Support For Fixed Rate Limiting And Adaptive Rate Limiting; Configuring Acl-Based Fixed Rate Limiting - Foundry Networks FESX Manual

Foundry Configuration Guide for the FESX, FSX, and FWSX

Support for Fixed Rate Limiting and Adaptive Rate Limiting

X-Series devices support the following types of ACL-based rate limiting:
• Fixed Rate Limiting – Enforces a strict bandwidth limit. The device forwards traffic that is within the limit but
either drops all traffic that exceeds the limit, or forwards all traffic that exceeds the limit at the lowest priority
level, according to the action specified in the traffic policy.
• Adaptive Rate Limiting – Enforces a flexible bandwidth limit that allows for bursts above the limit. You can
configure Adaptive Rate Limiting to forward, modify the IP precedence of and forward, or drop traffic based on
whether the traffic is within the limit or exceeds the limit.

Configuring ACL-Based Fixed Rate Limiting

Use the procedures in this section to configure ACL-based fixed rate limiting. Before configuring this feature, see
what to consider in "Configuration Notes and Feature Limitations" on page 15-2.
Fixed rate limiting enforces a strict bandwidth limit. The port forwards traffic that is within the limit. If the port
receives more than the specified number of fragments in a one-second interval, the device either drops or
forwards subsequent fragments in hardware, depending on the action you specify.
To implement the ACL-based fixed rate limiting feature, first create a traffic policy, then reference the policy in an
extended ACL statement. Lastly, bind the ACL to an interface. Follow the steps below.
1. Create a traffic policy. Enter a command such as the following:
FESX424 Switch(config)# traffic-policy TPD1 rate-limit fixed 100 exceed-action
drop
2. Create an extended ACL entry or modify an existing extended ACL entry that references the traffic policy. For
example:
FESX424 Switch(config)# access-list 101 permit ip host 210.10.12.2 any traffic-
policy TPD1
3. Bind the ACL to an interface.
FESX424 Switch(config)# int e 5
FESX424 Switch(config-if-e5)# ip access-group 101 in
FESX424 Switch(config-if-e5)# exit
The above commands configure a fixed rate limiting policy that allows port e5 to receive a maximum traffic rate of
100 kbps. If the port receives additional bits during a given one-second interval, the port drops the additional
inbound packets that are received within that one-second interval.
Syntax: [no] traffic-policy <TPD name> rate-limit fixed <cir value> exceed-action <action> [count]
Syntax: access-list <num> permit | deny.... traffic policy <TPD name>
Syntax: [no] ip access-group <num> in | out
NOTES:
For brevity, some parameters were omitted from the above access-list syntax. For the complete CLI syntax, see
the Foundry Switch and Router Command Line Interface Reference.
The software allows you to add a reference to a non-existent TPD in an ACL statement and to bind that ACL to an
interface. The software does not issue a warning or error message for non-existent TPDs.
Use the no form of the command to delete a traffic policy definition. Note that you cannot delete a traffic policy
definition if it is currently in use on a port. To delete a traffic policy, first unbind the associated ACL.
<TPD name> is the name of the traffic policy definition. This value can be 8 or fewer alphanumeric characters.
rate-limit fixed specifies that the traffic policy will enforce a strict bandwidth.
15 4 © Foundry Networks, Inc. December 2005