If you want to see what services are being hosted by a particular svchost.exe instance, you can use the tasklist command from the command prompt in order to see the list of services.
tasklist /SVC
Tag Archives: services
DNS-Based Service Discovery
This document specifies how DNS resource records are named and structured to facilitate service discovery. Given a type of service that a client is looking for, and a domain in which the client is looking for that service, this allows clients to discover a list of named instances of that desired service, using standard DNS queries. This is referred to as DNS-based Service Discovery, or DNS-SD.
via. http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt