SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain name for a certain service different from a site. By creating a number of SRV records, you will be able to use the domain address with different providers and forward it to a number of servers at once, each server handling a different service. You are able to specify the port number for the connection to each machine, so there will not be any interference. You may as well set different priorities and weight for 2 records that are employed for the exact same service, but forward 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 specific software running on several machines with different companies. Which one a customer of yours is going to use is determined by the priority and weight values which you have set.