Transitioning to next-generation (NG) technologies and a converged network infrastructure generates new challenges to all involved. In addition to the normal concerns about maintaining SLA-defined levels of availability, operators now must also deal with issues caused by the multiservice and multitechnology environment.
In the new NG multitechnology network environments, the design and optimization required to meet emerging subscriber demands are increasing operational complexity to levels never before encountered by telecom operators.
Multitechnology environments also bring multiple protection and restoration techniques (MPLS FRR, G-MPLS ASON, SDH SNCP, DWDM fast switching etc.). There are many cases in which restoration methods overlap each other, creating higher-than-needed reliability with needless CAPEX and network resource usage.
In other cases, services might be protected by two different techniques, creating competition between the two methods and a failure of the service, although it is protected. Automated planning tools have proven to be the solution for this challenge.
Dealing with nextgen network challenges
Today, there are several methods for protecting network services. Each technique differs mainly in the response time for any failure and the network resources allocated per protected service. Because some protection techniques are dynamic and statistical, operators struggle to spot the restoration paths per service and whether two protection techniques overlap one another.
As operators design their network protection schemes, they face dilemmas both in the business and the technological aspects of the process. Some of the dilemmas that arise include the following:
1) How do I optimize my network resources while protecting and increasing reliability of the network services?2) How can I assure the QoS and uptime committed to customers? 3) What is the optimized restoration technique for each region in the network?4) Are there any services that are protected by more than one technique, creating CAPEX waste?5) How do I measure the level of protection in the network?6) Faced with these dilemmas, how can NG automated planning tools help?
In recent years, transport network planning tools have played a key role in helping operators achieve their desired performance and reliability/QoS requirements.
By automatically analyzing and highlighting network weaknesses, and providing solutions for network optimization, planning tools have increased system efficiency and simultaneously reduced operating expenses. In fact, almost all planning tool capabilities save both time and money, and reduce capital expenditure (CAPEX) and operating expenses (OPEX) in a variety of ways.
However, in an NG environment that simultaneously employs multiple recovery methods, traditional planning tools are not sufficient. Full restoration optimization can be achieved only by deploying NG planning tools, which deliver: unified multi-layer analysis; support for all technologies; and support for all restoration methods.
Such a unified system, although complex behind the scenes, should provide an intuitive, 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 an NG planning tool look like for the network operator? Which major modules and features should NG operators look for? The following areas are key:
Multilayer, multitechnology support . To reduce costs, planning tools must analyze network reliability and performance of all levels and transport technologies, supporting the physical layer of fi- bers, ROADM protection, DWDM, SDH (with SNCP protection), GMPLS, ATM and carrier Ethernet using a single tool and a single GUI. It should be an easy-to-use piece of software, bringing the best resource utilization.
For example, planning protection of both SDH and Carrier Ethernet (Figure 1 below ) with a single tool can improve utilization of each optical wavelength, and can also increase the level of Ethernet reliability by planning and analyzing the optical restoration schemes.
|Figure 1: Planning protection of both SDH and Carrier Ethernet with a single tool can improve utilization of each optical wavelength.|
Universal support for all types of networks, network equipmen . Regardless of type and supplier, a the entire inventory into account, enabling progressive restoration paths, optimization of the installed base and reducing the need for additional systems, interfaces or both for protection needs.
Automatic implementation . Restoration optimization results should be automatically integrated into the management system, saving valuable time and effort traditionally spent on manual implementation and maintaining realtime reliability and QoS. Automatic provisioning should take place for all technologies, regardless of vendor or product type.
Synchronized, scheduled work order Implementation . As networks become multilayered and multivendor, provisioning of the desired protection scheme requires, in many cases, updates of several management systems. Planning tools should be able to provision the service in all relevant 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 provisions the Ethernet service that uses the optical layer.
Sublayer analysis (layering, partitioning) . Many network bottlenecks and single points of failure 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.
|Figure 2: A fiber network planning example.|
The impact A recent analysis of a Tier-1 operator's infrastructure, using NG planning tools, shows impressive results. With over 730 network elements and 15,000 different services, the operator's network is based on multivendor platforms, and consists of Ethernet, SDH and DWDM technologies (Figure 2 above and Figure 3 below ).
The network uses several protection methods attached to SDH, MPLS and DWDM. Implementing the NG planning tools concept outlined above, the operator was able to reduce network protection costs and improve network reliability by reducing the number of single points of failure.
|Figure 3: An Ethernet network planning example.|
NG planning tools also optimized restoration paths (for both MPLS FRR and SDH SNCP) and minimized the number of hopsper- service by 30 percent, as well as reducing bandwidth utilization. NG planning tools enabled the operator to expand up to 50 percent without adding platforms or CAPEX in the network.
Looking at the network vulnerability, the planning tools decreased the number of single points of failure (where both the primary and the protected service go through a shared link) along the network, by 80 percent.
In an NG network environment, traditional planning tools are no longer up to the task. However, as you can see from the real-life scenario, NG design and planning tools in your NG network strategy are critical to your network reliability, QoS, CAPEX reduction, expansion and a smooth NG transition.
Ronen Mikdashi is Associate VP of Product Marketing at ECI Telecom .