SRV, which is an abbreviation for Service, is a DNS record, which enables you to use a domain for a certain service different from an Internet site. By setting up a number of SRV records, you will be able to use the domain name with different providers and point it to a number of servers at a time, each and every server handling a different service. You'll be able to specify the port number for the connection to each and every machine, so there will never be any interference. You may as well set different priorities and weight for two records which are used for the same service, but forward to different servers for redundancy or load balancing. By having an SRV record you can employ your domain name or a subdomain under it for a Voice-Over-IP server, for instance, and have the actual software running on various machines with different companies. Which one a customer of yours is going to use depends on the priority and weight values that you've set.