Port bandwidth limit

Port bandwidth limit

The main cause of slow network transmission rate is the abuse of the network by some users. When MRTG and other traffic monitoring software detect that the traffic comes from a port, the core switch, aggregation switch, or even access switch can perform necessary processing on the corresponding port, limits the transmission bandwidth, thus limiting the maximum traffic allowed by each user, so that other network users can restore normal network application services.

Step 1: Enter full configuration mode.

Switch # config Terminal

Step 2: Specifies the interface to be configured.

Switch (config) # interface-ID

Step 3: Configure port bandwidth control. Input/Output indicates that the bandwidth limit is applied in the input and output directions. In general, two-way restrictions should be imposed. Access-group ACL-index is used to define the access list that uses the bandwidth limit. BPS is used to define the limited bandwidth, in the unit of BPS, and uses an increment of 8 kbps. Burst-normal is used to define the allowed normal burst rate, and burst-Max is used to define the maximum burst rate. Conform-action conform-action is used to specify the operation performed when the maximum bandwidth is specified, usually transmit, that is, sending is allowed. Exceed-Action exceed-action is used to specify the operation performed when the maximum bandwidth is specified, usually drop, that is, discard.

Switch (config-If) # rate-limit {input | output} [access-group ACL-Index] BPS burst-normal burst-Max conform-action conform-Action exceed-action

Step 4: Returns the privileged configuration mode.

Switch (config-If) # End

Step 5: Displays and verifies the current configuration of this interface.

Switch # Show interface-ID

Step 6: Save the bandwidth limit configuration.

Switch # copy running-config startup-config

For example, if you want to limit the bandwidth of gigabitethernet4/4 to 128 Kbps, when the common burst rate and maximum burst of connection are 8 Kbytes (that is, 64 Kbps) 9 Kbytes (that is, 72 Kbps) in the range, the operation is transmit (transmission means sending); when the range is exceeded, the corresponding operation is drop. Among them, 128 is used to limit the maximum bandwidth, and are used to limit burst connections, so as to ensure that the performance of the entire link is not greatly reduced due to the large amount of transmission by individual users. After limiting the input and output rates, the port configuration is as follows:

Interface gigabitethernet4/4
No switchport
Description tushuguan
IP address 211.82.220.9 255.255.255.248
IP Access-group 120 in
IP address access-group 120 out
Rate-limit output access-group 102 128000 8000 9000 conform-Action transmit exceed-Action drop
Rate-limit input access-group 102 128000 8000 9000 conform-Action transmit exceed-Action drop!

 

In the IP address access list, you only need to set the IP address range (192.168.0.0 ~ 192.168.255.255). The content is as follows:

Access-list 102 permit IP 192.168.0.0 0.255.255 any

Note]Before enabling the bandwidth limit, you must first run the "ip CEF" command in global mode to enable the fast forward technology of the switch.