With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
mplsInterfaceFailedLabelLookup
mpls Interface Failed Label Lookup
1.3.6.1.3.96.1.2.1.4
This value indicates the number of labeled packets that have been received on this interface and were discarded because there were no matching entries found for them in mplsInSegmentTable.
Back to MPLS-LSR-MIB MIB page.
IPHost Network monitor allows you to monitor mplsInterfaceFailedLabelLookup on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.