Limiting The Rate Of A Port; Traffic Prioritization And Rate Limiting - 3Com SuperStack 3 3812 Implementation Manual

Limiting the Rate of
a Port
Traffic Prioritization
and Rate Limiting
The Switch uses the following queuing mechanisms:
Weighted Round Robin (WRR) — This method services all the traffic
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queues, giving priority to the higher priority queues. Under most
circumstances, this method gives high priority precedence over
low-priority, but in the event that high-priority traffic exceeds the link
capacity, lower priority traffic is not blocked. This is the default
method.
Strict Priority Queuing (SPQ) — This method guarantees that traffic on
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a higher priority queue will always be serviced ahead of traffic waiting
on a lower priority queue. This can have the disadvantage that lower
priority queues may become starved of bandwidth when the higher
priority queues are heavily utilized.
Traffic queues cannot be enabled on a per-port basis on the Switch.
Limiting the rate at which a port can receive or send traffic can be used to
ease congestion on bottlenecks in your network and provide simple
prioritization when the network is busy.
Rate limiting is commonly used in the following situations:
To prevent a high bandwidth client or group of clients from
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dominating the traffic on your network.
To balance the traffic at a bottleneck, such as an external-facing
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router, so that different departments or parts of your network get
similar access across the bottleneck.
The advantage of rate limiting is that it is a simple solution: it is easy to
set up and maintain. It can be used to effectively keep the traffic on your
network to a manageable level.
Traffic prioritization and rate limiting can be used together to effectively
manage the traffic on your network:
Rate limiting will ensure that the traffic on a connection never exceeds
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the rate you specify.
Traffic prioritization will ensure that any packets dropped at times of
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network congestion are of the lowest priority.

Limiting the Rate of a Port

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