cmVBridgeNDSL is a read-only integer counting the number of frames the bridge has received from the DSL side of a given interface. An administrator compares this against the Ethernet-side counters (cmVBridgeNUnicast, cmVBridgeNMulticast) to see the balance of traffic flowing from the subscriber side into the bridge. For example, an interface showing steady cmVBridgeNDSL growth but no corresponding growth on the Ethernet-side counters could indicate traffic being dropped somewhere in the bridge rather than forwarded.