Very good presentation by Dr. Radia Perlman. The talk discusses spannig tree protocol and new work being done in IETF known as TRILL (TRansparent Interconnection of Lots of Links), which combines the advantages of bridges (layer 2 forwarding devices) and routers (layer 3 forwarding devices).

TFTP (Trivial File Transfer Protocol), a simple form of the File Transfer Protocol (FTP). TFTP uses the User Datagram Protocol (UDP)and provides no security features. It is often used by servers to boot diskless workstations, X-terminals, and to backup routers configurations files.
Some details of TFTP: