I try to monitor traffic for several interfaces on my Cisco 3560 switch via SNMP. The speeds are charted incorrectly; the bandwidths are much higher than shown in PRTG. What can I do?
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This article applies to PRTG Network Monitor 12 or later
Monitoring Cisco Devices Which Use CEF
Cisco uses a technology called Cisco Express Forwarding (CEF). CEF is a Cisco proprietary protocol. This technology increases packet switching speed. For more details, see Cisco Express Forwarding Overview.
If CEF is enabled, PRTG does not see the packets which are transmitted when monitoring via SNMP. It is possible to disable CEF to resolve this issue, but this will affect the performance of the Cisco switch (see Enable and Disable CEF or dCEF).
If you do not want to disable CEF for performance reasons, we recommend using NetFlow (if supported by the specific device) instead to monitor the bandwidth of your Cisco switch (see PRTG Manual: Monitoring Bandwidth via Flows).
Feb, 2013 - Permalink
This article applies to PRTG Network Monitor 12 or later
Monitoring Cisco Devices Which Use CEF
Cisco uses a technology called Cisco Express Forwarding (CEF). CEF is a Cisco proprietary protocol. This technology increases packet switching speed. For more details, see Cisco Express Forwarding Overview.
If CEF is enabled, PRTG does not see the packets which are transmitted when monitoring via SNMP. It is possible to disable CEF to resolve this issue, but this will affect the performance of the Cisco switch (see Enable and Disable CEF or dCEF).
If you do not want to disable CEF for performance reasons, we recommend using NetFlow (if supported by the specific device) instead to monitor the bandwidth of your Cisco switch (see PRTG Manual: Monitoring Bandwidth via Flows).
Feb, 2013 - Permalink