SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain for a particular service different from a site. By creating a few SRV records, you’re able to use the domain address with different providers and point it to a number of servers simultaneously, every single server managing a separate service. You could specify the port number for the connection to each machine, so there won't be any interference. You could also set individual priorities and weight for 2 records that are employed for the very same service, but direct to different servers for redundancy or load balancing. With an SRV record you can use your domain or a subdomain under it for a Voice-Over-IP server, for example, and have the actual software running on various machines with different companies. Which one a customer of yours is going to use is determined by the priority and weight values that you have set.