With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
bgp4PathAttrIpAddrPrefixLen
bgp4 Path Attribute Ip Address Prefix Length
1.3.6.1.2.1.15.6.1.2
Length in bits of the IP address prefix in the Network Layer Reachability Information field.
Back to BGP4-MIB MIB page.
IPHost Network monitor allows you to monitor bgp4PathAttrIpAddrPrefixLen 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.