SRV, which is an abbreviation for Service, is a DNS record, which permits you to use a domain name for a certain service different from a website. By setting up a few SRV records, you will be able to use the domain address with different providers and forward it to a number of servers at a time, every single server managing a separate service. You can specify the port number for the connection to every machine, so there will never be any interference. You can also set individual priorities and weight for 2 records that are used for the very same service, but direct to different servers for redundancy or load balancing. By having an SRV record you can employ your domain name or a subdomain under it for a Voice-Over-IP server, for instance, and have the actual software running on several machines with different companies. Which one a customer of yours will use is determined by the priority and weight values you have set.