ZyXEL Communications USG FLEX H Series User Manual page 122

Bridge Overview
A bridge creates a connection between two or more network segments at the layer-2 (MAC address)
level. In the following example, bridge X connects four network segments.
When the bridge receives a packet, the bridge records the source MAC address and the port on which
it was received in a table. It also looks up the destination MAC address in the table. If the bridge knows
on which port the destination MAC address is located, it sends the packet to that port. If the destination
MAC address is not in the table, the bridge broadcasts the packet on every port (except the one on
which it was received).
In the example above, computer A sends a packet to computer B. Bridge X records the source address
0A:0A:0A:0A:0A:0A and port 2 in the table. It also looks up 0B:0B:0B:0B:0B:0B in the table. There is no entry
yet, so the bridge broadcasts the packet on ports 1, 3, and 4.
Table 64 Example: Bridge Table After Computer A Sends a Packet to Computer B
MAC ADDRESS
0A:0A:0A:0A:0A:0A
If computer B responds to computer A, bridge X records the source address 0B:0B:0B:0B:0B:0B and port 4
in the table. It also looks up 0A:0A:0A:0A:0A:0A in the table and sends the packet to port 2 accordingly.
Table 65 Example: Bridge Table After Computer B Responds to Computer A
MAC ADDRESS
0A:0A:0A:0A:0A:0A
0B:0B:0B:0B:0B:0B
Bridge Interface Overview
A bridge interface creates a software bridge between the members of the bridge interface. It also
becomes the Zyxel Device's interface for the resulting network.
Unlike the device-wide bridge mode in ZyNOS-based Zyxel Devices, this Zyxel Device can bridge traffic
between some interfaces while it routes traffic for other interfaces. The bridge interfaces also support
more functions, like interface bandwidth parameters, DHCP settings, and connectivity check. To use the
whole Zyxel Device as a transparent bridge, add all of the Zyxel Device's interfaces to a bridge
interface.
Chapter 7 Interfaces
PORT
2
PORT
2
4
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