Finally, we come to browsing. This was left to last, not because it is hardest, but because it's both optional and partially dependent on a protocol that doesn't guarantee delivery of a packet. Browsing is hard to diagnose if you don't already know all the other services are running.
Browsing is purely optional: it's just a way to find the servers on your net and the shares that they provide. Unix has nothing of the sort and happily does without. Browsing also assumes all your machines are on a local area network (LAN) where broadcasts are allowable.
First, the browsing mechanism identifies a machine using the unreliable UDP protocol; then it makes a normal (reliable) TCP/IP connection to list the shares the machine provides.