ZyXEL Communications ZyWall USG 2000 User Manual page 210

Chapter 10 Interfaces
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 58 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 59 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 ZyWALL's interface for the resulting network.
Unlike the device-wide bridge mode in ZyNOS-based ZyWALLs, this ZyWALL 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 ZyWALL as
a transparent bridge, add all of the ZyWALL's interfaces to a bridge interface.
A bridge interface may consist of the following members:
• Zero or one VLAN interfaces (and any associated virtual VLAN interfaces)
• Any number of Ethernet interfaces (and any associated virtual Ethernet
interfaces)
When you create a bridge interface, the ZyWALL removes the members' entries
from the routing table and adds the bridge interface's entries to the routing table.
For example, this table shows the routing table before and after you create bridge
interface br0 (250.250.250.0/23) between ge1 and vlan1.
Table 60 Example: Routing Table Before and After Bridge Interface br0 Is Created
IP ADDRESS(ES)
210.210.210.0/24
210.211.1.0/24
221.221.221.0/24
222.222.222.0/24
210
PORT
2
PORT
2
4
DESTINATION
ge1
ge1:1
vlan0
vlan1
IP ADDRESS(ES) DESTINATION
221.221.221.0/24 vlan0
230.230.230.192/26 ge3
241.241.241.241/32 ge4
242.242.242.242/32 ge5
ZyWALL USG 2000 User's Guide