3Com 3C13636 Configuration Manual page 354

3Com Router 3000 Ethernet Family
Configuration Guide
Please be aware that the bridge will forward the broadcast or multicast frames
received on one port to the other ports.
Given that Workstation A sends an Ethernet frame to Workstation B, the bridge
will filter this frame rather than forwarding it, for Workstation B and Workstation A
are located on the same physical network segment.
00e0.fcaa.aaaa
Figure 3-6 Filter(not forward)
Suppose that Workstation A sends an Ethernet frame to Workstation C, and the
bridge does not find the correlation between the MAC address of Workstation C
and the port in the bridging address table, what will the bridge do? The bridge will
forward this frame destined to an unknown MAC address to all ports except the
one on which it is received. In this case, the bridge actually plays the role of a hub
to make sure the continuous information transmission, as shown in the following
figure:
Workstation A
Source address Destination address
00e0.fcaa.aaaa 00e0.fcbb.bbbb
Bridging table
MAC address
Port
00e0.fcaa.aaaa 1
00e0.fcbb. bbbb 1
00e0.fccc . cccc 2
00e0.fcdd.dddd 2
No forwarding
Workstation C
3Com Corporation
Chapter 3 Bridge Configuration
Bridge port 1
Bridge
Bridge port 2
3-5
00e0.fcbb.bbbb
Workstation B
Ethernet segment 1
00e0.fcdd.dddd
Workstation D
Ethernet segment 2