Enforcing Service Level Agreements

Service level management and monitoring are often necessities for providing differentiated services to the users of their hosted applications. ZXTM enables business logic to be applied to traffic management, closely monitoring how services perform against defined SLAs. This delivers rapid assessment of the health of application services, facilitating practical capacity planning.

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What are differentiated Service Level Agreements (SLAs)? 

SLAs are typically defined for a particular service to guarantee performance or availability to end-users. Some services are more critical than others; for example, telecommunication carriers will have very stringent SLAs for their telephony services, but less restrictive SLAs for their corporate web site. Within each service, different groups of customers may have paid a premium for enhanced performance or availability, so there needs to be SLA differentiation at both the service and end-user levels.

Can you give me an example? 

Imagine an Application Service Provider (ASP) offers two services: e-commerce and email hosting. A simple case would be where the ASP offers its gold customers a response time of under two seconds for e-commerce transactions, and under eight seconds for emails to be delivered. In comparison, its silver customers (who pay less) are only guaranteed response times of under four and ten seconds respectively.

What can ZXTM do to help me differentiate my SLAs? 

ZXTM has unique functionality which allows you to define response times for requests to particular services, and within each of those services, to define response times for different groups of customer. When response times fall outside of the parameters dictated by your SLAs, ZXTM will take whatever appropriate custom actions are configured in order to enforce all your differentiated SLAs. These could be simple tasks such as alerting network operations, or more complex tasks such as the automatic provisioning and introduction of additional servers to the cluster.

I run many services; do I have to configure a separate SLA rule for each one? 

No. Just as with TrafficScript™ rules, when you define a service level management rule, it is put into a shared store called the Catalog. This means that you can apply the same rule to as many services as you require.

How can I monitor how my service levels are doing? 

It's easy; just as with every other aspect of ZXTM, you can monitor how well your services are performing against your SLAs both through the web-based graphical user interface, or via an SNMP-capable network monitor such as HP OpenView.

Can I redirect traffic to different server pools using service level information? 

Yes you can. Information relating to the performance of your configured service level monitoring rules can be used in TrafficScript™ rules so you can decide which pool of servers is the best one to use to ensure your SLAs are maintained.

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