Alcatel-Lucent 7750 Configuration Manual page 392

Interfaces
SAP and subscriber host queues can be port-parented to a Vport scheduler in a similar way they port-parent
to a port scheduler or can be port-parented directly to the egress port-scheduler if the agg-rate is used.
Parameters
name — Specifies the name of the Vport scheduling node and can be up to 32 ASCII characters in length.
This does not need to be unique within the system but is unique within the port or a LAG.
agg-rate
Syntax [no] agg-rate rate
Context config>port>sonet-sdh>path>access>egress>vport
configure>port>ethernet>access>egress>vport
Description This command configures an aggregate rate for the Vport. The agg-rate rate, port-scheduler-policy and
scheduler-policy commands are mutually exclusive. Changing between the use of a scheduler policy and the
use of an agg-rate/port-scheduler-policy involves removing the existing command and applying the new
command.
Parameters agg-rate — Specifies the rate limit for the Vport.
Values
egress-rate-modify
Syntax [no] egress-rate-modify
Context configure>port>ethernet>access>egress>vport
configure>port>sonet-sdh>path>access>egress>vport
Description This command is used to apply HQoS Adjustment to a Vport. HQoS Adjustment refers to the dynamic
adjustment of the rate limit at an QoS enforcement point within 7x50 when the multicast traffic stream is
disjointed from the unicast traffic stream. This QoS enforcement point within 7x50 represents the physical
point further down in the access part of the network where the two streams join each other and potentially
can cause congestion.
An example would be a PON port which is shared amongst subscriber's multicast traffic (single copy of
each channel) and subscriber's unicast traffic. The bandwidth control point for this PON port resides in the
upstream 7x50 BNG node in the form of a Vport. In case that the multicast delivery method in the 7x50
BNG utilizes redirection, the multicast traffic in the 7x50 BNG will flow outside of the subscriber or the
Vport context and thus will bypass any bandwidth enforcement in 7x50. To correct this, a Vport bandwidth
adjustment is necessary in 7x50 that will account for the multicast bandwidth consumption that is bypassing
Vport in 7x50 but is present in the PON port whose bandwidth is controlled by Vport.
An estimate of the multicast bandwidth consumption on the PON port can be made at the Vport level based
on the IGMP messages sourced from the subscribers behind the PON port. This process is called HQoS
Adjustment.
A multicast channel bandwidth is subtracted from or added to the Vport rate limit according to the received
IGMP Join/Leave messages and the channel bandwidth definition policy associated with the Vport (indi-
rectly through a group-interface). Since the multicast traffic on the PON port is shared amongst subscribers
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7750 SR Interface Configuration Guide