SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain for a certain service different from an Internet site. By setting up a couple of SRV records, you can use the domain with different companies and forward it to several servers at once, each and every server managing a different service. You could specify the port number for the connection to each and every machine, so there will not be any interference. You can also set individual priorities and weight for two records that are employed for the same service, but forward to different servers for redundancy or load balancing. By having an SRV record you can use your domain address or a subdomain under it for a Voice-Over-IP server, for instance, and have the specific software running on a number of machines with different providers. Which one a client of yours is going to use will depend on the priority and weight values that you have set.