Chapter 4. Bridging

This chapter presents background and configuration information for transparent bridging and related bridge functions.

• 4-1: Transparent Bridging

• 4-2: Concurrent Routing and Bridging (CRB)

• 4-3: Integrated Routing and Bridging (IRB)

The router can bridge protocols using one of three methods. Table 4-1 provides a brief comparison of these methods.

Table 4-1. Bridging Comparisons

Bridging Method	Description
Transparent bridging	Allows interfaces within a specified bridge group to bridge all traffic that the router is not configured to route between interfaces in the group.
Concurrent Routing and Bridging	Allows you to bridge a specific protocol on some interfaces while routing it on others.
Integrated Routing and Bridging	Allows you to route and bridge for a given protocol on interfaces in the same bridge group.