Cisco switch port speed limit (1)

Introduction

As the core network switch of our company, the CISCO3550 has been running stably for many years, and its functions can also meet our needs. However, its port speed limit function is not as easy to implement as some other switches, fortunately, the implementation method has been found recently. After the configuration is complete, it is verified with the iperf software. The result shows that this method is effective. The specific implementation steps are as follows.

1. Create an ACL

Because this is a layer-3 Switch, although the speed limit is imposed on the port, we also need to consider the network address passed through this port. In this example, we choose to limit the speed of the 22nd port of the CISCO3550 switch, the port belongs to VLAN66 and the IP address segment is 10.66/16. Therefore, you must create an ACL as follows:

 
 

  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#access-list 15 permit 10.66.0.0 0.0.255.255 
 
 

Ii. Create a class-map

 
 

  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#class-map dkxs  
  
  
 
  
  
3550(config-cmap)#match access-group 15 
 
 

The main purpose of this step is to create a class-map, which references the previously created ACL 15, so that we can operate port 22 in the future.

3. Create policy-map

For testing purposes, we have created multiple policy-maps and set different limited bandwidths, such as 80 k, 1 m, 5 m, and 10 m, as shown below:

 
 

  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#policy-map 80k  
  
  
 
  
  
3550(config-pmap)#class dkxs  
  
  
 
  
  
3550(config-pmap-c)# police 80000 8000 exceed-action drop  
  
  
 
  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#policy-map 1m  
  
  
 
  
  
3550(config-pmap)#class dkxs  
  
  
 
  
  
3550(config-pmap-c)# police 1000000 100000 exceed-action drop  
  
  
 
  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#policy-map 5m  
  
  
 
  
  
3550(config-pmap)#class dkxs  
  
  
 
  
  
3550(config-pmap-c)# police 5000000 500000 exceed-action drop  
  
  
 
  
  
3550#conf t  
  
  
 
  
  
Enter configuration commands, one per line. End with CNTL/Z.  
  
  
 
  
  
3550(config)#policy-map 10m  
  
  
 
  
  
3550(config-pmap)#class dkxs  
  
  
 
  
  
3550(config-pmap-c)# police 10000000 1000000 exceed-action drop 
 
 

Iv. View configuration information

 
 

  
  
3550#show run  
  
  
 
  
  
policy-map 5m  
  
  
 
  
  
class dkxs  
  
  
 
  
  
police 5000000 500000 exceed-action drop  
  
  
 
  
  
policy-map 1m  
  
  
 
  
  
class dkxs  
  
  
 
  
  
police 1000000 100000 exceed-action drop  
  
  
 
  
  
policy-map 80k  
  
  
 
  
  
class dkxs  
  
  
 
  
  
police 80000 8000 exceed-action drop  
  
  
 
  
  
policy-map 10m  
  
  
 
  
  
class dkxs  
  
  
 
  
  
police 10000000 1000000 exceed-action drop