Users Guide

414 Fabric OS Administrator’s Guide
53-1002920-02
Ingress Rate Limiting
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• Ingress Rate Limiting
Ingress Rate Limiting restricts the speed of traffic from a particular device to the switch port.
Ingress Rate Limiting does not require a license. Refer to “Ingress Rate Limiting” on page 414
for more information about this feature.
• Quality of Service (QoS)
QoS allows you to categorize the traffic flow between a host and target as having a high,
medium, or low priority. QoS does not require a license. Refer to “QoS” on page 415 for more
information about this feature.
You can use the Adaptive Networking features together to optimize the performance of your fabric.
For example, you can use the features in the following ways:
• You can use Top Talkers to identify the SID/DID pairs that consume the most bandwidth and
can then configure them with certain QoS attributes so they get proper priority.
• If the bottleneck detection feature detects a latency bottleneck, you can use TI zones or QoS to
isolate latency device traffic from high-priority application traffic.
• If the bottleneck detection feature detects ISL congestion, you can use Ingress Rate Limiting to
slow down low-priority application traffic if it is contributing to the congestion.
Ingress Rate Limiting
Ingress Rate Limiting restricts the speed of traffic from a particular device to the switch port. Use
Ingress Rate Limiting for the following situations:
• To reduce existing congestion in the network or proactively avoid congestion.
• To enable you to offer flexible bandwidth-limit services based on requirements.
• To enable more important devices to use the network bandwidth during specific services, such
as network backup.
To limit the traffic, you set the maximum speed at which the traffic can flow through a particular
F_Port or FL_Port. For example, if you set the rate limit at 4 Gbps, then traffic from a particular
device is limited to a maximum of 4 Gbps.
Ingress Rate Limiting enforcement is needed only if the port can run at a speed higher than the
rate limit. For example, if the rate limit is 4 Gbps and the port is only a 2-Gbps port, then Ingress
Rate Limiting is not enforced.
The Ingress Rate Limiting configuration is persistent across reboots.
You should keep in mind the following considerations about Ingress Rate Limiting:
• Ingress Rate Limiting is applicable only to F_Ports and FL_Ports.
• QoS takes precedence over Ingress Rate Limiting.
• Ingress Rate Limiting is not enforced on trunked ports.
Virtual Fabrics considerations
If Virtual Fabrics is enabled and if a port is configured to have a certain rate limit value, you must
first disable the rate limit on the port before moving it to a different logical switch. Ports cannot be
moved when they have rate limit configured on them.