Forwards incoming frame to node if switch knows which of its ports is the one connected to that node.
learns what MAC(s) at other end of link by reading incoming frame's SRC MAC. Stores this port--MAC address pair in its MAC address table.
Floods if node's port not learned yet or is a broadcast frame.
VLAN: virtual LAN defined by set of ports on [one or more trunked] switch[es].
Vlan == broadcast domain == subnet == IP network
Trunk link between switches tags frames with 802.1Q 4B Vlan# header.
end systems are oblivious of Vlan. They only know what IP network (subnet) they are in.
STP: spanning tree protocol avoids loops in network with redundant links.
A LAN with multiple switches (for efficiency and redundancy) can have multiple paths
in the LAN to destination node; a loop might keep a frame cycling forever, so STP eliminates all loops.
Wiring closet rack