With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cD11HtPhyCurrentExtensionChannel
Cisco DOT11 High-Throughput Physical Current Extension Channel
1.3.6.1.4.1.9.9.607.1.1.2.1.7
This object represents the channel extension offset. The semantics are as follows. noExtension - No extension channel is present and the radio operates in the 20MHz mode. extensionAbove - The extension channel is above the control channel. This is applicable only if the radio operates in the 40MHz mode. extensionBelow - The extension channel is below the control channel. This is applicable only if the radio operates in the 40MHz mode.
Back to CISCO-DOT11-HT-PHY-MIB MIB page.
IPHost Network monitor allows you to monitor cD11HtPhyCurrentExtensionChannel on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.