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for Africa (TAF) (TAF) for Africa Midrand, South Africa, June - - PowerPoint PPT Presentation

ITU/BDT Regional ITU/BDT Regional Seminar Seminar on on Costs and Tariffs for Member Countries of the Tariff Group Costs and Tariffs for Member Countries of the Tariff Group for Africa (TAF) (TAF) for Africa Midrand, South Africa, June


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June 2005

ITU/BDT NGN Network Architecture - O.G.S.

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ITU/BDT ITU/BDT Regional Regional Seminar Seminar on

  • n

Costs and Tariffs for Member Countries of the Tariff Group Costs and Tariffs for Member Countries of the Tariff Group for Africa for Africa (TAF)

(TAF)

Midrand Midrand, South Africa, June 2005 , South Africa, June 2005

NGN Network Architecture

Oscar González Soto ITU Consultant Expert Strategic Planning and Assessment

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NGN NGN Network Network Architecture Architecture Content Content

  • NGN concepts
  • Concepts and motivation
  • Requirements
  • Network architecture
  • Functional Network
  • Network elements and protocols
  • Network design issues
  • Dimensioning for multiple flows
  • Cost drivers and trends
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June 2005

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NGN NGN Network Network Architecture Architecture NGN concept

  • A multi-service network able to support voice, data and video
  • A network with a control plane (signaling, control) separated from

the transport/switching plane

  • A network with open interfaces between transport, control and

applications

  • A network using packet mode technology to transport of all kind
  • f information
  • A network with guaranteed QoS for different traffic types and SLAs
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NGN NGN Network Network Architecture Architecture Why Why

  • Flexibility for service building and offering
  • Expectation of cost reductions by sharing infrastructure and

systems

  • Simplification of O&M, thus lowering OPEX.
  • Use of open interfaces leads for:
  • quick deployment of services and applications
  • new services (third parties)
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NGN NGN Network Network Architecture Architecture NGN Layers NGN Layers

Network Independent Services Legacy Network Signaling/Service Legacy Network Media

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NGN NGN Network Network Architecture Architecture Target Target architecture architecture

Other Networks

DLC

Control Transport/Media Distributed Switching

DSL Trunk gateway Access gateway Wireless gateway Access gateway Access gateway

Softswitch

OSS Services

Packet Network

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June 2005

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NGN NGN Network Network Architecture Architecture Key Factors: Operator Requirements(I) Key Factors: Operator Requirements(I)

  • Business continuity required to maintain ongoing dominant services

and customers that require carrier-grade service

  • Flexibility to incorporate existing new services and react quickly to the
  • nes that appear on real time (main advantage of IP mode)
  • Profitability to allow feasible return on investments and in the best

practices market values

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NGN NGN Network Network Architecture Architecture Key Factors: Operator Requirements (II) Key Factors: Operator Requirements (II)

  • Survivabilty to allow service assurance in case of failures and external

unexpected events

  • Quality of Service to guarantee the Service Level Agreements for

different traffic mixes, conditions and overload.

  • Interoperabilty across networks to allow to carry end to end services

for flows in different network domains

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SLIDE 9

June 2005

ITU/BDT NGN Network Architecture - O.G.S.

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NGN NGN Network Network Architecture Architecture Content Content

  • NGN concepts
  • Concepts and motivation
  • Requirements
  • Network architecture
  • Functional Network
  • Network elements and protocols
  • Network design issues
  • Dimensioning for multiple flows
  • Cost drivers and trends
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NGN NGN Network Network Architecture Architecture Network Architecture Network Architecture

PBX

Softswitch

Media Gateway Controller IP/XX Network

Intelligent Network

  • Appl. Servers

Access Gateway Access Gateway

N7 Signalling

PSTN Access Gateway Trunking Gateway

H.248 H.248 H.248 H.248

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NGN NGN Network Network Architecture Architecture Network Elements Network Elements

  • Packet based networks

– Trend is to use IP based networks over various transport possibilities (ATM, SDH,

WDM…) – IP based networks must offer guarantees of Quality of Service (QoS) regarding the real time characteristics of voice, video and multimedia

  • Access Gateways

– Allows the connection of subscriber lines to the packet network

– Converts the traffic flows of analogue access (Pots) or 2 Mb/s access devices into packets – Provides subscriber access to NGN network and services

  • Trunking Gateways

– Allows interworking between classical TDM telephony network and Packet-based

NGN networks, – Converts TDM circuits/ trunks (64kbps) flows into data packets, and vice versa

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NGN NGN Network Network Architecture Architecture Network Elements Network Elements

  • Softswitch/MGC

– referred to as the Call Agent or Media Gateway Controller (MGC). – provides the “service delivery control” within the network – in charge of Call Control and handling of Media Gateways control (Access and/or Trunking) via H.248 protocol – performs signalling gateway functionality or uses a signalling gateway for interworking with PSTN N7 signalling network – provides connection to Intelligent Network /applications servers to offer the same services as those available to TDM subscribers

  • Application Server (AS):

– A unit that supports service execution, e.g. to control Call Servers and NGN special resources (e.g. media server, message server).

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NGN NGN Network Network Architecture Architecture Network Elements Network Elements

  • H.248 Protocol

– Known also as MEGACO: standard protocol, defined by ITU-T, for signalling and session management needed during a communication between a media gateway, and the media gateway controller managing it – H.248/MEGACO allows to set up, keep, and terminate calls between multiple endpoints as between telephone subscribers using the TDM

  • SIP

– Session Initiation Protocol in order to handle call establishment, maintenance and termination from packet mode terminals.

  • Signalling Gateway (SG):

– A unit that provides signalling conversion between the NGN and the other networks (e.g. STP in SS7).

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NGN NGN Network Network Architecture Architecture Network Elements Network Elements

  • ENUM

– Electronic NUMbering: Protocol that allows to establish a correspondance between the traditional telafone numbering (E.164 ) and the network addresses related to the packet mode networks ( RFC 2916 "E.164 number and DNS" IETF).

  • MPLS

– Multiprotocol Label Switch or protocol that assigns labels to information packets in

  • rder to allow the node routers to treat and route flows in the network paths

according to established priority for each category.

  • CAC

– Call Acceptance Control function in order to accept/reject traffic in the network that allows guarantee of QoS for services with a Service Level Agreement

  • BGP

– Border Gateway Protocol to negotiate flow routing procedures and capacities

across different NGN network domains

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NGN NGN Network Network Architecture Architecture Architecture Consolidation: Topology Architecture Consolidation: Topology

Topological changes impact on infrastructure and are slower to implement than technology substitution

  • Less network nodes and links due to the higher capacity of systems

(one order of magnitude).

  • Same capilarity at access level due to identical customer location
  • Topological connectivity higher for high capacity nodes and paths for

security

  • High protection level and diversity paths/sources in all high capacity

systems, both at functional and physical levels

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Smooth migration to NGN Smooth migration to NGN NGN NGN Network Network Architecture Architecture Overall Architecture Overall Architecture

Multiservice Node

Access Access Customers Customers Core Core

PSTN Class 4 Subscriber unit

RSP

DS

Data Mux

IN

Edge Edge

PSTN Class 5 SSP

International International Core Core

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NGN NGN Network Network Architecture Architecture Overall Architecture Overall Architecture

Multiservice node

Access Access Customers Customers Core Core

Subscriber unit MM

NGCR

Optical

AGW

Softswitch

Associated TK GW

Edge Edge International International Core Core

NGER

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NGN NGN Network Network Architecture Architecture Technological alternatives at core Technological alternatives at core

Lambda Bandwith Dark Fiber

Origin Scenario Circuit based Target Scenario Packet based

Managed

Multiservice ATM/FR/IP ATM VPN, IP VPN

Ethernet ptp LAN to LAN connection

Internet Gbit access IP VPN

Optical fiber Optical fiber DWDM equipment DWDM equipment Optical switching Optical switching SDH SDH IP Routing IP Routing Ethernet Ethernet

GigE GigE

ATM/FR ATM/FR

GigE,10/100BT Ficon,Escon, GigE,10/100BT Ficon,Escon,

Fibre Fibre Ch.. Ch..

IP IP Physical Infrastructure Physical Infrastructure

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June 2005

ITU/BDT NGN Network Architecture - O.G.S.

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NGN NGN Network Network Architecture Architecture Content Content

  • NGN concepts
  • Concepts and motivation
  • Requirements
  • Network architecture
  • Functional Network
  • Network elements and protocols
  • Network design issues
  • Dimensioning for multiple flows
  • Cost drivers and trends
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NGN NGN Network Network Architecture Architecture The Network Design Criteria The Network Design Criteria

  • A) Match realistic service demands and workloads for a given time

– Node and links loads based on proper multiservice flow characterization, measurements and projections

  • B) Consider equilibrium between QoS and cost

– Statistical behavior for the flows – Traffic modeling for given quality, efficiency and protection – Overload protection and control

  • C) Anticipate capacity as a function of service grow rate and needed

installation time. Reserve capacity

  • D) Follow SLA when different service classes coexist
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NGN NGN Network Network Architecture Architecture Network Design Network Design and and Dimensioning Dimensioning The 5 basic Traffic activities The 5 basic Traffic activities

  • Traffic Characterization for services and network flows
  • Traffic Demand forecasting and aggregation at the user and

Network interfaces

  • Traffic Dimensioning for all network elements
  • Traffic Measurements and Validation for key parameters
  • Traffic Management in focussed and generalized overload
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NGN NGN Network Network Architecture Architecture Network Design Network Design and and Dimensioning Dimensioning

Service demand Characterization

– By a profile through days in a year/week – By a busy period within a day – By superposition of non-coincidence of busy periods (for inter- country traffic in different time zone) – By aggregation or convolution of flows for different services – By interest factors between areas (adjusting matrices in the two dimensions ie: Kruithof, affinity, correlation)

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NGN NGN Network Network Architecture Architecture Traffic Characterization Traffic Characterization

  • Aggregated average traffic per level as a weighted average of the services (i)

and customer classes (j) at that level.

  • Generalized utilization time and levels per user activity

in the busy period : Example for IP mode

Activity/Connection time at Application level Customer Service time at Session level Communication time at Burst level Transmission time at Packet level

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NGN NGN Network Network Architecture Architecture Traffic Traffic Characterization Characterization

  • Different relation between peak traffic and average traffic per service classes:

CBR (1), VBR(2), VBR(3)

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NGN NGN Network Network Architecture Architecture Traffic Characterization Traffic Characterization

  • Traffic Units definition

– At call, session and packet level – Needed additional clarification on the different type of traffic averages and meaning (CBR,SBR, Billed)

  • Reference periods

– Should be common when aggregating services to ensure validity and represent behavior of IP flows

  • Statistical laws

– For calls, sessions and packets

  • Aggregation process

– Considering reference period above and coincidence/non- coincidence of busy periods among services

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NGN NGN Network Network Architecture Architecture Traffic Traffic flow flow types types for for Quality Quality of

  • f Service

Service based based dimensioning dimensioning

– QoS constant stream: bandwidth transmission at a constant speed with a specified delivery and jitter (ie: video distribution) – QoS variable stream : bandwidth transmission at a variable speed derived from a user information and coding algorithm which requires guaranteed quality and specified jitter (ie: VoIP, Video streaming, audio streaming, etc.) – QoS elastic: bandwidth transmission at a variable speed without jitter restrictions and asynchronous delivery (ie: browsing, file transfer, mail, UMS, etc.)

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NGN NGN Network Network Architecture Architecture Traffic Flows to be modeled Traffic Flows to be modeled

  • L1) Global Network Level

– Overall topological network (access and/or core) including routing procedures and all alternative paths.

  • L2) End to End Path or sub-path

– For different user type scenarios: VoIP to VoIP, VoIP to POTS, etc. and network segments: user to LEX, user to GW, etc.

  • L3) Network Elements

– For Network Nodes

  • LEX, RSU,POP,GW, SS, TGW,IP router, etc.

– Network Links

  • At functional, transmission and physical levels

To simplify analysis, the following partition is made:

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NGN NGN Network Network Architecture Architecture NGN NGN Service Service demand demand evaluation evaluation process process

Traffic aggregation per O/D and flow category Traffic matrices Services per customer type Traffic per service/customer type

Services projection Mapping services per customer Traffic units per service (multi-service IP) Traffic aggregation per customer type Traffic aggregation per IP flow category Traffic flow aggregation per O/D Matrix per IP flow category (original BW) Dimensioning matrix (capacity BW)

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NGN NGN Network Network Architecture Architecture Cost drivers and trends Cost drivers and trends

  • Network physical infrastructure as a function of location and density

(costs proportion around 70% in the access segment)

  • Volume of customers per category
  • Bandwidth demand per origin/destination
  • Packet processing rates for control related functions
  • Variety of applications/services and related platforms
  • Content storage and location within the network
  • Leasing of physical or communication resources

Fundamental importance of economies of scale by volume and convergence at network resources, service platforms and OSS

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NGN NGN Network Network Architecture Architecture Cost drivers and trends Cost drivers and trends

Cost trends for NGN

  • Cost reduction in CAPEX due to technological economy of scale by

larger capacities

  • Similar values for costs in the physical civil infrastructure
  • OPEX in NGN trends to be lower due to the integrated operation and

maintenance

  • Plan higher investments in security/survivability with diversity paths

and protection for large capacity systems Check and validate correct cost modelling with fixed and variable components as a function of economy of scale

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NGN NGN Network Network Architecture Architecture Summary of Key Concepts Summary of Key Concepts

  • Multimedia open service network.
  • Applications and control functions separated from media
  • Guarantee of Quality of Service needed
  • Motivated by new services, flexibility and cost reductions
  • Maturity level progressing and needing consolidation