ApplicAtion note w w w . a d c . c o m • + 1 - 9 5 2 - 9 3 8 - 8 0 8 0 • 1 - 8 0 0 - 3 6 6 - 3 8 9 1 LoopStar ® 700 Circuit Emulation Technology Extends TDM Services Over Packet Networks Overview Traditional voice and private leased-line traffic continues to provide significant revenues for metro service providers, while at the same time, packet-based traffic is growing exponentially. This incongruity ultimately requires metro networks to determine the most cost-effective and strategic way to serve two masters: the traditional time-division multiplex (TDM) world, or the emerging packet world that represents the revenue future. In many cases, the right solution is the one that extends the patented “circuit-over-IP” technology value of existing TDM services while optimizing the network for new revenues from packet services. It is the solution that supports a complete array of new and existing services across a unified, easy-to-manage infrastructure. And in today’s lean economy, the right solution is the one that offers very low cost of entry yet scales gracefully in services and bandwidth, whenever the business case warrants. Carrier-class Voice and Private Line TDM Services Over a Packet Infrastructure ADC responded to these market requirements by providing a solution that allows packet-based networks to carry both Ethernet and TDM traffic. Our solution bridges the diverse requirements between TDM traffic, with its requirements for timing and synchronization, and packet networking, which tolerates all manner of delay, inconsistency and impairment. The LoopStar 700 product suite uses breakthrough circuit emulation technology to extend carrier-class TDM services over today’s packet networks. The LoopStar 700 delivers traditional T1 (E1 or J1) circuit-based voice/data/video services over Ethernet/IP with the same no compromise quality and robustness as a circuit delivered in native TDM over SONET/SDH. Using this cost-effective device at the carrier edge, one efficient Ethernet/IP network can carry a full range of services to customer locations, such as voice trunks from private branch exchange (PBX) systems and Frame Relay leased lines, alongside Ethernet traffic. SONET/SDH or Optical Ethernet Metro Network Data Video Voice Ethernet TDM TDM PBX LS 700 The LoopStar 700 delivers carrier-class TDM and Ethernet circuits over a carrier-grade packet network 3 / 0 6 • 1 0 2 3 1 6 A E LoopStar ® 700 Circuit Emulation LoopStar ® 700 2 w w w . a d c . c o m • + 1 - 9 5 2 - 9 3 8 - 8 0 8 0 • 1 - 8 0 0 - 3 6 6 - 3 8 9 1 Reduce CAPEX and OPEX While Growing Services and Revenues Converging TDM traffic onto a packet infrastructure provides compelling benefits. It allows enterprise customers to receive a full range of services, whether Ethernet or TDM-based, from one provider, and enjoy the advantages of one monthly bill, attractive service bundles, and a single point of contact for all their communication needs. For metro service providers, the ability to offer premium TDM services over packet networks while also adding new revenues from Ethernet services enhances all facets of the cost/revenue/quality equation. With circuit emulation service on the LoopStar 700 family, providers can: • Attract new customers by offering more services on existing networks. • Increase revenues by extending valued TDM services to areas covered only by packet networks, without having to deploy overlay networks or rely on alternative carriers. • Reduce CAPEX by providing multiple services without multiple networks, devices or links. A single LoopStar 700 can support any combination of Ethernet and TDM bandwidth, up to the payload rate of the uplink. Because all traffic is packetized, there’s no need to aggregate circuit and packet traffic separately, either at the customer edge, in the transport network or back at the central office. Providers can cap investment in expensive TDM edge devices as the transition to cost-effective, multi-service platforms based on IP occurs. • Significantly reduce OPEX by capitalizing on the efficiencies of packet processing, consolidating packet and TDM services over shared links, and provisioning end-to-end services. To provision a T1 circuit, for example, an operator simply specifies the destination IP address and port of the circuit. Unlike TDM systems, there are no intermediate nodes to configure. There also are no SONET ADMs to configure, digital cross-connects to program or wires to cross up. New customers and services can be turned up easily and quickly. Preserve Timing Across Packet Networks The LoopStar 700 products can synchronize the timing of the emulated signal in any of the following ways: • From an external timing source, such as a BITS clock or GPS source. • From a direct incoming link from the central office or Point of Presence (PoP). For example, if the link is a T1 from a digital cross-connect or Class 5 switch, the LoopStar 700 can take the timing from that link. • Using adaptive timing, the timing of the signal is reconstructed based on the average arrival rate of incoming packets carrying TDM traffic. The LoopStar 700 applies a patented adaptive timing technique that uses advanced algorithms to meet circuit jitter specifications – even in the face of high packet delay variation and packet impairments. This flexibility in timing options enable providers to design synchronization solutions that best suit their networks. 3 / 0 6 • 1 0 2 3 1 6 A E LoopStar ® 700 Circuit Emulation LoopStar ® 700 3 w w w . a d c . c o m • + 1 - 9 5 2 - 9 3 8 - 8 0 8 0 • 1 - 8 0 0 - 3 6 6 - 3 8 9 1 Ethernet / IP Network Circuits In (T1, E1, J1) Circuits Out (T1, E1, J1) Transmit Packets Receive Packets LS 700 LS 700 The LoopStar 700 delivers carrier-quality TDM circuits over a packet network Transparently Handle Packet Impairments and Delay Variation The LoopStar 700 has an auto-optimizing jitter buffer that intelligently absorbs packet delay variation, recovers from out-of-order packets, and minimizes the effects of lost packets. As packets are received, the buffer holds them only as long as necessary to smooth out the effects of a packet transport and deliver accurate, ordered TDM bits at consistent intervals. Other vendors use a fixed buffer for this purpose. However with fixed buffers, the size of a buffer must generally be set for anticipated worst-case delay, and all traffic receives the same buffer treatment, regardless of current network performance. When the buffer is set high, packets that arrive with minimal latency and delay variation sit for a long time in the buffer, adding unnecessarily to overall latency. Yet, when a fixed buffer is set too low, it can only correct for small amounts of packet delay variation, and the provider risks disruptions from out-of-spec traffic. Under the best circumstances, a fixed buffer is never optimized; it always adds more latency than necessary. The LoopStar 700 constantly measures packet delay variation (PDV) and automatically resizes the buffer in response to actual traffic conditions: • If the network is efficient (or traffic is local) and packet delay variation is low, the LoopStar 700 reduces the buffer size and minimizes incremental buffer delay. • If the network is inefficient, congested (or traffic traverses long distances or multiple networks), and packet delay variation is high, the LoopStar 700 automatically increases buffer size to absorb the greater variation. This enables the system to continue to deliver bits at the consistent interval required by TDM. These changes in buffer size take place without operator intervention and without affecting transported traffic. Auto-optimizing buffer capability not only enables the system to respond dynamically to network events, it simplifies set-up and installation. There’s no need to calculate or guess possible packet delay variation and pre-configure buffer sizes on all edge devices. Quality of Service (QoS) Required by TDM Traffic The LoopStar 700 uses several mechanisms to provide the QoS required by voice traffic, including marking packets with up to seven levels of priority treatment using 802.1D (p) priority bits. By default, the LoopStar 700 always grants highest priority to circuit emulation traffic. Even if the packet transport network delivers disappointing performance, the LoopStar 700 continues to deliver no compromise circuit emulation service. Robust packet-handling mechanisms ensure that mis-ordered packets are properly reordered, and prevent lost packets from causing frequency errors. The auto-optimizing jitter buffer can accommodate more than 100 milliseconds of packet delay variation (PDV). Since business-class IP networks typically are designed to produce no more than 50 milliseconds of PDV, providers know they can consistently deliver carrier-quality TDM services to their customers. In contrast, some alternative systems can only operate within very small tolerances, leaving the emulated service vulnerable to degradation or disruption. Web Site: www.adc.com From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 • For a listing of ADC’s global sales office locations, please refer to our web site. ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, Minnesota USA 55440-1101 Specifications published here are current as of the date of publication of this document. Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice. At any time, you may verify product specifications by contacting our headquarters office in Minneapolis. ADC Telecommunications, Inc. views its patent portfolio as an important corporate asset and vigorously enforces its patents. Products orfeatures contained herein may be covered by one or more U.S. or foreign patents. An Equal Opportunity Employer 102316AE 4/06 Original © 2006 ADC Telecommunications, Inc. All Rights Reserved ApplicAtion note Boston Metro Atlanta Metro LAN PBX LAN Data PSTN Class 5 Class 5 IP MPLS Core PSTN Switch Switch Router Router LAN PBX LS 700 LS 700 LS 700 LS 700 LS 700 Transport Circuit Emulation Traffic Across a Multi-vendor Network The LoopStar 700 maps circuits to standard IP packets that are carried over standard Ethernet frames, with or without VLAN (Virtual Local Area Network) tags. As a result, circuit emulation traffic generated by the LoopStar 700 can be switched or routed through any vendor’s equipment. The service provider can build a best-of-breed open system with switches, routers and other components from multiple vendors. Leadership in Circuit Emulation Our product design engineers are playing a leadership role in the IETF working group that addresses mapping and transport of non-IP services (such as TDM, SONET, Frame Relay and ATM) over IP and MPLS. This Pseudo-Wire Emulation Edge-to-Edge (PWE3) working group is developing standards that enable services on packet networks to look, feel and perform like dedicated, private circuits. ADC strongly believes that emulated circuits must support the same service quality, testing mechanisms, alarms and alerts found in traditional transport systems. Anything less is unacceptable for today’s competitive metro carrier markets. The LoopStar 700 product suite is optimized to provide this service along with Ethernet services in high-density, metropolitan area networks serving single enterprise customers, multi-tenant units and campus environments. With true, IP-centric circuit emulation, traffic can pass through multiple networks and switches and routers from multiple vendors . 1 - 8 0 0 - 3 6 6 - 3 8 9 1 LoopStar ® 700 Circuit Emulation Technology Extends TDM Services Over Packet Networks Overview Traditional voice and private. PBX LS 700 LS 700 LS 700 LS 700 LS 700 Transport Circuit Emulation Traffic Across a Multi-vendor Network The LoopStar 700 maps circuits to standard IP packets