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 few SRV records, you’re able to use the domain with different providers and point it to a number of servers at once, each server managing a separate service. You could specify the port number for the connection to every machine, so there will not be any interference. You can also set different priorities and weight for 2 records which are used for the exact same service, but point to different servers for redundancy or load balancing. With an SRV record you can employ your domain name or a subdomain under it for a Voice-Over-IP server, for example, and have the real software running on several machines with different providers. Which one a customer of yours is going to use will depend on the priority and weight values you have set.