Maipu - Rate Limit

In this section, we will see about Maipu Switching QOS feature, Rate Limit.. This is normally used in Service provider scenario, When service provider is using Maipu 3400 Metro E switch. Service provider will limit the bandwidth of particular port, as agreed with customer for example 25 MB. Will configure some burst also.

Let’s see how rate limit feature is used in Maipu switches-

Rate Limitation

In order to avoid overloading and congestion of information which passes in network, Maipu series switches provide rate limitation based on port input direction. It means that it processes limitation to the total rate of port receiving direction. The flow with exceeding rate will be dropped. Configure the parameter as the bandwidth threshold (Kbit, 64K is the minimal granularity) and the burst flow (byte).

To provide different rate limitations for different time periods, each port can be configured with eight rate limitations of different priorities. Each rate limitation can be bound with the time domain. For the valid items, the priority decides which one takes effect. The priority 0 is highest and the priority 7 is lowest.

Basic Commands

### These are port mode commands

Command	Description
rate-limit  pri rate burst-size [time-rang time-rang name]	Configure the rate limitation of a port; the granularity of the rate is 64K and the unit of the burst­­-size is byte.
no rate-limit pri	Cancel one rate limitation of a port

rate-limit  pri rate burst-size

When users configuring the command, the input parameters may be different with the practical value configured successfully. Because the drive adjusts the value input by users according to the chip. The final verity value of the rate is an integer multiple of 64.

When the input value is not 64, the port adjusts the value as a minimal integer multiple of 64 which are greater than the present value. The revised value of Burst-size is an integer multiple of 4096. The average rate of the command at the port inputting direction is the value of the rate. The bursting flow actually is the depth of the token barrel. It means the allowed biggest flow size of each bursting.

Syntax	Description
Rate	Configure the bandwidth threshold with 64k step length and its value range is among 0~16777152.
burst-size	The range of bursting flow is among 4096~16773120.

Configuration template

Configure the rate limitation for a port, the value of the rate is 250000 and the value of the burst-size is 12176.

Switch(config)#port 0/1

Switch(config-port-0/1)#rate-limit 1 250000 12176 time-rang rate

Switch(config-port-0/1)#exit

### Here you can see we are binding, rate limit with Time based ACL. You can configure normally also without time base ACL, like below example - 

port 0/3

port-type uni

uni-isolate isolated

port access vlan  10

rate-limit 46080 4096

ethernet uni-id UNI-port-0/5

ethernet uni-type bundling

load-interval 30

exit

Monitoring:

Display the configuration of port0/1:

Command: show rate-limit port 0/1

Displayed result:

port 0/1

rate-limit 1 250048 12288 time-rang rate

Hope this post will be helpful for you.. 

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