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 site. By setting up a few SRV records, you can use the domain address with different companies and forward it to numerous servers at a time, every single server managing a different service. You'll be able to specify the port number for the connection to every machine, so there will not be any interference. You could also set individual priorities and weight for two records that are used for the exact same service, but point to different servers for redundancy or load balancing. By having an SRV record you can use your domain or a subdomain under it for a Voice-Over-IP server, for example, and have the specific software running on various machines with different providers. Which one a client of yours will use depends on the priority and weight values you have set.