Technical White Paper For Seamless MPLS Networking

Transcription

Technical White Paper forSeamless MPLS Networking

Contents1 Preface.21.1 Metro Bearer Technology in the TR101 Architecture. 21.2 Introduction of Seamless MPLS Networking Technologies. 52 The Value of Seamless Networking Technology.72.1 Unified and Simplified Bearer Technology. 72.2 Flexible and Scalable Network Architecture. 72.3 Quick Service Provision to Improve User Satisfaction. 92.4 Maturity and Reliability of IP/MPLS and OAM Technologies. 103 Implementing the Seamless MPLS NetworkingTechnology.113.1 Challenge of the Seamless MPLS Networking Technology. 113.2 Seamless MPLS Area-Based Networking. 123.3 Seamless MPLS AS-Based Networking. 154 Key Technologies.174.1 Inter-area LDP. 174.2 Service Driven LDP DoD. 184.3 MPLS Load-Balancing Label (MPLS Flow Label). 184.4 Fast Convergence Technology. 20

4.4.2 LDP FRR Convergence Technology. 204.4.3 BGP FRR Convergence Technology. 214.5 OAM Technology. 225 Applications.245.1 Flexible Service Wholesale. 245.2 Inter-Metro VPLS Private Line. 245.3 ATM DSLAM Migration. 266 Conclusion.287 Appendix A References.298 Appendix B Acronyms and Abbreviations.30

Technical White Paper forSeamless MPLS NetworkingKeywords:Seamless; MPLS; Scalability; Reliability; OAM; LDP DoD; PWE3Abstract:Seamless MPLS networking refers to the formation of a unified IP/MPLScontrol plane for all the IP devices managed by operators, includingaccess (fixed/mobile), convergence, and backbone devices. TheSeamless MPLS networking architecture greatly reduces cooperationbetween different network layers when services are deployed, allowsoperators to quickly provide services, and lowers deployment costs.Reliability/OAM detection can be deployed easily through the endto end IP/MPLS control plane and unified networking technology.This document describes the background, challenges, solution, andapplication scenarios of the Seamless MPLS.1

1 PrefaceWith the wide application of Multiprotocol Label Switching (MPLS)technology, operators establish Metropolis Area Networks (MANs) andbackbone networks for the bearing of integrated services by usingthe MPLS-based L3VPN/L2VPN solution. Generally, services and usersare identified through 802.1Q or 802.1ad between access devices,MAN, and backbone networks, requiring the static configuration ofinterfaces between each layer. In seamless networking, the end-toend IP/MPLS networking of all data devices managed by operators isrealized, including access (fixed/mobile), convergence, and backbonedevices. This is achieved by eliminating the existing 802.1Q/802.1adinterface between devices on each layer in the existing network. Thus,each layer can implement dynamic interaction, which is called ‘end-toend big networking’. This chapter describes the problems with existingnetworking architecture, and the benefits of Seamless MPLS architecture.1.1 Metro Bearer Technology in the TR101 ArchitectureThe TR101 in the DSL forum draft specifies the DSL aggregation modelin Ethernet 0-NSPL2TSIP - QoSA10-NSPIPBBNetworkGatewayIP - QoSA10-NSP Regional MDF LoopVAccess NetworkNetworkUser1NDCPETUser2U Customer Prem.NetAggregation NetworkFigure 1 TR101 Ethernet DSL aggregation model2

The model defines the V interface between the access node andEthernet convergence network/node to identify different DSL portsfor services and user access through the 2-layer TAG of 802.1ad(QinQ).The mainstream networking technologies of the metro convergencenetwork include Ethernet enhanced technology (QinQ, PBB), MPLSbearer, and L3 Hybrid. The Ethernet enhanced modes, such as QinQand PBB, effectively improve network reliability and service flexibility.The MPLS bearer mode is one of the mainstream bearer technologiesof the Ethernet convergence network, as it facilitates VLAN scalabilityand reliability. In L3 Hybrid mode, services are classified into edgeprocessing services and transparently transmitted services, accordingto service features. For the edge processing services, the IP edge islocated in the edge convergence node. Transparently transmittedservices are sent to the specified POP point through the MPLS pipe.The Hybrid mode can adapt to service development requirements inthe future.PPPOE VLANVPLSVPLSVPLSVPLSVPLSAGGUPEPPPOE VLANVOD VLANIPTV VLANL2VPN VLANL3VPN VLANVPLSIPTV VLANL2VPN VLANL3VPN VLANAGGAGGVOD VLANUPEDSLAM/OLTDSLAM/OLTL3 HybridModeMPLSModeIn these metro convergence network technologies, the V interfacespecified in TR101 architecture is used. The following figure showsthe bearer modes of services in the network position in MPLS modeand L3 hybrid mode.PPPOE VLANVOD VLANIPTV VLANL2VPN VLANL3VPN VLANBRASPPPOE VLANL3VPNBRASIP MulticastL2VPNL3VPNSRPESRIA,Native IPL3VPNIP MulticastIXCCSVHOL2VPNL3VPNIA, Native IPIXCCSVHOPFFigure 2 Service bearer model of the TR101 architecture3

With the continuous development of user access requirements andservices, network operators must meet these new requirements.TR101 architecture cannot meet these new requirements.1. For FTTX access, the wholesale service mode of the ULL cannot bemaintained. POP point locations vary with the scale of alternativeoperators. Therefore, incumbent operators must provide a moreflexible connection capability at the access node (AN). In this case,the AN must identify alternative operators, services, and users.For TR101 architecture, the complicated VLAN planning is requiredon the V interface due to the limitation of the VLAN space. Ina typical metro MPLS networking scenario, the VLAN must beconfigured in more nodes (AN, UPE, AGG, and PE) of incumbentoperators if the POP point location of alternative operators is not inthis local MAN.2. Connecting the inter-metro enterprise private line is required dueto the quick development of the enterprise Ethernet private line.Multi-point static configuration in the TR101 architecture isrequired. The inter-metro Ethernet private line can be providedthrough cooperation between the management entities on eachlayer.3. According to Fixed-Mobile Convergence (FMC) requirements, theAN must be accessed to the mobile bearer services to connect thebase station and mobile gateway, including ATM, TDM, and theEthernet.4. The function of the IP bearer network is more important due toservice access density and the migration of telecom services. Usersrequire greater access reliability.In TR101 architecture, the networking technologies on eachlayer are not unified and different reliability solutions are used.Cooperation and interaction are complicated without a maturestandard. Device manufacturers provide solutions of differentreliability and the interoperability problem cannot be solved.4

1.2 Introduction of Seamless MPLS NetworkingTechnologiesWith Seamless MPLS architecture, the entire network uses unified IP/MPLS networking technology, with an end-to-end control plane. As aresult, the V interface between the AN and Ethernet convergence iseliminated. The above problems are solved. Through Seamless MPLSnetworking technology, operators can flexibly handle connectionrequirements so that services are provided quickly. Thus, new servicesare deployed quickly and service deployment costs are reduced, whichstrengthens the competitiveness of operators.In addition to the V interface between the access and convergencenetwork, the VLAN may be configured for service interconnectionbetween the MAN and backbone network. Seamless MPLS networkingcan meet this requirement and enable dynamic establishment throughthe end-to-end MPLS pipes for inter-metro services.In the Seamless MPLS networking model, all services can betransferred to the specified service processing points through the MPLSpipe at service access points. The entire bearer solution is simple andconsistent. With the dynamic end-to-end MPLS pipe establishmentcapability, services can be transferred to any service processing pointsor peer service access points through the MPLS pipe/PWE3 pseudowire, according to requirements.AccessMetro AggregationMetro AggregationAccessMPLS DomainOLT/DSLAMBNGSRGCSGIP IGP FC / MPLS OAM / MPLS FRRFigure 3 Seamless networking model5

Seamless MPLS networking technology is not new and is widelyapplied to backbone networks, MANs, and the mobile backhaul.Application experiences indicate that Seamless MPLS networking is amature and reliable bearer technology with excellent scalability. TheSeamless MPLS can eliminate the gap between network layers toimplement end-to-end MPLS networking.6

2 The Value of SeamlessNetworking Technology2.1 Unified and Simplified Bearer TechnologyWith seamless networking technology, the access (fixed/mobile),convergence, and backbone devices connect through the unified IP/MPLS control layer.2.2 Flexible and Scalable Network ArchitectureFuture-oriented networking technology must provide a more flexibleand scalable network architecture. Currently, the development ofsome services indicates that more flexibility and better scalability arerequired.1. Service wholesale in FTTX accessIn the case of the copper access, the LLU is the main wholesalemode. In the case of the FTTX access, the LLU is not applicable. Thebit stream access will become the mainstream wholesale mode.Network Open PointCopper Access ModeLocalExchangeCustomerCopper Access1) Copper ULLMetro POP2) PVC/VLAN Bit streamStreet/Building3) L2TP WholesaleNetwork Open PointFTTx Access ModeCustomerIP CoreLocalExchangeMetro POPIP CoreFigure 4 Service wholesale in the copper and FTTx access scenarios7

The POP device can be deployed in any network layer according tothe network scale of the competitor operator. For BSA wholesale, thenetwork must be flexible and simple so that wholesale user servicescan be handed over to a competitor operator at any point. Throughend-to-end MPLS pipes between the ANs and service transfer points,seamless architecture meets flexible connection requirements. InTR101 architecture, the AN, convergence devices, and service transferpoints are configured. When the service transfer points are in theinter-metro area, the distributed nodes and backbone PE devices in theMAN must be configured.TR101Sometimes, the competitor operator needs to identify different usersand services through the 2-layer VLAN TAG. To meet this requirement,the incumbent operator must identify the competitor operator andits users and services on the AN. If TR101 architecture is used, thedistribution policy of the S-TAG and C-TAG must be planned carefully.In the seamless architecture, the PW identifies different competitoroperators. It is easier to identify users and services.Identify thewholesaleoperators,services,and usersEnd userANIdentify thepipe forentering themetro by VLANQinQUPELeave the metropipe, use the VLANto identify thewholesale operatoragainPE-AGGQinQEnter thebackbonepipe byVLANsPESeamlessIdentify services andusers. Enter thePWE3 pipeaccording towholesale operators.Leave thebackbone pipePEQinQThird PartyrouterLeave thepipeQinQEnd userPEANMPLS Tunnel/PWE3Third PartyrouterFigure 5 Service wholesale deployment comparison between the seamless and TR1012. Deployment of inter-MAN enterprise Ethernet private servicesEnterprise Ethernet services are not limited just in the MAN. Theconnection of Ethernet private lines may be required betweenMANs. In TR101 architecture, multiple nodes such as accessnodes, metro UPE, metro PE-AGG, and the backbone PE must beconfigured to provide Ethernet private line services between the8

inter-metro DSLAMs. In addition, the VLAN planning is required.In seamless networking, only the access nodes on both sides areconfigured in the dynamic PWE3 mode to provide Ethernet privateline services.TR101Service configuration pointMetro 1CPEANUPEPE-AGGcorePEMetro 2PEPE-AGGUPEAN CPEUPEAN CPESeamlessService configuration pointSeamless MPLSCPEANUPEPE-AGGPEPEPE-AGGFigure 6 Comparison of deployment of inter-metro private line services between the Seamless and TR1012.3 Quick Service Provision to Improve UserSatisfactionTo provide wholesale and enterprise private line services under TR101architecture the access, metro, and backbone devices of differentlayers must cooperate. For service deployment, cross-departmentalcoordination is required between the management entities of differentlayers. As a result, it takes a long time to provide services.With seamless networking, operators need to only configure useraccess points. Services can be provided quickly, user satisfactionincreases, and service deployment costs are reduced. Thus, operators’competitiveness is strengthened.9

2.4 Maturity and Reliability of IP/MPLS and OAMTechnologiesBased on IP/MPLS technology, seamless networking easily implementsend-to-end protection through the reliable

Enterprise Ethernet services are not limited just in the MAN. The connection of Ethernet private lines may be required between MANs. In TR101 architecture, multiple nodes such as access nodes, metro UPE, metro PE-AGG, and the backbone PE must be configured to provide Ethernet