers



Lacks in current standards (1/5)

• Provision– Preliminary information – Completion efficiency– Respect of allotted time– Contract clarity– Contract flexibility




• Operation– Service availability– Coverage (mobile networks)– Unsuccessful call ratio– Set-up swiftness – Absence of dropouts– Speech or data quality– Flow rate or transactions time– Exchange security – Terminal protection




• Customer services– Swiftness of after-sales service to answer calls– Swiftness to repair– Availability of operator services– Efficiency of help line– Number of call to report fault.




• Billing– Accuracy (counting and tariff)– Number of claims

• Other services – Directory service availability

• Response time• Relevance of the answers



The Challenge: User’s Perspective

How to better take into account the users' concerns about

QoS regulation and standardizationand how to fill the current gaps



QoS Objectives

It’s important to satisfy customer expectations for end-to-end Quality of Service and Reliability

for all types of transactions and services

Performance Parameters

Delay & JitterErrored Packets

Packet LossThroughput

Priority, Restoration

SLAsService Level Agreements

ReliabilityAdequate

Service AvailabilityOver a Specific Period of Time



Service Level Agreement



Conceptual Model



Sample QoS Parameters



QoS Parameters

Bandwidth– rate of flow of multimedia data

Latency– time required for the end-to-end transmission of a single

data elementJitter

• variation in latency

Loss rate– the proportion of data elements that can be dropped or

delivered late

*



QoS in GPRS (1/4)

• Only “Best Effort” for GPRS (no bit rate guaranteed, no delay guaranteed, etc)

• No notion of “connection” in the Access Network => the flows from all users are “mixed” => Impossibility to guarantee any QoS



AccessNetwork

GPRS Core

Network

Terminals

Gb interface

Distinction between flows from different users impossible at

transport level on Gb

“Connections” are known by the CN and the Terminals

QoS in GPRS (2/4) : CN/AN interface in GPRS



QoS in GPRS (3/4)

• However, QoS parameters are defined to prioritise the individual incoming packets and to specify if retransmissions are impossible and/or requested



QoS in GPRS (4/4)

Name Value Delay class From 1 (short

delay) to 4 (background)

Reliability class From 1 (<= 10-5) to 5 (> 5*10-4)

Peak throughput class From 1 (< 16 kbit/s) to 9 (>= 2 Mbit/s)

Precedence class 1, 2 or 3 Mean throughput class defined but not

used 'yes' Reordering Required

(Information in the SGSN and the GGSN PDP Contexts) 'no'

QoS parameters in GPRSQoS parameters in GPRS



QoS in UMTS Rel 99 & 4 (1/3)

• Target: try to guarantee end-to-end QoS in Packet from Rel 5 onwards: combine advantages of Packet -efficient use of radio resources- with the advantages of Circuit -guaranteed QoS.

• Potentially get rid of the Circuit domain in the (very) long term.

• Complex problem involving almost all the network elements.




• The end-to-end degradation (including delay) is the sum of the degradations caused by each hop

• The handling of QoS parameters has to be consistent on all different interfaces => involvement of many 3GPP groups



AccessNetwork 1

CoreNetwork(s)

User 1 AccessNetwork 2

User 2

End-to-end aspects

Hop-by-hop aspects




Different links defined

TE MT UTRAN CN IuEDGENODE

CNGateway

TE

UMTS

End-to-End Service

TE/MT LocalBearer Service

UMTS Bearer Service External BearerService

UMTS Bearer Service

Radio Access Bearer Service CN BearerService

BackboneBearer Service

Iu BearerService

Radio BearerService

UTRAFDD/TDD

Service

PhysicalBearer Service



Distinction between 4 QoS classes

Traffic class Conversationalclass

Streaming class

Interactive class

Background

Example of application

Voice Streaming video

Web browsing

Background download of emails

Fundamental characteristics

- Preserve time relation (variation) between information entities of the stream - Conversational pattern stringent and low delay

- Preserve time relation (variation) between information entities of the stream

- Request response pattern - Preserve payload content

- Destination is not expecting the data within a certain time- Preserve payload content

QoS parameters for UMTS (1/2)



QoS parameters for UMTS (2/2)

- Traffic class ('conversational', 'streaming', 'interactive', 'background') Then, according to the traffic class, a given subset of these parameters

applies:• Maximum bitrate (kbps) • Guaranteed bit rate (kbps) • Delivery order (yes or no)• Maximum SDU size (octets) • SDU format information (bits)• SDU error ratio• Residual bit error ratio• Delivery of erroneous SDUs (yes, no, don’t check)• Transfer delay (ms) • Traffic handling priority (1, 2 or 3)• Allocation/Retention priority• Source statistics descriptor (‘speech’/’unknown’)



Possible values

Traffic class Conversational class Maximum bitrate (kbps) < 2 048 Delivery order Yes/No Maximum SDU size (octets) <=1 502 SDU format information tbd Delivery of erroneous SDUs Yes/No/- Residual BER 5*10-2, 10-2, 5*10-3, 10-3, 10-4, 10-6 SDU error ratio 10-2, 7*10-3, 10-3, 10-4, 10-5 Transfer delay (ms) 100 – maximum value Guaranteed bit rate (kbps) < 2 048 Traffic handling priority Allocation/Retention priority 1,2,3

Extract for “Conversational Class”



QoS in the low layers

• In the Core Network:– It is operators' option which of QoS capabilities in IP layer

or QoS capabilities in ATM layer is used. For the IP based backbone, Differentiated Services defined by IETF shall be used. The mapping from UMTS QoS classes to Diffserv codepoints is controlled by the operator.

• For Bearer Service:– For IP based BS, Differentiated Services defined by IETF

shall be used. If operator chooses ATM-SVC as an internal dedicated transport bearer, inter operation with IP based networks will be based on Differentiated Services.



Mapping of QoS parameters between layers

• From Application Attributes to UMTS Bearer Service Attributes– This is an operator’s choice.

• From UMTS Bearer Service Attributes to Radio Access Bearer Service Attributes– Rules defined by the standard

• From UMTS Bearer Service Attributes to CN Bearer Service Attributes– This is operator's choice.

Documents

Quality of Service (QoS) - Universitas Indonesiastaff.ui.ac.id/system/files/users/ir.muhammad/material/sistel11qos.pdf · QoS Parameters Bandwidth – rate of flow of multimedia data