X.25 switching
You can use devices supporting X.25 switching as small-sized X.25 PSEs to protect the investment in X.25. Figure 123 describes the relationships among LAPB, X.25, and X.25 switching.
Figure 123: Relation between LAPB, X.25, and X.25 switching
![](images/image119.png)
In addition to X.25, LAPB can carry IP when two devices are directly connected without an X.25 network in between. With an X.25 switching module, a device can work as a small-sized PSE to directly forward packets without using the upper layer service.