Converged networks: No longer if, but when

Companies can't pass up compelling benefits such as increased utilization of resources and reduced costs

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As with any architecture, notes Davis at Brocade, there are pros and cons. One possible con of converged networks is the increased complexity of managing multiple traffic types and the service levels for each, compared with a dedicated network model, where sharing is not a consideration. With any architecture that shares resources among multiple functions, the possibility of contention for resources exists. That's why features such as adaptive networking are vital in converged networks, because administrators can set policies and rules for services levels, end to end, through the converged network. This makes management easier while also enforcing the service levels, so users of the network experience the same level of service as if they were on a dedicated infrastructure.

"In addition," says Davis, "while some organizations could consolidate mainframe and open systems connectivity on platforms they already have deployed, they choose to keep these applications separated on dedicated network infrastructure for reasons of business rules, oversight and ownership, and/or organizational preference. Keeping the networks separate means they can maintain proven operational and organizational ownership and processes that would otherwise need to be reengineered in a new model."

"Another potential disadvantage of a converged network is the dependency on a single infrastructure," adds Heath at Extreme Networks. "This makes resiliency and reliability vital. In addition, a modular software operating system is also a key factor because it provides reliability through the separation of processes, hitless software upgrades and the simplicity of the same OS employed across the switching product portfolio, which minimizes human error."

According to Heath, less than 50ms path protection fail-over is a requirement on voice networks, a condition that may not have been imposed on the network before convergence was introduced. The Ethernet Automatic Protection Switching protocols can meet this need to keep a voice call up and active, even in the event of a fiber cut or interruption. Quality-of-service prioritization for data, voice and video also becomes more important.

"It's not a disadvantage," says Mike Babin, assistant director of communications/IT department at Concordia University, "but two areas that still need improvement are teleconferencing and videoconferencing. We use the former for teaching and meetings and the latter for classroom training. Both are extremely difficult to support and require an expert staff on hand to manage and troubleshoot the process. Otherwise, we are quite happy with our converged network."

Concordia University has a standard Cisco architecture core/distribution access layer network on two campuses with 30 buildings per campus. The two cores on each campus are each 6500-class switches, and 4,000 telephone lines (with only 150 leased from the phone company; the rest are VoIP). They have a wireless network with about 360 access points (indoors) and 40 or so for outdoors (60 are 802.11, Draft-2 compliant). "In terms of the network," says Babin, "we currently have the capacity to support any of the converged apps."

Boiling it down

According to Dennis Drogseth, vice president and analyst at Enterprise Management Associates Inc., the volume of traffic over the networks today is predominantly application traffic -- largely Web-based applications, followed by client/server. VoIP is still a relatively small percentage, whereas, for instance, service-oriented architectures are rising. And while voice, streaming media and other technologies appropriately get the concerns of the network community, Web-based applications and Web 2.0, in particular, are increasingly posing a challenge, as the network is becoming virtually a "backplane" for applications.

"Virtualized environments, as the network needs to route between [virtual machines] geographically dispersed in support of a single application, are also going to create challenges to network managers," says Drogseth. "So my point is that the 'converged network' discussion is a bit parochial, focusing on voice, media and data with voice and media getting the limelight when, in reality, the converged network will still be primarily about managing application traffic effectively in an increasingly virtualized universe."

This story, "Converged networks: No longer if, but when" was originally published by CIO.


Copyright © 2008 IDG Communications, Inc.

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