SRV, which is an abbreviation for Service, is a DNS record, which allows you to use a domain for a particular service different from a website. By creating a few SRV records, you will be able to use the domain address with different providers and direct it to a number of servers at the same time, each server handling a separate service. You can specify the port number for the connection to each and every machine, so there won't be any interference. You could also set different priorities and weight for 2 records that are used for the exact same service, but point 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 several machines with different companies. Which one a client of yours will use is determined by the priority and weight values that you have set.