With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cpvlanPrivatePortSecondaryVlan
cpvlan Private Port Secondary Vlan
1.3.6.1.4.1.9.9.173.1.2.1.1.1
The VLAN ID of the secondary VLAN configured on this private port. A private port is a port that allows the ingress traffic of the secondary VLAN as well as egress traffic of its associated primary VLAN, but blocks the egress traffic of the isolated VLAN while allowing the egress traffic of the community or twoWayCommunity VLAN depending on the type of the secondary VLAN. Note that a port can join a secondary VLAN only after this secondary VLAN has been associated with a primary VLAN, i.e., the cpvlanVlanAssociatedPrimaryVlan has a non-zero value. The default value of 0 for this object means this port has not joined any secondary VLAN yet.
Back to CISCO-PRIVATE-VLAN-MIB MIB page.
IPHost Network monitor allows you to monitor cpvlanPrivatePortSecondaryVlan on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco optical switches right now.