CANOGA PERKINS 9145EMP NID Software Version 4.0 - Manual (Page 216)

Bandwidth Profiling 9145EMP NID Software User’s Manual
Shapers
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A policer classifies ingress frames as green, yellow or dropped (that is, frames it decides to drops
because they exceed the contract). Yellow frames are indicated by the DE bit set in the outer tag
on the egress (NET) port. If the frames are double tagged according to the service multiplexing
configuration, then the DE bit is replicated in the outer (S) and tunnel (T) tag.
The CFI bit in the ingress C-Tagged frames remain unchanged and is not copied to the egress
outer tag.
A Service Multiplexing record associated with a policer, either at SM level or at the CoS flow
level, cannot be deleted as long as the policer is still configured.
For steps for configuring port-level policing, see the section “Port-level Policing” on page 60.
13.3 Shapers
There are 16 shapers in the system. They cannot be deleted or created but you can disable or
enable them. An unassigned shaper, that is, a shaper without a profile, is always disabled. In
principle, one shaper is assigned for each Network Port queue; however, several queues can be
assigned to the same shaper.
The 16 shaper entities are created automatically at system startup. By default:
• Shaper 1 is enabled, and assigned to a best effort egress bandwidth profile. Internally, all
queues are assigned to this shaper by default.
• Shaping is disabled for the remaining 15 shapers and the shapers are not assigned.
In order to enable the shaping function, you must associate a shaping bandwidth profile with a
shaper, assign a shaper with a particular entity, and enable the shaping administratively.
Changing the profile associated with a shaper is possible only if the shaping function is disabled.
A shaper can be assigned to:
• The entire network port. In this case, the entire egress traffic is shaped in a single bucket,
according to a single traffic profile. By default, at system startup, the network port is
assigned to shaper 1, which in turn has a best effort bandwidth profile associated.
• A single network port egress queue, or a group of network port egress queues. This
allows you to specify the finest granularity for the traffic shaping. Several queues can be
assigned to the same shaper. It is the responsibility of the user to insure consistency
between the desired shaping outcome and the queue classification configuration.
13.3.1 Shaper statistics
The shaper is a component of the queue scheduling algorithm. Frames are not dropped because
of the shaper, but because the underlying queue is full. The queue may be full because the traffic
came too fast (from the user side) compared to the shaping profile.
Shaper related statistics are therefore the same as egress queue statistics. The following
statistics are collected per queue:
• Total classified packets (that is, packets assigned to the queue)
• Total packets dropped according to drop profile (not applicable if shaping is enabled on
the queue)
• Total queued green packets and total queued yellow packets