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 a website. By creating a couple of SRV records, you’ll be able to use the domain with different providers and direct it to numerous servers at the same time, each server handling a different service. You can specify the port number for the connection to each and every machine, so there won't be any interference. You could also set individual priorities and weight for 2 records which are employed for the exact same service, but forward to different servers for redundancy or load balancing. With an SRV record you can employ your domain or a subdomain under it for a Voice-Over-IP server, for example, and have the actual software running on several machines with different companies. Which one a customer of yours will use will depend on the priority and weight values that you've set.