Switch Operation Overview; Address Table Operation - HP ProCurve Switch 1600M Installation Manual

Introducing the HP Switch 1600M

Switch Operation Overview

Switch Operation Overview

Address Table Operation

Address Learning. As devices are connected to the switch ports, either
directly or through hubs or other switches that are connected to the switch,
the MAC addresses of those devices are learned automatically and stored in
the Switch 1600M's 8000-entry address table. The switch also identifies the
number of the port on which each address is learned so it knows the network
location of each device.
Forwarding, Filtering, Flooding. When the switch receives a packet, it
determines the destination address, looks for the address in the address table.
Based on the port location of that address, the switch then determines whether
to forward, filter-out, or flood the packet.
Network Moves and Changes. When devices are moved in the network,
and become connected to a different switch port, the Switch 1600M automat-
ically recognizes the change and updates the address table with the new port
location of the device. Communication with the device is automatically main-
tained, without any address table manipulation being required.
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forward - if the destination address is on a different port than the one on
which the packet was received, the packet is forwarded to the destination
port and on to the destination device.
filter out - if the destination address is on the same port as the one on
which the packet was received, the packet is filtered out. The switch
thereby isolates local traffic so the rest of the network connected to the
switch does not lose bandwidth dealing with unnecessary traffic.
flood - whenever a new destination address is found in a packet, the
destination address will not yet be in the switch's address table and the
Switch1600M cannot know whether to forward or filter out the packet. In
this case, it sends the packet to all the ports. This is referred to as
"flooding". When the destination device receives the packet, it replies, and
the switch learns the new address from the reply packet. Then, all future
packets destined for that address are forwarded or filtered out appropri-
ately.