SRV, which is an abbreviation for Service, is a DNS record, which permits you to employ a domain for a certain service different from a website. By creating a few SRV records, you are able to use the domain name with different providers and direct it to a number of servers at the same time, every single server handling a separate service. You can specify the port number for the connection to each machine, so there will not be any interference. You can also set different priorities and weight for 2 records that are employed for the exact same service, but point 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 example, and have the real software running on several machines with different companies. Which one a customer of yours is going to use depends on the priority and weight values which you have set.