Switch Operation And Features; How Does The Switch Compare To A Bridge; Forwarding Of Packets - 3Com 1000 User Manual

Switch Operation and Features

How Does the Switch Compare to a Bridge?

The table below shows how Switch 1000 operation
compares to that of a conventional IEEE 802.1d
bridge.
IEEE 802.1d Bridge
All ports
Address Learning
Forwarding Mode Store and forward
Operation when Discard packets
packet buffers full
Spanning Tree Supported
Action on Flood all ports
Unknown
Destination
Address
Database size 4000 addresses
In all other ways, Switch 1000 and bridge opera-
tion is identical.
Switch 1000
All ports except back-
bone port
Fast Forward, Frag-
ment Free, Store and
forward, or Intelligent
Invoke Intelligent
Flow Management to
suppress transmis-
sions at source
Optional
Forward to backbone
port, or forward to
all ports
500 addresses

Forwarding of Packets

The table below shows how a packet is processed
when it arrives at the Switch 1000.
Packet Source Destination
Address
Any port EXCEPT back- Unknown
bone (Unicast packet)
Same port as
source address
Another port (not
backbone)
Any port EXCEPT back- Not applicable
bone (Multi/Broadcast
packet)
Backbone port Unknown
(Unicast packet)
Known port (not
backbone)
Backbone port Not applicable
(Multi/Broadcast packet)
You can configure the Switch to forward packets
with an unknown destination address to all ports in
the same VLAN as the source port. Refer to
Up the Switch Unit"
tion.
About the Switch 1000
Action
Forward to back-
bone port only, or
forward to all ports
Filter
Forward to specific
port only
Forward to all ports
(including back-
bone) in the same
VLAN as source port
Filter
Forward to known
port only
Forward to all ports
within specific VLAN
"Setting
on page 4-9 for more informa-
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