Nortel Web OS 10.0, Application Manual

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Web OS 10.0 Application Guide
Chapter 17: Bandwidth Management
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212777-A, February 2002
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When Virtual Matrix Architecture (VMA) is not enabled, bandwidth classification is done
on the ingress side of the switch (at the ingress port or designated port) and can be based
on the following: source port, VLAN, filters, Virtual Internet Protocol (VIP) address, ser-
vice on the Virtual server, URL, and so on.
When VMA is enabled, traffic classification that is not based on filters or Server Load
Balancing (SLB) is done on the ingress port—that is, the port on which the frame is
received (not the client port or the server port). If the traffic classification is filter-based or
SLB traffic, then the classification occurs on the designated port.
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– VMA is recommended when Bandwidth Management is enabled.
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Bandwidth management occurs on the egress port of the switch—that is, the port from
which the frame is leaving. However, in the case of multiple routes or trunk groups, the
egress port can actually be one of several ports (from the point-of-view of where the
queues are located).
Rate management is controlled by using queues for each contract and by scheduling when
frames are sent from each queue. Each frame is put into a managed buffer and placed on a
contract queue. The time that the next frame is supposed to be transmitted for the contract
queue is calculated according to the configured rate of the contract, the current egress rate
of the ports, and the buffer size set for the contract queue. The scheduler then organizes all
the frames to be sent according to their time-based ordering and meters them out to the
port.
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OTE
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Bandwidth management and port mirroring cannot be enabled at the same time.