In case oversubscription support is disabled (QoS_osub = disabled), then the
provisioning of the PIR is ignored and system-internally the value of the CIR is
taken instead. This leads to a strict policing of all flows entering at a customer-role
port of this VS.
Rate control modes
The rate controller can operate in two different modes:
1. Strict policing mode (CIR = PIR)
The strict policing mode allows each user to subscribe to a minimum committed SDH
WAN bandwidth, or CIR (committed information rate). This mode will guarantee the
bandwidth up to CIR but will drop any additional incoming frames at the ingress LAN
port that would exceed the CIR.
All packets below CIR are marked green; all packets above PIR (= CIR) are marked
red and dropped.
2. Oversubscription mode (CIR < PIR)
The oversubscription mode allows users to burst their data flow to a maximum
available WAN bandwidth at a given instance. When PIR is set equal to the maximum
of the physical network port bandwidth, then a user is allowed to send more data than
the specified CIR. The additional data flow above CIR has a higher dropping
probability.
The following two cases can be differentiated in oversubscription mode.
Information
rate
0 kbit/s CIR=PIR
green red
CIR = PIR MAX<
Information
rate
0 kbit/s CIR
green yellow
0 < CIR < PIR = MAX
Traffic provisioning
Classification, queueing, and scheduling
....................................................................................................................................................................................................................................
365-312-807R7.2
Issue 4, May 2007
Alcatel-Lucent - Proprietary
See notice on first page
8-87
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