Configuring QoS Traffic Policing and Shaping
OmniSwitch AOS Release 8 Network Configuration Guide December 2017 page 26-26
To configure the global DEI bit setting operation to mark traffic egressing on QoS destination ports, use
the qos dei command with the egress parameter option. For example:
-> qos dei egress
To configure the switch to map ingress traffic marked with the DEI bit, use the qos dei command with the
ingress parameter option. For example:
-> qos dei ingress
To configure the DEI bit operation for an individual port, use the qos port dei with the ingress or egress
parameter option. For example:
-> qos port 1/10 dei egress
-> qos port 1/11 dei ingress
See the OmniSwitch AOS Release 8 CLI Reference Guide for more information about these commands.
Configuring Policy Bandwidth Policing
The policy action maximum bandwidth and policy action maximum depth commands are used to
configure QoS policy actions. Both actions are typically used in combination; the bucket size (depth)
determines how much over the maximum bandwidth the traffic can burst.
The maximum bandwidth and maximum depth actions are configured as part of a QoS policy in which the
condition specifies the type of traffic to rate limit. Maximum bandwidth policies are applied to source
(ingress) ports and/or flows. See the “Bandwidth Policing Example” on page 26-76.
Port Groups and Maximum Bandwidth
If a port group condition (see “Creating Port Groups” on page 26-58) is used in a maximum bandwidth
policy, the bandwidth value specified is shared across all ports in the group.This also applies to flows that
involve more than one port. For example, if a policy specifies a maximum bandwidth value of 10M for a
port group containing 4 ports, the total bandwidth limit enforced is 10M for all 4 ports.
Note the following when configuring ingress maximum bandwidth policies:
• If a policy condition applies to ports that are located on different slots, the maximum bandwidth limit
specified is multiplied by the number of slots involved. For example, if a rule is configured to apply a
maximum bandwidth limit of 10M to ports 1/1, 3/10, and 4/5, then the actual bandwidth limit enforced
for all three ports is 30M.
• On an OmniSwitch 9900, metering is defined per switch ASIC. For example, if a rule is configured to
apply a maximum bandwidth limit of 10M to ports 1/3/7 and 1/3/20 and each port is on a different
ASIC, then the metering is performed for each port resulting in 20M rate-limiting instead of 10M. If
both ports were on the same ASIC, then 10M rate-limiting would apply.
• The maximum traffic received by a destination port is also dependent on how many slots are sending
traffic to the destination port. However, each slot is restricted to sending only 10k.
• If a policy condition applies to ports that are all on the same slot, then the maximum bandwidth value
specified in the rule is not increased.
• Ingress bandwidth limiting is done using a granularity of 64K bps.
• The show active policy rule command displays the number of packets that were dropped because they
exceeded the ingress bandwidth limit applied by a maximum bandwidth policy.
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