SRV, which is an abbreviation for Service, is a DNS record, which permits you to use a domain name for a particular service different from a site. By setting up a number of SRV records, you’ll be able to use the domain address with different providers and direct it to several servers simultaneously, each and every server managing a different service. You'll be able to 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 two records which are used for the same service, but point to different servers for redundancy or load balancing. By having an SRV record you can use your domain 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 companies. Which one a customer of yours is going to use is determined by the priority and weight values you have set.