Symptom
A router sees repeated QFP alerts, such as:
Jan 1 00:00:00.000 UTC: %IOSXE_QFP-2-LOAD_EXCEED: Slot: 0, QFP:0, Load 97% exceeds the setting threshold.
Jan 1 00:00:30.000 UTC: %IOSXE_QFP-2-LOAD_RECOVER: Slot: 0, QFP:0, Load 42% recovered.
Jan 1 00:01:00.000 UTC: %IOSXE_QFP-2-LOAD_EXCEED: Slot: 0, QFP:0, Load 94% exceeds the setting threshold.
Jan 1 00:01:30.000 UTC: %IOSXE_QFP-2-LOAD_RECOVER: Slot: 0, QFP:0, Load 5% recovered.
Jan 1 00:02:00.000 UTC: %IOSXE_QFP-2-LOAD_EXCEED: Slot: 0, QFP:0, Load 83% exceeds the setting threshold.
Jan 1 00:02:30.000 UTC: %IOSXE_QFP-2-LOAD_RECOVER: Slot: 0, QFP:0, Load 51% recovered.
Jan 1 00:03:00.000 UTC: %IOSXE_QFP-2-LOAD_EXCEED: Slot: 0, QFP:0, Load 87% exceeds the setting threshold.
Jan 1 00:03:30.000 UTC: %IOSXE_QFP-2-LOAD_RECOVER: Slot: 0, QFP:0, Load 52% recovered.
Jan 1 00:04:00.000 UTC: %IOSXE_QFP-2-LOAD_EXCEED: Slot: 0, QFP:0, Load 95% exceeds the setting threshold.
Jan 1 00:04:30.000 UTC: %IOSXE_QFP-2-LOAD_RECOVER: Slot: 0, QFP:0, Load 6% recovered.
These alerts could be seen with significantly lower throughput than expected. For example, an ASR1K with an ESP100 could max out its QFP with less than 1Gbps of traffic.
Enhancement for Elephant Flow
Conditions
1> Router;
2> In 16.3.x, 16.6.x, 16.9.x;
3> There's elephant flow(s). This can be confirmed via packet-trace;
4> Performance monitors configured, especially on both LAN and WAN in both directions.
Workaround
1> Configure the performance monitors on WAN only;
2> Upgrade to 16.12.4 or newer which has the optimization of elephant flow.
