Traffic Shaping
An even more proactive approach to handling traffic is traffic shaping . By using traffic shaping, we can ensure a certain amount of bandwidth for certain traffic. With the shape command, we can assign a CIR value, which is the committed information rate in bits per second.
Some optional keywords for the shape command are average, peak, bc-value, and be-value. Table 11-9 lists keywords for this command.
shape {average | peak } cir-value [bc-value ] [be-value ]
|
Shape keyword |
Description |
|---|---|
|
average |
Specifies the average rate, which ensures an expected bandwidth. |
|
peak |
Specifies the peak rate, which allows the traffic to peak to if there is enough bandwidth available. |
|
cir-value |
The committed information rate in bits per second, which is used to define our average or peak values. |
|
bc-value |
The committed burst size, in bits. |
|
be-value |
The excess burst size, in bits. |
11.6.1. Traffic Shaping Example
In this example , we attempt to ensure that our traffic can have at least 300 Kbps, but we are going to allow it to peak to 512 Kbps if there is enough bandwidth available on the interface.
policy-map policy1 class premium bandwidth 300 shape peak 512000
11.6.2. Frame-Relay Shaping
For frame-relay, we can apply traffic shaping commands directly to the interface with the command traffic-shape. For more information and examples, see Chapter 6.