SRV, which is an abbreviation for Service, is a DNS record, which permits you to use a domain for a specific service different from an Internet site. By setting up a few SRV records, you will be able to use the domain name with different providers and point it to a number of servers at the same time, every single 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 could also set different priorities and weight for 2 records that are used for the same service, but point to different servers for redundancy or load balancing. By having an SRV record you can employ your domain address or a subdomain under it for a Voice-Over-IP server, for instance, and have the real software running on various machines with different providers. Which one a customer of yours will use is determined by the priority and weight values that you have set.