With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
dsx3FracIfIndex
dsx3 Frac If Index
1.3.6.1.2.1.10.30.13.1.3
An index value that uniquely identifies an interface. The interface identified by a particular value of this index is the same interface as identified by the same value an ifIndex object instance. If no interface is currently using a channel, the value should be zero. If a single interface occupies more than one time slot, that ifIndex value will be found in multiple time slots.
Back to DS3-MIB MIB page.
IPHost Network monitor allows you to monitor dsx3FracIfIndex on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.