1.3 NGN architecture and main elements.ogs.pdf - BTCl

ITU-D Workshop on NGN MigrationStrategies and Access ModernizationNGN Architecture and Main ElementsDhaka, BangladeshMay 2011Oscar González SotoITU Consultant ExpertSpainoscar.gonzalez-soto@ties.itu.intDhaka, Bangladesh, May 2011ITU -NGN elements - OGSInternationalTelecommunicationUnion

NGN Concepts and Elements• Motivation and concept• NGN Architecture• Network ElementsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

Motivation: PremisesStrategic Trendsdata traffic (bandwidth) will become 2 to 5 times higherthan the voice traffic.IP is becoming the universal transport protocol used by allservicesHow PSTN should evolve ?as before, with its dedicated optimised technology (TDM) ?or move to packet IP networks, telephony being a serviceamong others ?Background reasons to evolveservice merge and new servicesDSL and other broadband access penetrationcost of ownership: unique instead of separated networksDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

Motivation: NGN concept•A multi-service network able to support voice, data andvideo•A network with a control plane (signaling, control) separatedfrom the transport/switching plane•A network with open interfaces between transport, controland applications•A network using packet mode technology to transport of allkind of information•A network with guaranteed QoS for different traffic types andSLAsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

Motivation: Why• Flexibility for service building and offering• Expectation of cost reductions by sharinginfrastructure 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)Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

NGN Concepts and Elements• Motivation and concept• NGN Architecture• Network ElementsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

General functional modelfor NGNInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion7

NGN Architecture andNetwork ElementsIntelligent NetworkAppl. ServersAccess GatewayN7SignallingSoftswitchMedia GatewayControllerH.248H.248H.248PBXPSTNTrunkingGatewayIP/XXNetworkH.248Access GatewayAccess GatewayInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion8

Network Architecture:Existing networks and architectureSCPSS7POTSLEX/TEXLEXRSUNMCPCMINISDNTDMDhaka, Bangladesh, May 2011MobNASDataATM/IPMUX/DSLAMHDSL/XDSL• 5 different network types tohandle telecom services• TDM for fixed and mobilenetworks working in circuitmode with end to endreserved paths• SS7 and IN network workingwith message switching mode• Data network working withleased lines and packet modewith different andconventional IP protocolsITU - NGN elements - OGSInternationalTelecommunicationUnion

Network ArchitectureExisting networks and architectureNATIONAL LAYERREGIONAL LAYERLEXLAYERRULAYERcustomersLAYERDhaka, Bangladesh, May 2011TRANSIT NETWORKITU - NGN elements - OGS• Hierarchical topology with 4to 5 layers, connectivity to theupper next layer and withineach layer as a function ofeconomical optimization• Number of nodes as afunction of O/D traffic andnodes capacity• Service handling for media,signaling and control at allexchange nodes•Carrier grade quality withwell defined QoS criteria andstandardized engineeringrulesInternationalTelecommunicationUnion

Network Architecture:Old and New structuresSCPSS7LEX/TEXLEXNMCINMobTDMNASDataATM/IPControlOSSTransport/MediaAccessgatewayAccessgatewayServicesSoftswitch/IMSPacketNetworkIP/MPLS/CACDistributed SwitchingTrunkgatewayAccessgatewayOtherNetworksPCMDSLRSUPOTSISDNMUX/DSLAMWirelessgatewayDLCHDSL/XDSLInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 11

NGN Architecture and Elements• Motivation and concept• NGN Architecture• Network ElementsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

NGN Network ElementsPacket networksInformation is packetized in variable packet sizes with controlheaders to allow appropriate routing and deliverytrend is to use IP based networks over various transportpossibilities (ATM, SDH, WDM…)IP networks must offer guarantees of Quality of Service (QoS)regarding the real time characteristics of voiceIPv4Internet Protocol at network level that insert headers for eachpacket in order to allow end to end packet flows: v4 is the firstwidely used version with 20 octet headerIPv6Internet Protocol at network level that insert headers for eachpacket in order to allow end to end packet flows: v6 is the latestversion with 40 octet header and adding capabilities for currentrequirements in addressing and routingDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

NGN Network ElementsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion

NGN Network ElementsSoftswitch/MGCreferred to as the Call Agent or Media Gateway Controller(MGC).provides the “service delivery control” within the networkin charge of Call Control and handling of Media Gatewayscontrol (Access and/or Trunking) via H.248 protocolperforms signalling gateway functionality or uses a signallinggateway for interworking with PSTN N7 signalling networkprovides connection to Intelligent Network /applicationsservers to offer the same services as those available to TDMsubscribersApplication Server (AS):A unit that supports service execution, e.g. to control CallServers and NGN special resources (e.g. media server, messageserver).Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 16

NGN Network ElementsH.248 ProtocolKnown also as MEGACO: standard protocol, defined byITU-T, for signalling and session management neededduring a communication between a media gateway, and themedia gateway controller managing itH.248/MEGACO allows to set up, keep, and terminate callsbetween multiple endpoints as between telephonesubscribers using the TDMSIPSession Initiation Protocol in order to handlecommunication signalling and negotiation like callestablishment, maintenance and termination from packetmode terminals. Has a distributed peer to peerimplementationDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 17

NGN Network ElementsSignaling Gateway (SG):A unit that provides signaling conversion between theNGN and the other networks (e.g. STP in SS7).ENUMElectronic NUMbering: Protocol that allows to establish acorrespondence between the traditional telephonenumbering (E.164 ) and the network addresses related tothe packet mode networks ( RFC 2916 "E.164 number andDNS" IETF).Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 18

NGN Network ElementsMPLSMultiprotocol Label Switch or protocol that assigns labels toinformation packets in order to allow the node routers to treat androute flows in the network paths according to established priorityfor each category. Establishes a tunnel for an end to endforwarding. A label is a short, fixed length, locally significantidentifier which is used to identify a "Forwarding EquivalenceClass" (FEC ) to which that packet is assigned."LSPLabel-switched paths: An LSP is a specific traffic path that usingconvenient protocols will establish a path through an MPLSnetwork and will reserve necessary resources to meet pre-definedservice requirements for the data path.Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 19

NGN Network ElementsOSPFOpen Shortest Path First: A routing protocol thatdetermines the best path for routing IP traffic over a TCP/IPnetwork based on distance between nodes and severalquality parameters. OSPF is an interior gateway protocol(IGP), which is designed to work within an autonomoussystemBGPBorder Gateway Protocol: performs inter-domain routing inTCP/IP networks, handling routing between multipleautonomous domains. Routers use BGP to maintain aconsistent view of the internetwork topologyDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 20

NGN Network ElementsTraffic Engineering ModuleTraffic Engineering refers to the process of selecting the paths (LSPs) inorder to balance the traffic load on the various links, routers, and switchesin the network. A major goal of Traffic Engineering is to facilitate efficientand reliable network operations with guarantee of QoS whilesimultaneously optimizing network resource utilization and trafficperformanceCACCall Acceptance Control function in order to accept/reject traffic in thenetwork that allows guarantee of QoS for services with a given ServiceLevel AgreementDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion21

NGN Network ElementsIMSIP Multimedia Subsystem: architectural framework for deliveringIP multimedia services. It was originally designed by the wirelessstandards body 3 rd Generation Partnership Project (3GPP) formobile services and later extended to all types of networks.It has a multilayer structure with a transport stratum and a servicestratum containing all transport, control and application functionsas well as defined interfaces to external 3 rd party applications,OSS, BSS, NM and other networks.Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion22

NGN Network ElementsDiameterThe Diameter base protocol defines the minimum requirements forAuthentication, Authorization and Accounting (AAA) in an IMS networkand is the successor of the Radius protocol by incorporating advancedfunctionalities.IPsecIPsec is an end-to-end security scheme operating in the Internetlayer within a protocol suite including among others the ESP(Encapsulating Security Payload) . It can be used in protecting dataflows between a pair of hosts (host-to-host), between a pair ofsecurity gateways (network-to-network), or between a securitygateway and a host (network-to-host). Used procedure is by meansof authentication and encryption of each IP packet of acommunication session.Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion23

NGN Network ElementsIMS ArchitectureInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 24

NGN Network ElementsIMS Functional Structure andInterfacesOther IP Multimedia NetworksASPSTNMmISCShMbMbMGW BGCFMbMRFPPSTNMkMjMnMpMGCFMRCFBGCFMgMrCSCFMwMiCSCFP - CSCFMwHSS(AAA+DB)CxDxDhSLFMbGqGmIP Connectivity Access NetworkUEInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 25

NGN Network ElementsIMS ArchitectureIMS main functional elements:•Application Server (AS)• Voice Application Servers (VAS)• Instant Messaging (IM)•Home Subscriber Server (HSS)•Call Session Control Function (CSCF)•Breakout Gateway Control Function (BGCF)•Media Gateway Function (MGW)•Media Gateway Control Function (MGCF)•Multimedia Resource Function Controller (MRFC)•Multimedia Resource Function Processor (MRFP)InternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 26

NGN Network ElementsIMS ArchitectureApplication Server (AS)• Contains Call Related Application Logic• Facilitates a Service Creation Environment• Queried by S-CSCF in Real Time to Execute Logic• Generally Specialized for Each Service• May Provide Gateway to Legacy Applications (e.g. AIN)InternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 27

NGN Network ElementsFlow control at core NGNInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 28

NGN Network ElementsFlow control at core NGNInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 29

NGN Network ElementsFlow control at core NGNInternationalTelecommunicationDhaka, Bangladesh, May 2011 ITU - NGN elements - OGSUnion 30

NGN Concepts and ElementsStatus today• Available today for application in many networksfort most elements• Recently defined functionalities and interoperationstandardized and being deployed with adjustmentsneeded• Careful planning needed for operators with existinginfrastructure and operation (migration, profitability,QoS and survivability)Dhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnionslide 31

NGN Concepts and ElementsSummary of main factors• Main advantage of NGN based on IP is theflexibility for many services• NGN for all services with required quality is notjust IP or internet• Most functionalities and performance for publicnetworks in operation today. Some multi-domaininteroperation requiring agreementsDhaka, Bangladesh, May 2011ITU - NGN elements - OGSInternationalTelecommunicationUnion