Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring HQoS (Rev.03)
QoS/HQoS Implementation
© 2008 Foundry Networks, Inc.
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does not replicate the multicast packets destined towards the User side, in order to save its own
resources and the bandwidth on the internal connection to the Packet Processor.
The internal connection between the Packet Processor and the ES Processor is implemented using
dual 1Gb/s links. The traffic in both directions is divided over these links using an intelligent,
service-based load-balancing mechanism, which is managed automatically. It is possible to
manually configure the Packet Processor QoS mechanisms over the internal connection ports in
order to take advantage of the intelligent oversubscription control functionality.
Traffic Flows
Interfaces can be divided into two main types: User (access side) and Network (uplink side). The
traffic can flow through the device between each interface type and the same type, or the other
type, creating overall four possible flows:
1.
User-to-User (also called Local Switching Path)
2.
User-to-Network (also called Add Path, as it adds traffic to the service provider’s network)
3.
Network-to-User (also called Drop Path, as it drops traffic from the service provider’s
network)
4.
Network-to-Network (also called Pass-Through Path)
Figure 9: Traffic Flow through the Device
For each flow, a different set of QoS/HQoS mechanisms can be applied on the flowing traffic. The
following subsections describe in detail the exact QoS/HQoS mechanisms that can be applied on
the traffic flowing through each one of the four possible paths.
Local Switching Path: User to User
Figure 10
shows the QoS actions applied to the locally switched traffic on its way through the
device. Please note that in this case the traffic doesn’t go through the ES Processor.