QoS: Marking using Policers

Traffic policers measure the traffic rate for data entering or exiting an interface with the goal of determining whether a traffic contract has been exceeded.  The traffic contract consists of two components:

  • Traffic Rate configured in bits/second
  • Burst Size: configured as a number of bytes

If traffic is within the contracted rate its considered to be conformed and may pass through.

If traffic exceeds  the contracted rate its subject to being dropped.

However there is a compromise action that takes place in which a policer marks down packets instead of dropping them.  It remarks the exceeded packet using IPP or DSCP to a value that makes the packet more likely to be discarded downstream but still allows the packet to pass through the local router.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s