3Com MSR 50 Series Configuration Manual page 406

406 C 21: B
HAPTER RIDGING
C
ONFIGURATION
segment, a bridge listens to all Ethernet frames on the segments. When it receives
an Ethernet frame, it extracts the source MAC address of the frame and creates a
mapping entry between this MAC address and the interface on which the
Ethernet frame was received.
As shown in Figure
of which LAN segment 1 is connected with bridge interface 1 while LAN segment
2 is connected with bridge interface 2. When Host A sends an Ethernet frame to
Host B, both bridge interface 1 and Host B receive this frame.
Figure 105 Host A sends an Ethernet frame to Host B on LAN segment 1
MAC address : 00 e0.fcaa .aaaa
Host A
Source address Destination address
00e0 .fcaa .aaaa
Host C
MAC address : 00 e0.fccc .cccc
As the bridge receives the Ethernet frame on bridge interface 1, it determines that
Host A is attached to bridge interface 1 and creates a mapping between the MAC
address of Host A and bridge interface 1 in its bridge table, as shown in
Figure 106.
Figure 106 The bridge determines that Host A is attached to interface 1
MAC address : 00 e0.fcaa . aaaa
Host A
Source address
00e0.fcaa .aaaa
MAC address
00 e0. fcaa. aaaa
Host C
MAC address : 00 e0.fccc . cccc
105, Hosts A, B, C and D are attached to two LAN segments,
00e0. fcbb .bbbb
Bridge interface 1
Bridge
Bridge interface 2
Destination address
00e0.fcbb .bbbb
Bridge table
Interface
1
MAC address : 00 e0.fcbb .bbbb
Host B
LAN segment 1
LAN segment 2
Host D
MAC address : 00 e0.fcdd .dddd
MAC address : 00e0.fcbb .bbbb
Host B
LAN segment 1
Bridge interface 1
Bridge
Bridge interface 2
LAN segment 2
Host D
MAC address : 00e0.fcdd .dddd