SRV, which is an abbreviation for Service, is a DNS record, which permits you to employ a domain name for a particular service different from a website. By setting up a couple of SRV records, you are able to use the domain with different providers and point it to many servers at the same time, each and every server handling a different service. You are able to specify the port number for the connection to every single machine, so there won't be any interference. You can even set different priorities and weight for two records which are used for the exact same service, but direct 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 instance, and have the real software running on a number of machines with different companies. Which one a customer of yours will use will depend on the priority and weight values that you have set.