SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain name for a specific service different from an Internet site. By setting up a few SRV records, you can use the domain with different providers and point it to a number of servers at a time, each and every server handling a different service. You could specify the port number for the connection to each and every machine, so there won't be any interference. You may as well set individual priorities and weight for 2 records that are used for the very same service, but forward to different servers for redundancy or load balancing. Using an SRV record you can use your domain or a subdomain under it for a Voice-Over-IP server, for instance, and have the actual software running on a number of machines with different providers. Which one a client of yours will use is determined by the priority and weight values that you've set.