In the Cisco IOS on a Catalyst switch (not on a router), there’s an Interface Mode command called shape round-robin queue bandwidth. More specifically, the command is srr-queue bandwidth.
This command has been around since IOS 12.2(25). For these examples, I’m using a Cisco Catalyst 2960 switch.
Entering the command appended with a question mark will display the command options. Here’s an example:
As you can see, the command options are limit, shape, and share. While we’ll focus on the limit option this time, keep in mind that you can also use the srr-queue bandwidth command to shape and share bandwidth.
For example, let’s say you have a 100-Mb Ethernet port on a Catalyst switch. You’re selling the bandwidth on the port, and a customer has bought 10 Mb of bandwidth. Obviously, you want to limit the outbound bandwidth on the port to 10 Mb instead of the full 100 Mb.
To do so, go to Interface Configuration Mode on the switch port, and apply the srr-queue bandwidth limit command.
Switch(config)# interface FastEthernet 0/1 Switch(config-if)# srr-queue bandwidth limit 90
The 90 sets the outbound bandwidth limit on the port to 90 percent of the port speed. Since this is a 100-Mb port, this should limit the outbound traffic from the port to 10 Mb.