Bridge Groups and Bridge Group Interfaces

You configure transparent bridging by creating one or more bridge groups on the router. A bridge group is a collection of network interfaces (ports) that forms a broadcast domain. Each bridge group has its own set of forwarding tables and filters and, as such, functions as a logical transparent bridging device. For information about the maximum number of bridge groups that you can configure per E-series router, see JUNOSe Release Notes, Appendix A, System Maximums.

After you create a bridge group, you associate one or more network interfaces with the bridge group. This association is called a bridge group interface, or simply bridge interface. For information about the maximum number of bridge interfaces that you can configure per line module and per E-series router, see JUNOSe Release Notes, Appendix A, System Maximums.

Figure 38 shows an example of a simple transparent bridging network configuration that illustrates the concepts discussed so far in this section.

Figure 38: Bridge Group with Fast Ethernet and Gigabit Ethernet Bridge Interfaces

In Figure 38, a bridge group named westford01 is configured on the E-series router, which allows the router to function as a transparent bridge between a Fast Ethernet LAN segment and a Gigabit Ethernet LAN segment. The bridge group includes two bridge interfaces. The bridge interface associated with port 1 is stacked on a VLAN subinterface over a Fast Ethernet interface. The bridge interface associated with port 2 is stacked on a VLAN subinterface over a Gigabit Ethernet interface.

Table 21 presents a simple representation of the forwarding table for bridge group westford01.

Table 21: Sample Bridge Group Forwarding Table

Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice.