Real-time SLA monitoring tools

Network executives who buy corporate Internet services are no longer willing to buy new sight unseen. They want active service-level agreement (SLA) verification to help prove that their provider will deliver the goods. And they want immediate feedback on relative performance metrics to determine if they're getting what they contracted for.

Today's SLA monitoring technology, however, is more likely to report problems after the fact, when it's too late to do anything and nearly impossible to determine the source. Service-level measurement today typically happens at the network's core. But to be credible, service-level performance must be measured from the customer's perspective, where the customer interacts with the network.

Yet true SLA verification is within reach. New classes of hardware, called verifiers, sit at the demarcation point between a customer and service provider - and eliminate the blur that has prevented accurate service measurement by offering the information in real time. This also eliminates the finger-pointing that weakens relationships with service providers.

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How it Works

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Identifying service demarcation points, or demarcs, delineates the "change of control" boundary where a provider's network begins and a customer's network ends.

Enterprise customers simply plug verifiers in-line next to a router or firewall. Verifiers run a real-time operating system and application-specific test modules. For pervasive SLA verification, verifiers must sit in-line without interrupting it, which means a dedicated hardware verifier.

Verifiers time-stamp packets. Active synthetic transaction tests and passive monitoring use the time-stamp engine to maximize test accuracy.

Once hooked up to the Internet, a verifier learns, through an automatic rendezvous protocol, which server to talk with. It downloads its configuration and the tests it will run from that server. When a verifier authenticates with the central reporting software system, the two recognize each other through a unique key assigned specifically to each verifier. Verifiers maintain a secure, encrypted, mutually authenticated connection to the central software system at all times, uploading test results, and downloading configuration updates and new software modules.

A verifier works like a turnstile, recording all network traffic passing through it. Verifiers also mimic a customer's use of a network as they run sophisticated tests of services, such as voice over IP or VPNs, while still collecting precise network statistics. The verifier relays information to the central reporting software that analyzes it, compares it with SLA stipulations and oversees the verifier's operation.

Innovations in software hierarchical design let hundreds of thousands of verifiers be deployed on a network. The software integrates with provisioning, reporting and management systems to report service levels to customers, warn them of network problems and incorporate SLA performance results into billing.

Verifiers sitting in the network contain multiple levels of fail-safe capabilities so they don't impede traffic or disrupt the network should it lose power, for example. Security is also an issue when verifying service from a customer's perspective requires crossing firewalls. While they must be encrypted and authenticated for carrier deployment, verifiers can be designed not to open security holes in the firewalls for some protocols and instead use standard firewall port numbers, such as those for HTTP, which are universally allowed through firewalls to permit Web browsing.

There's no need to add, reconfigure or customize a firewall to support the operation of a verifier.

From security to real-time monitoring, customers today expect providers to verify service levels to the best of the latest technology's ability. A combination of continuous traffic analysis and proactive network testing is the most powerful way to prove service performance. Ultimately, verified service levels build not only trust and happy customers, but also help enterprise customers move to advanced IP services because they're convinced they'll know what they're getting.

Warter is vice president of marketing and business development at Brix Networks. He can be reached at jwarter@brixnet.com.

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09/25/00