SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain for a specific service different from an Internet site. By setting up a couple of SRV records, you’ll be able to use the domain name with different companies and point it to many servers at once, every single 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 may as well set different priorities and weight for two records that are employed for the same service, but point to different servers for redundancy or load balancing. By having an SRV record you can use your domain name or a subdomain under it for a Voice-Over-IP server, for example, and have the actual software running on a number of machines with different companies. Which one a client of yours is going to use depends on the priority and weight values that you've set.