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To monitor Cisco devices, SNMP access is all that is required.
To monitor Cisco devices, SNMP access is all that is required. If Active Discovery and monitoring is not working, the possibilities are:
For other Cisco devices, such as their Aggregation Services Routers (ASR) series, it may be necessary to enable the sending SNMP TRAPs in the device configuration in order to enable SNMPd for queries by our Collector. From the CLI of the Cisco device, enter:
snmp-server enable traps
snmp-server host version 2c
If after examining the configuration on the router you cannot see why SNMP is not working, it may help to run debugging to see if the requests are getting to the device, and if they are being answered. From the CLI of the Cisco device, enter:
debug snmp packet
This will display all SNMP packets that are arriving and being replied to. Also, please ensure that SNMP TRAP traffic on port 162 UDP is unrestricted between your Collector machine and the monitored device.
If abnormally large interface utilization is being observed via SNMP on Cisco switches, you may need to set up your Cisco device to support 64-bit interface counters.
Affected Devices and iOS Versions include:
Cisco devices might provide one or both sets of interface counters based on RFC1213 and RFC2233 standards.
The ifTable in RFC1213 is the traditional interface counters that almost all SNMP devices support. It defines 32-bit counters for inbound and outbound octets (ifInOctets/ifOutOctets) that are used for bandwidth calculation. These 32-bit counters for high speed devices can wrap over too quickly. For example, a 10 Mbps stream of back-to-back, full-size packets causes ifInOctets to wrap in just over 57 minutes. At 100 Mbps, the minimum wrap time is 5.7 minutes, and at 1 Gbps, the minimum wrap time is 34 seconds. If the counter wraps more than once between Relator interval, the calculation is no longer valid.
There are two potential courses of action for resolving this issue:
Note: See also the SNMP Counters: Frequently Asked Questions Cisco support document for more information.
NTP is also checked on many Cisco devices to ensure that time is correctly synchronized. So, if you use NTP access-groups, ensure the LogicMonitor Collector is allowed to query the Cisco device and that port 123 TCP/UDP is unrestricted between the host and your Collector machine.
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