Intelligent Service Verificator (ISV)

The Intelligent Service Verificator (ISV) service is the perfect complement to the Intelligent DNS (IDNS) module. ISVs monitor servers/applications availability to automatically update the resource records (RRA) in the IDNS module to ensure that the answers to DNS requests are operational.

For example, if you have two web servers providing the same content, you could load balance the charge between your multiple links and between you multiple servers at the same time, on top of the load balancing the ISVs will permit failover between your multiple servers in case one of them stops answering to the ISV tests.

An ISV can perform two kind of tests, a layer 7 (L7) exchange or a layer 4 (L4) connection. The difference between those tests is that a L7 exchange will replicate a real user request for a web page (for example), get the result from a web server and locate a keyword in the returned page to confirm that everything is in order. A L4 connection on the other hand will attempt to connect to the defined service on the specified TCP port and if the connection is successful the service is considered to be available.

Intelligent Service Verificator service is available on LB1000 and higher models. It is also supported with the GeoLink option for geographic link load balancing.