With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cIsnsClntInstTcpPort
Cisco iSNS Clnt Inst Tcp Port
1.3.6.1.4.1.9.10.116.1.2.1.1.7
Indicates the TCP port this iSNS client is accepting iSNSP messages on, generally the iSNS well known port. Other TCP ports may be used by the iSNS client as well. The well known TCP port for iSNSP is 3205. If this client cannot currently receive iSNSP messages, then the value is 0.
Back to CISCO-IETF-ISNS-MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor cIsnsClntInstTcpPort 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.