SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain for a specific service different from a site. By setting up a number of SRV records, you will be able to use the domain name with different providers and direct it to many servers at once, each server handling a different service. You are able to specify the port number for the connection to every machine, so there will never be any interference. You could also set different priorities and weight for 2 records which are employed for the very same service, but forward to different servers for redundancy or load balancing. With an SRV record you can use your domain address or a subdomain under it for a Voice-Over-IP server, for instance, and have the actual software running on a number of machines with different companies. Which one a customer of yours is going to use will depend on the priority and weight values which you have set.