SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain name for a certain service different from an Internet site. By creating a number of SRV records, you will be able to use the domain with different providers and point it to several servers simultaneously, every single server managing a different service. You could specify the port number for the connection to every single machine, so there will never be any interference. You may as well set different priorities and weight for 2 records which are used for the very same service, but forward to different servers for redundancy or load balancing. Using 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 specific software running on a number of machines with different companies. Which one a customer of yours will use is determined by the priority and weight values that you have set.