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Cabletron Systems SmartSwitch User Manual

Page 265

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SmartSwitch Router User Reference Manual

265

Chapter 17: Access Control List Configuration Guide

15.1.1.0/24). Then you use an ip-policy command to specify what happens to packets that
match the selection criteria (in this example, forward them to address 10.10.10.10). The
following commands illustrate this example.

This command creates a Profile ACL called prof1 that uses as its selection criteria all telnet
packets travelling from source network 9.1.1.0/24 to destination network 15.1.1.0/24:

This Profile ACL is then used in conjunction with the ip-policy command to cause packets
matching prof1’s selection criteria (that is, telnet packets travelling from 9.1.1.0/24 to
15.1.1.0/24) to be forwarded to 10.10.10.10:

See

“IP Policy-Based Forwarding Configuration Guide” on page 209

for more information

on using the ip-policy command.

Using Profile ACLs with the Traffic Rate Limiting Facility

Traffic rate limiting is a mechanism that allows you to control bandwidth usage of
incoming traffic on a per-flow basis. A flow meeting certain criteria can have its packets
re-prioritized or dropped if its bandwidth usage exceeds a specified limit.

For example, you can cause packets in flows from source address 1.2.2.2 to be dropped if
their bandwidth usage exceeds 10 Mbps. You use a Profile ACL to define the selection
criteria (in this case, flows from source address 1.2.2.2). Then you use a rate-limit
command to specify what happens to packets that match the selection criteria (in this
example, drop them if their bandwidth usage exceeds 10 Mbps). The following commands
illustrate this example.

This command creates a Profile ACL called prof2 that uses as its selection criteria all
packets originating from source address 1.2.2.2:

The following command creates a rate limit definition that causes flows matching Profile
ACL prof2’s selection criteria (that is, traffic from 1.2.2.2) to be restricted to 10 Mbps for
each flow. If this rate limit is exceeded, the packets are dropped.

When the rate limit definition is applied to an interface (with the rate-limit apply
interface

command), packets in flows originating from source address 1.2.2.2 are dropped

if their bandwidth usage exceeds 10 Mbps.

ssr(config)# acl prof1 permit ip 9.1.1.0/24 15.1.1.0/24 any any telnet 0

ssr(config)# ip-policy p5 permit profile prof1 next-hop-list 10.10.10.10

ssr(config)# acl prof2 permit ip 1.2.2.2

ssr(config)# rate-limit client1 input acl prof2 rate-limit 10000000
exceed-action drop-packets