SRV, which is an abbreviation for Service, is a DNS record, which enables you to use a domain name for a particular service different from an Internet site. By setting up a number of SRV records, you can use the domain address with different providers and forward it to a number of servers simultaneously, every single server managing a separate service. You'll be able to specify the port number for the connection to every machine, so there will not be any interference. You could also set different priorities and weight for two records which are used 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 actual software running on several machines with different providers. Which one a client of yours will use is determined by the priority and weight values that you've set.