The Evolution of Network Monitoring Access

Why service providers must take steps to implement a monitoring strategy that continues monitoring legacy network technologies and establishes the path for converged network monitoring.

by Jesse Price

The majority of the telecom world is in a state of transition from what I will refer to as “the past” to “the future.” While these terms are useful for their brevity, they are, in reality, oversimplifications. The past, composed of legacy networks, is often still the current state of either entire networks or portions of networks. The future, composed of a converged network, sometimes already exists, but is far from pervasive and ranges in the level of “convergence.” It, too, may exist only in certain parts of a carrier’s infrastructure.

In this article, we will discuss the past and the future of networks with respect to network monitoring access, along with the challenges that are encountered during the transition from one state to the other. Finally, an emerging solution to these transition issues will be presented.

The Past: Legacy Networks

In the past, service provider networks consisted of several smaller, legacy networks. Each of these networks was essentially self-sufficient, complete with monitoring tools that were designed to monitor traffic for that specific network technology.

Consider a service provider network comprised of a T-Carrier/PDH network, a local area network (LAN), and a SONET/SDH network. All of these networks have a probe, a traffic analyzer, and an intrusion detection system (IDS) attached to them to monitor their health and provide troubleshooting assistance. Specifically, a traffic analyzer provides real-time visibility into the composition of traffic, a probe monitors bandwidth utilization, and an IDS discovers unusual traffic patterns. Each tool monitors a specific traffic type.

One of the foremost problems with this network architecture is that it is not cost-effective, due in part to the necessary redundancy of its monitoring tools. A SONET/SDH traffic analyzer, for example, can only attach to a SONET/SDH network, a LAN traffic analyzer to a LAN, and so on. This is a frustrating situation because although the three networks are carrying essentially the same services or suite of services, the access network technologies (physical media) are different; consequently, each network technology requires its own dedicated tool.

Compounding the duplicate tools problem is the issue of increasing data rates. As more traffic traverses the network today, core transport speeds are being forced to increase at a rapid pace to transport all of the information. When LAN transport speeds increase from 1GigE to 10GigE, for instance, an expensive LAN probe either needs an overhaul on its interfaces or it is rendered obsolete. Neither option is economically sound as a long-term strategy.

The Future: Converged Networks

The future of networks is the converged network, where legacy networks come together to form a single IP-based network that can carry voice, video, and data traffic. This type of network is preferable to legacy networks for several reasons. First, overhead costs are significantly lower because a single network replaces several networks. Second, the majority of security and monitoring tools are most cost-effective when equipped with Ethernet access ports, so transporting more traffic on Ethernet technology will result in sizable cost savings in the long run. Third, converged networks have greater potential for the development of new revenue-generating opportunities since the groundwork for the applications already exists in a converged network.

Unfortunately, there are a few issues that converged networks do not resolve, such as the issue of increasing data rates. Because network transport technology continues to evolve from 1G to 10G to 40G and beyond, even converged network monitoring tools can be rendered obsolete in a relatively short time span.

The Transition: Leveraging Existing Networks and Tools

The transition from the past to the future state of networks cannot happen overnight because many networks have an extensive number of legacy network tools such as Packet over SONET/SDH (POS) probes and T-Carrier/PDH signaling probes already installed in their architecture. Replacing all of these existing tools with converged tools would be a cost-prohibitive undertaking. Instead, service providers must find a way to leverage the legacy tools and focus budgets on acquiring converged tools for the new services being introduced. In this way, networks will be equipped to access and monitor both past and future network technologies, thereby ensuring a comprehensive monitoring strategy.

Solution: Topology Optimization

The good news is that there is a solution that will not only protect the investments already made in legacy monitoring tools, but will aid in the transition and continued build-up of converged networks. The solution is called topology optimization, or the creation of a common network monitoring topology with a single technology and flexible monitoring tool.

This is accomplished using a class of products called monitoring access optimizers that provide interface translations, filtering, load balancing, and aggregation functions. Monitoring access optimizers enable tool investments to be made in a uniform manner while focusing on next-generation network topologies, thereby eliminating tool redundancies. For example, translating SONET/SDH to Ethernet and T-Carrier/PDH to Ethernet allows a single Ethernet-based IDS to simultaneously attach to three different networks.

Service providers can realize even greater cost savings by choosing the most cost-effective network service available at the time to reduce the operating cost of the network. A 10G monitoring probe, for example, may be less expensive than an OC192/STM-64 monitoring probe. Using a monitoring access optimizer, the 10G probe can now access both 10G and OC192/STM-64 networks from the less-expensive tool by translating the OC192 interfaces to 10G outputs.

Monitoring access optimizers also provide a good solution for handling increasing data rates that occurs in both legacy and converged networks. They can be configured in a one-to-many configuration to access a 10G pipe, for example, and load balance the traffic to multiple 1G outputs. This allows a VoIP probe equipped with 10G ports, for example, to access 40G traffic, thereby extending its usable lifetime.


Nobody can know for certain how long it will take to complete the transition from legacy networks to converged networks, but what is certain is that the migration is evolutionary and not done by ripping and replacing infrastructure.

In the meantime, service providers must take steps to implement a monitoring strategy that continues monitoring legacy network technologies and establishes the path for converged network monitoring. The best approach is to implement topology optimization with monitoring access optimizers.

As vice president of sales and marketing for NetQuest Corp., Jessie Price is responsible for direct and channel sales, strategic partnerships, and marketing initiatives for NetQuest's entire portfolio of monitoring access solutions. You can contact the author at

Must Read Articles