SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain name for a specific service different from a site. By setting up a number of SRV records, you’ll be able to use the domain with different providers and direct it to many servers simultaneously, each and every server handling a separate service. You'll be able to specify the port number for the connection to every single machine, so there will not be any interference. You could also set individual priorities and weight for 2 records that are employed for the same service, but point to different servers for redundancy or load balancing. Using 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 specific software running on a number of machines with different providers. Which one a client of yours is going to use is determined by the priority and weight values which you have set.