Browser service runs on MailSlot / Server Message Block and thus can be used with all supported transport protocol such as NBF ("NetBEUI"), NBX (IPX/SPX) and NBT (TCP/IP).
Browser service relies heavily on broadcast, so it is not available across network segments separated by routers.
In Windows XP, Computer Browser Service provides backwards compatibility for versions that don't use Active Directory.
For My Network Places, Windows Explorer, and the net view command, Computer Browser is still needed in XP.
For example, when you open Network Neighborhood, your computer contacts the backup browser and requests the list of all available servers.