SRV, which is an abbreviation for Service, is a DNS record, which allows you to use a domain name for a specific service different from an Internet site. By creating a few SRV records, you are able to use the domain with different providers and forward it to several servers simultaneously, every single server managing a different service. You could specify the port number for the connection to every machine, so there will never be any interference. You could also set different priorities and weight for two records that are employed for the exact same service, but forward to different servers for redundancy or load balancing. With an SRV record you can use your domain address or a subdomain under it for a Voice-Over-IP server, for example, and have the real software running on a number of machines with different providers. Which one a customer of yours is going to use is determined by the priority and weight values that you've set.