Alcatel-Lucent 7450 Quality Of Service Manual page 646

Ethernet service switch; service router; extensible routing system

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overall subscriber density on the ingress forwarding plane. Multipoint shared queuing

eliminates the multipoint queues sparing hardware queues for better subscriber density.

One caveat of enabling multipoint shared queuing is that multipoint packets are no longer

managed per service (although the unicast forwarding queues may provide limit benefit in

this area). Multipoint packets in a multipoint service (VPLS, IES and VPRN) use significant

resources in the system, consuming ingress forwarding plane multicast bandwidth and egress

replication bandwidth. Usually, the per service unicast forwarding queues are not rate limited

to a degree that allows adequate management of multipoint packets traversing them when

multipoint shared queuing is enabled. It is possible to minimize the amount of aggregate

multipoint bandwidth by setting restrictions on the multipoint queue parameters in the QoS

nodes Shared Queue policy. Aggregate multipoint traffic can be managed per forwarding

class for each of the three forwarding types (broadcast, multicast or unknown unicast –

broadcast and unknown unicast are only used by VPLS).

Another caveat for multipoint shared queuing is that multipoint traffic now consumes double

the ingress forwarding plane bandwidth due to dual pass ingress processing.

Figure 39: Multipoint Shared Queuing Using First Pass Unicast Queues

Multipoint shared queuing cannot be enabled on the following services:

demonstrates multipoint shared queuing.

Multipoint Service Queue are ignored (not created) and

Multipoint Packets use First Pass Unicast Service Queues.

Second Pass Multipoint Packets use Shared Multipoint Queues

Unicast Service Queue is

representated by a single

Hardware Queue But Dual Pass

through the Forwarding Plane

Switch Fabric

Quality of Service Guide