SRV, which is an abbreviation for Service, is a DNS record, which allows you to use a domain name for a particular service different from an Internet site. By creating a few SRV records, you are able to use the domain name with different providers and direct it to several servers simultaneously, every single server managing a different service. You can specify the port number for the connection to each and every machine, so there will not be any interference. You could also set different priorities and weight for 2 records that are used for the very same service, but point to different servers for redundancy or load balancing. Using an SRV record you can use 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 providers. Which one a client of yours is going to use depends on the priority and weight values you have set.