- 3Com Switch Owner Manual

Bridging 49
T0008-16F Release 5.2M
Transparent Bridging for Ethernet LANs
Transparent Bridge
Forwarder Example
Figure 27 shows how the Forwarder and the Hardware Accelerator process a frame.
Figure 27. How the Forwarder and Hardware Accelerator Process a
Frame
Forwarder
Statistics
In addition, the Forwarder collects the following types of statistics:
• Filtering
• LAN link
• WAN link
• Link error
A frame arrives at the
TB Forwarder.
Is
the MAC
Source Address in the
forwarding
table?
Is
the MAC
Destination Address in
the forwarding
table?
TB Forwarder checks
if any filters are set.
Do
filters
match?
TB Forwarder gives the
frame to the appropriate
handler as found in the
forwarding table.
Drop
the frame.
Do
filters
match?
TB Forwarder checks
if any filters are set.
Do
filters
match?
Drop
the frame.
Handler sends
the frame.
Is
the inbound
flag for a Unicast or
Multicast frame
set?
Is
the MAC
Source Address on the
Permanent Station
Address
List?
Drop
the frame.
Learn the Source
Address.
YES
NO
TB Forwarder gives the
frame to the handlers
that are in the
forwarding state.
NO
NO
YES
NO
YES
NO
NO
YES
YES
NO
YES
YES
YES