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 setting up a couple of SRV records, you are able to use the domain name with different companies and point it to numerous servers at a time, each server handling a separate service. You are able to specify the port number for the connection to every single machine, so there won't be any interference. You can also set different priorities and weight for 2 records that are used for the exact same service, but point to different servers for redundancy or load balancing. By having an SRV record you can employ your domain 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 providers. Which one a customer of yours is going to use will depend on the priority and weight values that you've set.