Databus Issue: 2006 2 05/17/2006
The Emerging “Education-Class Network
Scott Lucas Director of Converged Network SolutionsThe Nerve Center for Communications and Data Across the Campus
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K-12 school district networks are undergoing significant changes. We are witnessing the migration away from best-effort, low bandwidth networks based on frame relay, T1, and 10 megabit Ethernet, to end-to-end Gigabit Ethernet infrastructures that serve a wide spectrum of educational, computing and communication needs.
This article reviews the needs of modern K-12 networks and proposes a set of technologies and implementation tactics that create the Education-Class Network, enabling a dynamic “communication and information access everywhere” infrastructure across school districts and attached facilities.
To achieve the Education-Class Network, the underlying infrastructure must be:
1) Capable of supporting mission-critical connectivity with highly available, fault tolerant, and tested solutions
2) Capable of supporting multiple application types with a rich set of traffic prioritization capabilities
3) Simple to implement and maintain for IT staff
The result is an effective, practical, and future-ready foundation for converged voice and video communications, application transactions, and Internet access.
Designs on Availability
Education networks are evolving to support sophisticated applications and mission-critical communications traffic on a single infrastructure. Extreme Networks envisions a highly-available solution that meets the design, resiliency, and voice-readiness criteria for a modern IP network. In short, a network with reliability comparable to traditional phone systems.
To reach this objective, the converged network architecture should be designed to enhance fault tolerance and make the best use of available bandwidth. By using advanced protocols that maintain connectivity even under catastrophic failure conditions, network designers can meet their user’s expectations for dial-tone availability. Finally, all new network designs should be assessed for voice readiness at each site. Some useful metrics for such an assessment might include application traffic base lining, measurement of available bandwidth on given links, and an estimate of the potential growth in outgoing communications traffic.
Increasingly, highly-available Ethernet networks are adopting techniques and technologies from the service provider market. For example, SONET-like dual ring network topologies, built using 10 Gigabit and Gigabit core switches, can deliver redundant fiber links for low-latency fault recovery and bandwidth allocation when and where it is needed.
Compared to other network designs, the ring topology allows more nodes to be connected with less complexity because data between end points traverses fewer paths. As a result, ring designs can effectively cover a larger geographic location. Ethernet rings compare favorably to star or “hub and spoke” topologies that require more fiber connections for the same result, adding more equipment and cost.
To fortify these links and assure network performance, new fast-failover protocols have been introduced that match the stability of SONET technologies, with failure recovery times of less than 200 milliseconds (below one second).
The Ethernet Automatic Protection Switching (EAPS) protocol is one of the best examples of a ring protection technology that delivers an Ethernet infrastructure suitable for reliable voice. Submitted to the IETF by Extreme Networks as RFC #3619, EAPS allows a master switch to continually monitor link availability throughout the Ethernet ring. Should a connection become cut or interrupted, EAPS can quickly redirect traffic between switches. Incredibly, EAPS has been proven repeatedly to fail over in less than 50 milliseconds with no packet loss. This allows voice conversations to progress without the user ever realizing a network failure occurred.
Aligning Traffic Priority for Convergence
A network should be ready and able to handle diverse types of traffic without the costly and wasteful over allocation of network bandwidth across links. Extreme Networks has pioneered end-to-end traffic prioritization with a powerful set of Quality of Service (QoS) capabilities. In K-12 environments, QoS is a cornerstone technology when data, web, voice, and video traffic are transported on an Ethernet infrastructure.
QoS should be both network wide and simple to implement. While IT managers have historically complained about the complexity of managing QoS, networks are now at the point where they can be set up by default to have all switches automatically recognize voice or video packets and assign the correct priority to each type of traffic for higher overall service levels.
QoS becomes even more critical as voice proliferates on the converged network. At network traffic aggregation points, the risk of congestion and degraded voice quality can be minimized by increasing the bandwidth and switching capacity on these network links to handle traffic spikes. And, as voice traffic becomes prevalent, organizations may wish to consider establishing multiple levels of voice priority so critical users, locations, or devices can enjoy higher priority over normal voice traffic.
Keeping it Simple
Communications and networking remains a dynamic field. Unfortunately, simplicity is a critical and often compromised requirement. Extreme Networks believes that the simplicity of equipment, management, and configuration is an essential component for the Education-Class Network.
Today, network managers are embracing management tools and systems that go beyond command line interfaces, basic equipment health checks, and box-by-box configurations. Complexity is often driven by the diversity of devices, such as IP phones, at the network edge. Solutions that can detect a wide variety of devices using standards-based technologies, such as the Link Layer Discovery Protocol (LLDP), can significantly ease the burden of managing large, converged networks.
Security is another crucial concern for the Education-Class Network. Security capabilities that work in concert with the network infrastructure to detect and mitigate threats are the best approach to the threats faced by K-12 network managers. Networks are safer and more available when they can work closely with security solutions to offer meaningful insights and unprecedented control.
A good example of how the network can interact effectively with a security solution is the combination of Extreme Networks’ CLEAR-Flow security rules engine and the Sentriant security appliance. With CLEAR-Flow, critical network switches can monitor all traffic at wire speed and mirror suspicious traffic to the Sentriant appliance. If Sentriant detects a rapidly-propagating threat, the appliance can assert control over the switch to rate limit, contain, or block traffic. And, since the appliance is not directly in the traffic path, denial of service outages due to overwhelmed security resources is no longer a concern.
Conclusion
The Education-Class Network, with a focus on fault tolerant design, availability, prioritization, and ease-of-management can be a reality with proper planning, use of standards-based technologies and the disciplines as outlined above. The tremendous benefits to students, faculty, and greater society will become clear as information and communication live together seamlessly.
Scott Lucas, director of converged network solutions, Extreme Networks, Inc., can be reached at slucas@extremenetworks.com. Visit http://www.extremenetworks.com.
