With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
nhrpCacheNbmaSubaddr
nhrp Cache Nbma Subaddr
The value of the NBMA subaddress of the next hop. If there is no subaddress concept for the NBMA address family, this value will be a zero-length OCTET STRING.
Back to NHRP-MIB MIB page.
IPHost Network monitor allows you to monitor nhrpCacheNbmaSubaddr 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.