Migrating from Legacy TDM Networks to the Cisco Transport Network Modernization Solution

Some of our recent blog posts, A Requirements Checklist for the Next Generation Transport Network and The Next-Generation Transport Network: Solution Options discussed the business requirements you should consider before selecting a modernization solution and the technology options currently available to modernize aging transport networks. In the post, we’ll delve into the Cisco solution and how it can be used to provide TDM services as well as modernize a number of different network architectures, including: Legacy TDM networks (with DCS and ADM equipment), SONET ADM ring networks, IP core networks (support for TDM services) and a complete central office modernization project.

Cisco Transport Network Modernization Solution

Using high-density circuit emulation (CEM) technology, TDM services can be migrated across an asynchronous IP/Multiprotocol Label Switching (MPLS) network with no errors and a constant delay. CEM provides the ability to terminate TDM traffic over SONET/SDH as an interface, continuing fault propagation between SONET/SDH and the IP/MPLS network using pseudowires running over dynamic label-switched paths (LSPs). LSPs are paths through MPLS networks set up by a signaling protocol. The CEM solution is supported by multiple industry standards and deployed through control planes for both SONET/SDH and IP/MPLS.

You get SONET/SDH-like features, such as OAM and manageability while IP/MPLS and other technologies help eliminate errors and latency. It’s predictable and deterministic, with sub-50ms resiliency. It’s also invisible to end customers, with no new CPE required. Packet optical technology with high-density CEM is a future-ready transport network architecture because it lets you evolve towards metro Ethernet, Layer 3 VPN, and full IP transport whenever you – or your customer are ready.

The Cisco solution includes these software and hardware components:

Cisco Network Convergence System (NCS) 4200 Series
Addressing the inefficiencies at the network edge, this transport system utilizes high-density CEM technology to convert TDM services into pseudowires, which then facilitate the transport of TDM services over a scalable MPLS core network. With this technology, service providers can keep their existing operational models and service revenue while running all their services over an IP network.

Cisco NCS 2000 Series
With its flex-spectrum ROADM, the Cisco NCS 2000 sets the industry benchmark for DWDM solutions. It delivers the touchless programmability, massive scale, and flexibility required to optimize both metro and ultra-long-haul performance.

Cisco NCS 4000 Series Converged Optical Service Platform
The Cisco NCS 4000 anchors a converged packet optical infrastructure by providing DWDM, OTN, MPLS-TP, Carrier Ethernet, and IP multiservice capabilities.

The Cisco EPN Manager Chassis View

Cisco Evolved Programmable Network Manager (EPN-M)
Cisco EPN Manager enables service providers to modernize circuit transport and private line networks by addressing the combination of CEM over packet, OTN, and DWDM/ROADM networks with comprehensive end-to-end network management support.This all-in-one, next-generation product provides device management, network provisioning, and network assurance across converged packet-optical networks.

How it Works: Migrating Different Architectures

The Cisco solution can be used to migrate these architectures.

Legacy DCS and ADM Retirement
The NCS 4200 replaces the functionality of DCS and ADM components. You get a non-blocking, protocol-independent fabric architecture and boundless scale through the use of high-density CEM over a protected Flex LSP core. The power and space requirements of the DCS are cut by nearly 90 percent based on the small footprint required for the NCS 4200. You benefit from significant space, power, and cooling savings. This architecture integrates into both TDM and MPLS packet core networks.

SONET ADM Ring Overlay/Migration
The NCS 4200 and NCS 2000 replace the aging SONET ring as an overlay with a low-cost packet ROADM architecture. With the NCS 2000, DWDM is used to mitigate the need for a second fiber pair. The low cost of DWDM modules combined with state-of-the-art packet switching provides complete flexibility for service delivery. This new architecture provides any-to-any capability, as well as full hierarchical quality of service (QoS), and throughput control (for example, oversubscription). In addition, there is no time slot bounding through the transport path – you use an already lit fiber path, if required.

Example of a SONET ADM Ring Overlay Migration

CEM + Carrier Ethernet Over Existing IP Core Network
NCS 4000 and NCS 4200 transport hardware can be added at the edge to provide CEM services across the MPLS core. This lets you transport any service from one location to another. As a purpose-built solution that supports high-density TDM and Carrier Ethernet, it provides any-to-any-connectivity using a packet-switched network not bounded by TDM transport inefficiencies. You utilize existing equipment in the IP/MPLS core to gain unbounded scale utilizing MPLS/Flex LSP versus less efficient packet transport mechanisms.

Complete Central Office Modernization A to Z
The NCS 2000 and NCS 4000 are deployed to provide colorless, contentionless, omnidirectional, and Flex Spectrum (CCOFS) ROADM technology, OTN, and MPLS capabilities. After the metro core is established to provide high-capacity OTN and Ethernet switching and a 100G colorless, directionless, and contentionless (CDC) ROADM intelligent photonic layer, the metro access, aggregation, and satellite network segments are added. All links are MPLS enabled, and associated LSPs are used to transport the NCS 4200 pseudowires from A to Z. Cisco EPN Manager provides a multilayer view of the network using a single tool. You can eliminate the aging, limited, and static operations systems modifications for the integration of network elements (OSMINE) for alarming and provisioning, which is unable to recognize or manage advanced hardware functionality. EPN Manager provides all the functionality you need end to end, including managing CDC ROADMs.

A Roadmap for Transport Network Modernization

In our E-Book, A Roadmap for Transport Network Modernization, we cover network migrations in more detail. In addition, we look at both the business and technology requirements of transport networks today and into the next decade. The E-Book concludes with an explanation of how our next-generation approach, using Cisco’s high-density circuit-emulation (CEM) technology, provides you with a cost-effective network modernization path, while still supporting ongoing TDM services requirements.

Are you ready to modernize your network? Find out how with A Roadmap for Transport Network Modernization. Download your copy today. Or for a live demo, visit us at Booth #1501 at the OFC Conference in Los Angeles, March 20-23.

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