Most business-class switches and routers support monitoring via SNMP. The main barrier to implementing SNMP monitoring is that so many parameters can be monitored, and it can be very hard to isolate the most important parameters. This example shows how to monitor the status of a specific port. Note that the term “port” includes link aggregation groups (LAGs) or other logical groups of ports like VLANs.

Use Case

A top-of-rack switch has several important link aggregation groups (LAGs). For example, one LAG has connections to two identical routers in a VRRP cluster. Other LAGs provide redundant network paths to independent NICs on the same server. I want to be alerted if the port status changes on any critical LAG. The ISP delivers Internet to a single port on the switch, which I also want to monitor.