ATL Telecom R1-SW Ethernet Switch - Manual (Page 174)

R1-SW24L2B User’s Manual
9-6
Packet Marker
Packet marker marks 802.1P field or ToS field with QoS level. QoS level of a packet can use the
value decided by the classifier or be changed by QoS profiles. It is called “remarking” that the
first decided level is changed and marked by QoS profiles.
Policer
Policer can limit bandwidth to make users only use engaged traffic. Policer measures traffic
flow rate by traffic flow, which classified by classifier, and limits traffic not to use over engaged
bandwidth.
Policer consists of metering and action block. Metering measures traffic flow rate and compares
the result of traffic flow rate to engaged bandwidth, then informs the comparing result to action
block. Action block decide how to process traffic depending on the result.
There are three methods to process the result as follows:
y Pass: transmits packets without the result.
y Drop: Discard packets which exceed bandwidth.
y Mark: Remark packets which exceed bandwidth.
Policer Variables
To use Policer function, you should understand the following variables.
y CIR (Committed Information Rate)
Engaged Bandwidth. It is also called Average rate or Guaranteed rate.
y PIR (Peak Information Rate)
Maximum bandwidth
y CBS (Committed Burst Size)
Packet size that can be received for one time. It is also called Average burst size.
y PBS (Peak Burst Size)
Maximum packet size that can be received for one time
y EBS (Excessive Burst Size)
Gap between received packet size and CBS