Alcatel-Lucent 1643 AMS Applications And Planning Manual page 231

Ethernet Overview
Classification, queueing and scheduling
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Flow classification
The flow classifier determines into which flow each incoming packet is mapped. On
customer-role ingress ports, a number of flows can be defined, based on port, user
priority, VLAN ID, IP-ToS field and destination MAC address. For each flow a rate
controller can be specified (CIR/PIR value).
Apart from these flows based on input criteria, a default flow is defined for packets
that do not fulfil any of the specified criteria for the flows, e.g. untagged packets that
have no user priority field. Thus, untagged traffic is classified per port. All traffic on a
certain port is treated equally and attached a configurable default port user priority
value to map the traffic on the appropriate queues.
A default user priority can be specified on port level to be added to each packet in the
default flow (see
behaviour for the default flow can be specified. The same fixed mapping table from
user priority to traffic class to egress queue is applied to packets in the default flow as
to packets in the specified flows.
Provided that Quality of Service - Classification, Queueing and Scheduling (QoS CQS,
cf. "Quality of Service configuration options" (p.
assigned a traffic class by using QoS profiles (see
(p. 11-64)).
Each traffic class is associated with a certain egress queue (see
assignment" (p.
Ingress direction for network-role ports
For network-role ports, two cases need to be differentiated:
• On I-NNI ports, explicit provisioning of the flow identification (flow configuration)
is not provisionable. I-NNI ports always have the default QoS profile assigned. On
an I-NNI port, the only purpose of the flow classifier is to evaluate the traffic class.
The traffic class determines the egress queue.
• E-NNI trunk ports may be split in so-called virtual ports which can be provisioned
by means of virtual port descriptors (VPDs). Explicit provisioning of the flow
identification (flow configuration) enables the DiffServEdge function for this
fraction of the network-role port. Ingress rate control of these virtual ports is the
same as for customer-role ports.
Ingress rate control
Ingress rate control is a means to limit the users access to the network, in case the
available bandwidth is too small to handle all offered ingress packets.
A rate controller has two parameters, a provisionable committed information rate CIR
(or PIR, if CIR = 0), see below), and a committed burst size (CBS). The committed
burst size is the committed information rate multiplied by 0.11 seconds.(CBS = 0.11
seconds × CIR).
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365-312-801R7.2
Issue 3, May 2007
"Default user priority" (p.
11-61)).
Alcatel-Lucent - Proprietary
See notice on first page
11-59)). Furthermore, the rate controller
11-52)) is enabled, each flow can be
"Quality of Service provisioning"
"Traffic class to queue
11-55