Services Overview46FD 100/320Gbps NT and FX NT IHub Services Guide3HH-11985-AAAA-TQZZA Issue: 133.2 IntroductionA service is a globally unique entity that refers to a type of connectivity service foreither Internet or VPN connectivity. Each service is uniquely identified by a serviceID within a service area. The ISAM service model uses logical service entities toconstruct a service. In the service model, logical service entities provide a uniform,service-centric configuration, management, and billing model for serviceprovisioning.Services can provide Layer 2/bridged service or Layer3/IP routed connectivitybetween a Service Access Point (SAP) on one ISAM and another service accesspoint (a SAP is where end-user traffic enters and exits the service). A distributedservice over the Internet requires that ISAMs are interconnected via SR-Seriesrouters.Distributed services use service distribution points (SDPs) to direct traffic to anotherPE through a service tunnel. SDPs are created on each participating ISAM/servicerouter, specifying the origination address (the ISAM participating in the servicecommunication) and the destination address of another ISAM/service router. SDPsare then bound to a specific customer service. Without the binding process, far-endservice router/ISAM devices are not able to participate in the service (there is noservice without associating an SDP with a service).3.2.1 Service TypesThe ISAM offers the following types of subscriber services which are described inmore detail in the referenced chapters:• Virtual Private LAN Service (VPLS) — ISAM supports three types of VPLSservices: v-VPLS (VLAN VPLS), m-VPLS (management VPLS) and VPLS.v-VPLS forwarders emulate the ISAM bridging service in the IHUB. v-VPLSforwarders enable frames to be L2 forwarded between user side and network sidethough IHUB and extend the reach of a VPRN IP interface (SAP) to severalphysical ports. The m-VPLS forwarder is exclusively used to handle L2CP frames(for example, spanning tree). The m-VPLS is not intended to forward data traffic.For more information see “Virtual Private LAN Service”. VPLS (a Layer 2multipoint-to-multipoint VPN) enables frames to be L2 forwarded between theuser side and the MPLS network side. Frames are encapsulated in MPLS Pseudowires (PW).• Internet Enhanced Service (IES) — A direct Internet access service where thecustomer is assigned an IP interface for Internet connectivity. See “InternetEnhanced Service”.• Virtual Leased Line Service (VLL) - Ethernet pipe (Epipe) — A Layer 2point-to-point VLL service for Ethernet frames. See “Ethernet Pipe (Epipe)Services”.• Virtual Private Routed Network (VPRN) — A Layer 3 IP multipoint-to-multipointVPN service as defined in RFC 2547bis. See “Virtual Private Routed NetworkService”.
