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