Resilient network services essential for real-time success

Reconfiguring switches for resilient services will not only help the network work better now, but will prepare a business for the fast-approaching future of communications.

It's time network managers clean out their closets to prepare for the new model of LAN communications.

Equipment vendors and their customers designed the previous generation of data networks on a client-server model. It is a hierarchical model, with clients making requests to centrally located servers. Traffic patterns adhere to a flow of less traffic at the edge of the network (near end-user devices such as desktops, laptops, PDAs, etc.) to more dense traffic in the core, or backbone, of the network, where aggregations of servers and data storage reside.

Other historical factors have shaped network designs. Most importantly, organizations have focused on building their networks to support data applications that can function perfectly well with small delays. This model has called for the most valuable network services, such as security, quality of service (QoS), bandwidth management, and high availability, to be concentrated closer to data center servers.

This approach to network design has certainly been appropriate and highly successful, but as is becoming clear, the client-server model is now facing challenges it simply was not designed to address. Most significantly, real-time applications are becoming widely popular. "Real time" simply means that -- unlike e-mail or a database query -- communications happen, or need to happen, instantaneously for the applications to function properly. The most obvious example of this is voice over IP, or VoIP. Many companies are switching to this new technology for their office phones. And virtually any company that hasn't will do so when the time comes to replace their existing analog PBX systems.

But VoIP is just the beginning of the real-time communications now converging onto IP networks. Many corporations are making good use of instant messaging, for example, and IP-based desktop video is looking increasingly viable as an alternative to expensive proprietary videoconferencing systems. Real-time demands on the network will only increase as their intrinsic benefits for virtual collaboration drive adoption.

Along with the growth of real-time communications over business LANs, an increasing number of applications follow "any-to-any" traffic flows that operate with little or no assistance from centralized servers. This means the network is no longer following a "to the sea" downhill path of smaller network access points flowing into main stem backbones connecting to data centers. Instead, access devices using such applications as Web-based collaboration meeting tools are talking directly to other devices and skipping the data center altogether.

Current networks were not optimized to manage such real-time, any-to-any communications. A new network model is needed to make the most of converged network communications. Organizations must now consider their network's access layer, the equipment in the humble wiring closet, as strategic as their core backbone. As network managers look to provide consistent services throughout the network for real-time communications, the same principles for the core and distribution layers must be extended to the wiring closet. One such principle is using routing capabilities to provide the requisite control and protection for efficiently managing both traditional client-server data applications and the new host of real-time multimedia applications.

Advanced wiring-closet switches bring with them the benefits of traffic engineering: load balancing, fast recovery, scalability, QoS, multicasting, and bandwidth management. More intelligent switches capable of supporting such services make possible a "dial tone" level of reliability, the 99.999% of uptime benchmark of public phone systems. Such advanced switches, for example, can execute a recovery of less than 200 milliseconds from a failure in the network. That's basically fast enough to make such a glitch undetectable to a user. This provides users that same dependability for other critical communications, including IP telephony and videoconferencing, not to mention making all data applications work that much better.

Resilient services in the wiring closet also boost security, as the wiring closet has become the front line of defense to prevent attacks and help ensure the health of the entire network. Intelligent switches are the first step in controlling the traffic flowing from end-user devices onto the LAN. Until recently, the LAN was assumed to be private and, therefore, secure. With the advent of increasingly sophisticated worms and viruses that spread in a matter of minutes, those policies need to change. New, "real time" users are increasingly mobile and subject to catching viruses and other malware at home, through Wi-Fi hot spots, or at customer and partner sites. Enforcing security at the first point of network contact prevents malicious software from spreading internally behind firewalls and intrusion-detection systems. Wiring-closet switches are becoming key participants in the security effort, and selecting a switch from a vendor with a strong network access control (NAC) security framework is essential to both optimizing network investments and improving an organization's security posture.

The implementation of resilient services also streamlines operations. Resilient access switches will likely use the same operating systems, protocols, and management tools as their full-fledged core switch cousins in other parts of the network. This reduces training needs by consolidating the basic network infrastructure into one language.

Modern enterprise switches now support resilient services capabilities, and many organizations already have these switches in their wiring closets. They simply haven't turned on their resilient services capabilities. After all, they may have never needed such functionality before. And those modular switches that don't have full resilience capability often require only modular component upgrades rather than a trip to the trash can. Switches that don't provide any options for resilient services are likely very long in the tooth and are prime candidates for a refresh cycle.

So the good news is that organizations can move to the new model of converged LAN networks without breaking the bank. But simply upgrading the wiring closet will not adequately address the new demands for real-time networking. The key to success is a proper design of the LAN campus network.

Any such redesign should begin with a thorough audit of the existing network infrastructure. It is during this stage that network administrators can assess what kind of upgrades (software, modular component, or whole unit) they will need in order to bring resilient services to their wiring-closet switches. Once the network is carefully mapped, organizations can draw up a design that suits their needs, both now and in the future.

In order to get network managers started in their journey to implement resilient services in their network, specialized network and systems integrators can assist in drawing a network profile and offer advice on how organizations should redesign their network for this new real-time communications model. Network managers then have the information they need on training, configuration, and operating procedures to help people be more productive. And network designers receive the hardware and software information they need to plan for efficient upgrades and provisioning.

Businesses have made a significant investment in their network, and it's time they got the most out of that investment. A network profile helps to ensure a better return on network investment by laying a solid foundation for more effective long-term planning -- and by creating an environment for rapid response. The benefits include better business continuance planning, business agility, and simplified operations.

The integration of resilient services has become so critical that even if an organization presently uses few real-time applications, it will almost assuredly use them in the future. Reconfiguring existing wiring-closet switches capable of delivering resilient services at the edge of the network will not only help the network work better now, but will prepare a business for the fast-approaching future of communications.

Fred Weiller is Senior Manager, Network Systems Marketing at Cisco Systems Inc.

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This was last published in June 2006

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