This read-only INTEGER reports the percentage of PPE memory allocated to MAC bridging (1-99 percent, with values from 70 to 99 effectively treated as 70), with the remainder available for NMS communication and routing, supporting roughly 8000 learned addresses versus about 1600 TCP/IP routes or 1200 IPX RIP/SAP pairs at that split. An administrator watches this trade-off when converting a device's role between pure bridging and routing. For example, an admin planning to convert this ES/1 from a bridge to a router notes ppeBridgingMemory is near 99 percent and knows the routing table capacity will need to be increased at the expense of bridging capacity.