In support of the effort, equipment providers are spending a significant amount of resources, energy, and R&D time developing comprehensive solutions that will handle the migration efficiently. Consequently, network planning tools are emerging as a core elements of any truly efficient migration strategy.

Advanced Planning
In recent years, transport network planning tools played a key role in helping operators achieve their desired performance. By automatically analyzing and highlighting network weaknesses, and providing solutions for network optimization, planning tools have increased system efficiency and simultaneously reduced operating expense. In fact, almost all planning tool functional capabilities save both time and money, and reduce capital expenditure (CAPEX) and operating expenses (OPEX) in a variety of ways.

Most planning tools available in the market today consist of several core features and capabilities, such as traffic analysis, bill of material reports and network growth simulation. However, not all are built the same; true value-added and competitive advantage for operators are found in Next Generation (NG) Planning Tools. These tools represent an evolutionary approach to planning given that the tools are built and designed to answer the challenges unique to NG telecom operators, or those migrating legacy networks to provide IP-based services, whether fixed or mobile. In theory and in practice, planning tools should be designed to support growing network complexity and perform such tasks as analyze the multi-technology infrastructure and adapt to ever changing service needs (NG voice, VoD, etc.). But that is not the case.

Instead, legacy-planning tools are retrofitted into NG network architectures. Most NG operators are struggling to truly appreciate the complexity involved in migrating an existing infrastructure and skill set to NG networks, and fail to identify the right support tools for this crucial evolution.

The 'Why' of Planning Tools
There are five key requirements that drive operators to implement planning tools. A close look at these will help us understand how such tools should be developed:

1. Network Agility--Service providers must develop methods for reducing service provisioning time. Also, any needed change or planning in the network (long term, mid-term and short-term) must be simplified.
2. End-to-End Design--Operators are evolving toward converged all-IP transport networks. Today, a single infrastructure built by several equipment suppliers supports all required technologies (TDM, Ethernet, WDM) and all services (IPTV, VoIP, PSTN, storage, etc.), producing many benefits. At the same time, this process adds significant complexity to the planning and provisioning procedure. Operators will appreciate automated tools that will enable them to simplify the multi-layered and cross-vendor implementation.
3. Reduced Operational Expenditure--For years, reducing OPEX has remained a major goal for service providers. OPEX can be reduced further by performing auto-provisioning of any re-design along the network and by performing Single Point of Failure (SPOF) elimination that will increase the network's reliability.
4. Reduced Capital Expenditure--NG networks are built with a goal of minimal investment-per-growth. A planning tool that intelligently designs the network to operate in a steady-state and not in extreme capacity conditions will minimize the investment for every change to the network or for new added services.
5. Smooth Migration to Next Generation Infrastructure--Globally, most carrier networks are in the process of transforming into NG networks. For example, mobile operators are moving toward becoming 3G/WiMAX-based networks while wireline service providers are transforming into triple-play operators. Performing such a dramatic transformation in a gradual fashion as dictated by customer demand, without service interruption can dramatically reduce CAPEX investment and still provide operators with a leading-edge competitive advantage.

Putting the 'Next-Gen' in Planning Tools
There are various planning tool modules on the market, each bringing a specific benefit to customers and serving a specific phase of a network's life cycle. To achieve optimal performance and benefit, the implementation of NG planning tools should take place via a single multi-layer platform, supporting all technologies and all stages along the network's evolution.

Such a unified system, although complex behind the scenes, should hit the market with a user-friendly GUI and simplifying features, such as back-tracking of all planning stages. NG planning tools, which will be crucial for the life cycle changes of any network, must analyze both the "high level" cost efficiency perspective for financial managers, and the technical deep-level analysis for network and system engineers.

Unlike traditional planning tools, NG planning tools must support both reactive and proactive planning. Reactive planning is mainly used for immediate response, analyzing the effect of any failure on network performance. The proactive approach optimizes network resources for the long term, while suggesting improvements in the steady state and the day-by-day work.

So what should a NG planning tool look like for the network operator? Which major modules and features should NG operators look for? The following areas are key:

• Multi-layer, Multi-technology Support--To reduce costs, planning tools must analyze network performance at all levels and transport technologies, supporting the physical layer of fibers, ROADM, DWDM, SDH, ATM and carrier Ethernet under a single tool and a single GUI. It will be an easy-to"use piece of software, bringing the best resource utilization (See Figure 1). For example, planning both optics and Carrier Ethernet with a single tool can improve utilization of each optical wavelength (benefit #1), but can also increase the level of Ethernet reliability (benefit #2) by planning and analyzing the optical restoration schemes.

Figure 1. Multi-Layer Planning
• Optimal and Step-by-Step Efficient Planning--during network expansion or transition to NG networks providers must leverage existing infrastructure, thereby reducing total cost of ownership (TCO). A recent analysis of a mobile customer's network has shown that pre-planning the step-by-step transformation dramatically reduces costs. As a result, ROI period had shortened to 50% as compared to a non-pre-planned transformation.
• Universal Support for All Types of Networks and Network Equipment--Regardless of type and supplier, a chosen planning tool should take the entire inventory into account, enabling maximum optimization of the installed base and reducing the need for additional systems and/or interfaces.
• Automatic Implementation--The planning optimization results should be automatically integrated into the management system, saving valuable time and effort traditionally spent on manual implementation. Automatic provisioning should take place for all technologies, regardless of vendor/product type.
• Synchronized and Scheduled Work Order Implementation--As networks become multi-layered and multi-vendor, provisioning of new services requires updates of several management systems. Planning tools should be able to provision the service in all involved management systems, as well as synchronize the different tasks. For example, an Ethernet service that is transported over WDM wavelength should have a planning tool that first provisions the WDM layer by negotiating with the optical management system, and only after that should provision the Ethernet service that rides over the optical layer.
• Sub-Layer Analysis (Layering & Partitioning)--Many network bottlenecks are caused by local inefficiency. To find the exact point of inefficiency, a planning tool should be able to derive and analyze any sub-layer/partition of the network. This capability dramatically improves analysis accuracy and reduces total costs. Moreover, in many cases, different network segments are affected by different constraints and operational environments. Therefore, sub-layer analysis is the only way to achieve realistic results.
• Optimized Tool for All Planning Needs--Strategic, long term, tactical (mid-term needs) and operational (immediate failure analysis and recovery planning)--Advanced planning analysis and optimization features include both current and predictive analysis, which both significantly enhance network performance and QoS. Having a single platform that analyzes both current and predictive infrastructure can optimize capital investments, because every stage of the short-term design is planned as a part of, and with a focus on the long term design. "Current analysis" examines traffic protection validity and single point of failure, where the system verifies if protection is both resilient and reliable. "Predictive analysis" includes both failure simulation and network growth analysis.

So What Is The Impact? A Case Analysis
A recent analysis of a Tier-1 operator's infrastructure, using NG planning tools, has shown impressive results. With over 730 network elements and 15,000 different services, the operator's network is based on multi-vendor platforms, and consists of Ethernet, SDH and DWDM technologies (see Figure 2). The network has reached its expansion limits with over 80% on average utilization per link and almost no capabilities to expand.

Implementing the NG planning tools concept outlined in this article, the operator was able to reduce network expansion costs dramatically and improve network reliability by reducing the number of single points of failure.

NG Planning Tools also have optimized restoration paths (for both MPLS FRR, and SDH SNCP), and have minimized the number of hops-per-service by 30 percent, as well as reducing bandwidth utilization. The NG planning tools have enabled the operator to expand up to 50 percent without any addition of platforms or CAPEX into the network.

Looking at the network vulnerability, the planning tools have decreased the amount of single points of failure (where both the primary and the protected service go through a shared link) along the network, by 80 percent.

Moreover, as the SDH layer was optimized, it affected the DWDM layer as well. The two layers were provided from different vendors. Having a multi-layer tool enabled our network engineers to optimize the network in all layers regardless of product supplier.

NG Planning Tools--The Next Coming Attraction
In these challenging economic times, network operators cannot justify spending on incremental network upgrades. The money they spend must result in a dramatic increase in the efficiency of their networks, as well as providing a basis for offering next-generation services in a way that will improve both the top and bottom lines.

While it is clear that the evolution and migration of traditional networks to NG networks is crucial to the telecom industry's future, that migration is not the only issue that must be addressed. For a network operator to truly reap all the rewards of this migration, the network must be planned in the most efficient manner, both for the short-term and the long-term. This means that planning tools focused strictly on next-generation networking must be developed. Retrofitting existing planning tools will not give operators the ROI required in today's difficult environment.

The good news is that such NG planning pools are available today. But even more important is the degree to which these planning tools are answering the evolving requirements of the operators. As demonstrated in the above case, if this can be accomplished, the financial benefit to the operator, and ultimately, the entire industry, will be significant.

About the Authors
Lior Tourgeman is a Senior Product Manager Planning and Optimization Tools at ECI Telecom. Lior can be reached at: Lior.tourgeman@ecitele.com.
Ronen Mikdashi is a Senior Product Marketing Manager in the Network Solutions Division at ECI Telecom. He can be reached at: Ronen.Mikdashi@ecitele.com