SRV, which is an abbreviation for Service, is a DNS record, which allows you to employ a domain for a specific service different from an Internet site. By creating a couple of SRV records, you’ll be able to use the domain address with different companies and point it to a number of servers at a time, each server handling a separate service. You are 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 employed for the very same service, but point to different servers for redundancy or load balancing. By having an SRV record you can employ your domain address or a subdomain under it for a Voice-Over-IP server, for example, and have the real software running on several machines with different providers. Which one a client of yours is going to use depends on the priority and weight values that you've set.