SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain for a specific service different from a website. By setting up a number of SRV records, you can use the domain name with different providers and point it to many servers simultaneously, each server managing a different service. You'll be able to specify the port number for the connection to every machine, so there won't be any interference. You may as well set different priorities and weight for two records that are employed for the very same service, but forward to different servers for redundancy or load balancing. Using an SRV record you can employ your domain address or a subdomain under it for a Voice-Over-IP server, for instance, and have the real software running on a number of machines with different companies. Which one a customer of yours is going to use is determined by the priority and weight values which you have set.