
13-14
Port Traffic Controls
Rate-Limiting
Using Both ICMP Rate-Limiting and All-Traffic Rate-Limiting
on the Same Interface
ICMP and all-traffic rate-limiting can be configured on the same interface.
All-traffic rate-limiting applies to all inbound or outbound traffic (including
ICMP traffic), while ICMP rate-limiting applies only to inbound ICMP traffic.
Note that if the all-traffic load on an interface meets or exceeds the currently
configured all-traffic inbound rate-limit while the ICMP traffic rate-limit on
the same interface has not been reached, then all excess traffic will be
dropped, including any inbound ICMP traffic above the all-traffic limit (regard-
less of whether the ICMP rate-limit has been reached). Suppose, for example:
■
The all-traffic inbound rate-limit on port “X” is configured at 55% of the
port’s bandwidth.
■
The ICMP traffic rate-limit on port “X” is configured at 2% of the port’s
bandwidth.
If at a given moment:
■
Inbound ICMP traffic on port “X” is using 1% of the port’s bandwidth, and
■
Inbound traffic of all types on port “X” demands 61% of the ports’s
bandwidth,
then all inbound traffic above 55% of the port’s bandwidth, including any
additional ICMP traffic, will be dropped as long as all inbound traffic combined
on the port demands 55% or more of the port’s bandwidth.
Displaying the Current ICMP Rate-Limit Configuration
The
show rate-limit icmp
command displays the per-interface ICMP rate-limit
configuration in the running-config file.
Syntax:
show rate-limit icmp [
port-list
]
Without
[
port-list
]
, this command lists the ICMP rate-limit
configuration for all ports on the switch. With
[
port-list
]
, this
command lists the rate-limit configuration for the specified
interface(s). This command operates the same way in any
CLI context.
3500-5400-6200-8200-MCG-Jan08-K_13_01.book Page 14 Monday, January 28, 2008 10:04 AM