PTP vs NTP: When Microseconds Matter
Most networks need to agree on what time it is to within a second or so, and NTP has done
Monitoring
Knowing something broke before the tickets arrive. Articles tagged Monitoring cover SNMP, syslog, NetFlow, IP SLA and what is worth alerting on.
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SPAN, RSPAN, and ERSPAN: Packet Mirroring on Cisco Switches
Eventually every network problem reaches the point where you have to see the actual packets. Counters lie by omission, logs
IP SLA on Cisco IOS XE: Probes, Thresholds, and Tracked Failover
IP SLA answers "is this path usable," which is not the same question as "is this link up." Captured on CML with IOS XE 17.18.2: ICMP and jitter probes against a deliberately degraded link, then a full tracked failover with the SLA timing out, %TRACK-6-STATE logging the object down, and the...
NetFlow v5 vs v9 vs Flexible NetFlow vs IPFIX
Four names, one job: tell a collector which conversations crossed the router and how big they were. The differences between
Flexible NetFlow on Cisco IOS XE: Records, Monitors, and Exporters
NetFlow answers the question your monitoring dashboard cannot: not "is the link busy" but "who is making