SRV, which is an abbreviation for Service, is a DNS record, which enables you to employ a domain for a specific service different from a website. By creating a few SRV records, you will be able to use the domain name with different companies and forward it to numerous servers at once, each and every server handling a separate service. You'll be able to specify the port number for the connection to every single machine, so there will not be any interference. You can also set different priorities and weight for two records which are used for the very same service, but forward to different servers for redundancy or load balancing. By having an SRV record you can use your domain or a subdomain under it for a Voice-Over-IP server, for example, and have the real software running on various machines with different companies. Which one a client of yours is going to use is determined by the priority and weight values that you have set.