Brocade Network Advisor SAN User Manual v12.1.0 - Manual (Page 1041)

Brocade Network Advisor SAN User Manual 993
53-1002948-01
Bottleneck detection
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FIGURE 420 Bottleneck port indications
Limitations of bottleneck detection
The bottleneck detection feature for latency detection is not recommended for link utilizations
above 85 percent.
The bottleneck detection feature detects latency bottlenecks only at the point of egress, not
ingress. For example, for E_Ports, only the traffic egressing the port is monitored. For FCoE ports,
bottleneck detection monitors traffic going from the FC side to the DCB side, and does not monitor
traffic going in the reverse direction.
Enabling bottleneck alerts and configuring alert parameters
Bottleneck detection is enabled on a switch or fabric basis. It enables both latency and congestion
detection. Consider these points when enabling bottleneck detection:
• If you enable bottleneck detection on a fabric, the feature is applied to all eligible switches in
the fabric and all eligible ports on the switches.
• If you enable bottleneck detection on a switch, the feature is applied to all eligible ports on that
switch.
• You can override switch configuration by changing parameters for specific ports.
• When changing switch-level parameters, such as time and severity threshold values,
bottleneck detection will be disabled, then enabled.
If ineligible ports later become eligible or, in the case of a logical switch, if ports are moved to the
logical switch, bottleneck detection is automatically applied to those ports.
If you add additional switches, including logical switches, to the fabric, bottleneck detection is not
automatically applied, so be sure to enable bottleneck detection on those switches as well.
NOTE
It is recommended that you enable bottleneck detection on every switch in the fabric.
When you enable bottleneck detection, you also determine whether alerts are to be sent when the
bottleneck conditions at a port exceed a specified threshold. The alert parameters include whether
alerts are sent and the threshold, time, and quiet time options. These alert parameters apply to all
ports in the switch, unless you override them later.
After you enable bottleneck detection, you can change the alert parameters on all eligible ports,
switches, and fabrics.