3Com 5500-EI PWR Reference Manual page 810

On Ethernet 1/0/1, assume that the filter command is configured to filter packets destined to IP address
2.2.2.2 and the traffic-limit command is configured to limit the rate of packets sourced from IP address
1.1.1.1 within 128 kbps. Whether packets conforming to the rate limit of 128 kbps, sourced from IP
address 1.1.1.1, and destined to IP address 2.2.2.2 (referred to as packets A later)are dropped
depends on the union-effect of the traffic-limit command.
If the union-effect keyword is not specified, the traffic-limit command issues both the rate limiting
action and the permit action. Whether packets A can pass through depends on the configuration
order of the filter command and the traffic-limit command, with the latest command applying. That
is, if the traffic-limit command is configured after the filter command is configured, packets A can
pass through; otherwise, packets A are dropped.
If the union-effect keyword is specified, the traffic-limit command issues only the rate limiting action.
Whether packets A can pass through depends on the filter command. As for this example, packets
A are dropped.
egress-port interface-type interface-number: Enables traffic policing for the outbound packets of the
port identified by interface-type interface-number. If you specify this keyword, this command applies to
the outbound unicast packets that pass the port and match the ACL rules.
When you configure the traffic policing over a port, an ACL rule can only be applied to one egress
port. If you configure the same ACL rule for different egress ports, only the last configuration takes
effect. To apply the same ACL rule to multiple egress ports, you need to specify different ACL
numbers or rule numbers for the ACL rule.
If the XRN function is enabled, the egress port can only be a port of the local unit. For information
about XRN, refer to XRN Fabric module of this manual.
Do not specify the egress-port keyword when configuring traffic policing on ports in an
aggregation group spanning multiple units. Refer to Link Aggregation Operation for detailed
information about link aggregation.
target-rate: Target packet rate (in kbps) to be set, in the range 64 to 1,000,000. The granularity of rate
limit is 64 kbps. If the number you input is in the ranges N*64 to (N+1)*64 (N is a natural number), it will
be rounded off to (N+1)*64.
burst-bucket-size: Maximum burst traffic size (in KB) allowed, in the range 4 to 512. This argument
defaults to 512 and must be an integer power of 2.
exceed action: Specifies the action to be taken when the traffic rate exceeds the threshold. The action
can be:
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