Performance Aspects of NGN

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Performance Aspects of NGN

• Hyungsoo, KIM

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Terminologies

• ITU-T Recommendation E.800 (94.08)
• Quality of Service is a collective effect of
  service performances which determine the degree
  of satisfaction of a user of the service
• ITU-T Recommendation I.350 (93.03)
• Network Performance is measured in terms of
  parameters which are meaningful to the network
  provider and are used for the purposes of system
  design, configuration, operation and maintenance
• ITU-T SG12
• Quality of Experience is the overall
  acceptability of an application or service, as
  perceived subjectively by the end-user.

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Quality of Experience

• Service acceptability (satisfaction) depends on a
  users expectation
• Case 1 the service purpose
• the same quality of VoIP
• web-phone on PC for personal gt telephone for
  business
• Case 2 the expected and consistent quality is
  preferred
• 384 kbps video of stable quality gt 1Mbps video of
  unstable quality
• Case 3 the expense of service
• the same quality of streaming video
• free gt charged (low price gt high price)

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QoS/NP/QoE on NGN
(ITU-T Focus Group on NGN, TR-NGN.QoS)
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Relationship among three components
QoE (User)
? Voice ? Video ? Data ? Call Control
? Voice ? Video ? Data ? Call Control
QoS (Application)
Service Platform
Service Platform
Network Performance (Network)
NI
NI
Terminal
Terminal
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ITU-T Recommendations

• QoS related ITU-T Recommendations
• G.1000 Communications quality of service A
  framework and definitions
• G.1010 End-user multimedia QoS categories
• TR-NGN.QoS General aspects of QoS/NP
• Network Performance related ITU-T Recommendations
• I.356 B-ISDN ATM layer cell transfer
  performance
• Y.1541 Network performance objectives for
  IP-based services
• Y.1561 Performance and availability parameters
  for MPLS networks
• TR-NGN.NHNperf. Network performance of
  non-homogeneous network in NGN
• QoE related ITU-T Recommendations
• P.800 Methods for subject determination of
  transmission quality
• G.114 One-way transmission time
• G.107 The E-model, a computational model for
  use in transmission planning
• G.OMV opinion model for videophone applications

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Four viewpoint for QoS

• Translation into
• the network-oriented

• Quantifying of
• required quality

(ITU-T SG12, Recommendation G.1000)

• Network/service
• Engineering

• Evaluation

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Quantifying of required quality (1)

• Application QoS (G.1010)
• An applications required quality-based (Network
  QoS CPN/CPE QoS)
• Focusing on IP-based Network
• In case that an users performance requirements
  doesnt exist
• Other new applications should be specified
• DMB,
• IP-TV (more stringent level),
• Converged services, etc.

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Quantifying of required quality (2)

• Application QoS Classes (TR-NGN.QoS)
• Too many applications in NGN (existing
  applications innovative applications)
• Expense-based Policy (VoIP/VoD High QoS/Low QoS
  ???)

Packet
Loss

5
High
Middle
Best Efforts
Low
100 s

100 ms
10 s
1 s



0
Delay



Zero
loss
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Translation into the network-based (1)

• IP-based network performance Y.1541

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Translation into the network-based (2)

• ATM-based network performance I.356

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Translation into the network-based (3)

• Network performance of non-homogeneous networks
  in NGN (TR-NGN.NHNperf.)

Note These QoS classes have the performance
objectives which is more tolerable than the
stringent QoS classes, especially on delay
variation- and loss-related performance
parameters. It is not certain that an individual
QoS class should be mapped to each other (IP QoS
classes 2, 3 4 and ATM QoS classes 2 3).
This is for further study.
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Translation into the network-based (4)

• Performance allocation (Y.1541, I.356, etc.)
• Based on the number of nodes and the link distance

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Translation into the network-based (5)

• Performance Budget Allocation (TR-APO)

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Network/Service Engineering (1)
ANF - Access Node Function ENF - Edge Node
Function NACF - Network Attachment
Control Functions BGF - Border Gateway
Function R-BGF - Residential BGF A-BGF - Access
BGF I-BGF - Interconnection BGF IBCF
Interconnection Border Control Function PDF -
Policy Decision Function TRCF - Transport
Resource Control Function A-TRCF Access
TRCF C-TRCF -Core TRCF SCPF Session Control
Proxy Function
Service Control Functions
SCPF
. . .
IBCF
Service Stratum
Gq
Transport Stratum
Rd


NACF
Iq
RACF
Functions in other NGNs
PDF
Ub
Rq
Rp
Rq
C-TRCF
A-TRCF
Re
Rc
Rc
Re
Go
Go
R-BGF
ANF
ENF
A-BGF
I-BGF
CPN
Core Transport
Access Transport
TR-RACF (Resource and Admission Control Function)
Work in progress

• Dynamic management of transport resources (e.g.,
  bandwidth or IP addresses) as dictated by
  application needs and operator policy to achieve
  end-to-end QoS and border control (e.g., NAPT and
  packet filtering)
• Bridging service control of a variety of
  applications (e.g., telephony and multimedia
  streaming) and transport of varied technology and
  domains
• Admission decision taking into consideration
  resource availability
• Arbitration of many-to-many relationship based on
  policy

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Network/Service Engineering (2)
Q Series Supplement 51
IP QoS Signalling Requirements (TRQ.IPQoS.SIG.CS1)

• Performance parameters signalled, e.g.,
• Y.1541 QoS class, reliability/priority levels,
  DSCP, accumulated performance
• Capabilities supported, e.g.,
• Request-offer-answer exchanges
• Flow control for QoS requests, congestion
  awareness
• Contention resolution for resource allocation
• Performance requirements for QoS requests (e.g.,
  max delaylt1500 ms)

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Evaluation (1)
Inter-Domain Performance Measurement and
Management (TR-pmm)

• Attributes to be measured
• Mean delay, delay variation, packet loss, path
  unavailability
• How attributes are measured, e.g.,
• Active or passive measurement
• Active probes tailored to service classes (e.g.,
  telephony, low latency data)
• Clock synchronization to Coordinated Universal
  Time through GPS and the like
• Algorithms for computing performance
• Management requirements, such as for discovery
  and inter-PRS communication

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Evaluation (2)

• R-value (e-model-based) G.114

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Evaluation (3)

• Object Quality Assessments Model

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SUMMARY

• Quantifying of required QoS
• - Performance-based
• - Expense-based ()

• Translation into the network
• -oriented
• - Fixed Allocation
• - Budget Allocation ()

• Network/service Engineering
• - Providers own policy
• to meet QoS requirements

• Evaluation
• - Monitoring Measurement
• - Evaluation of QoE

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