[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Z] UCT (Coordinated Universal Time) UDP broadcasts forwarding 2nd 3rd UNI ( User -Network Interfaces) 2nd unicast RPF 2nd 3rd 4th 5th UNIX workstations logging messages to unreliable protocols UDP up interfaces updating calendar system 2nd upgrading IOS images user configuration mode 2nd 3rd user-to-network interfaces DCEs DTEs username command 2nd utilities syslog 2nd 3rd 4th |