Port Traffic Controls
Guaranteed Minimum Bandwidth (GMB)
Guaranteed Minimum Bandwidth (GMB)
Feature Default Menu CLI Web
bandwidth-min output Per-Queue:
2%-3%-30%-10%
10%-10%-15%-20%
n/a page 13-21 n/a
show bandwidth output [ port-list ] n/a n/a page 13-24 n/a
Introduction
Guaranteed Minimum Bandwidth (GMB) provides a method for ensuring that
each of a given port’s outbound traffic priority queues has a specified mini-
mum consideration for sending traffic out on the link to another device. This
can prevent a condition where applications generating lower-priority traffic
in the network are frequently or continually "starved" by high volumes of
higher-priority traffic. You can configure GMB per-port.
Terminology
Oversubscribed Queue: The condition where there is insufficient bandwidth
allocated to a particular outbound priority queue for a given port. If additional,
unused bandwidth is not available, the port delays or drops the excess traffic.
GMB Operation
The switch services per-port outbound traffic in a descending order of priority;
that is, from the highest priority to the lowest priority. By default, each port
offers eight prioritized, outbound traffic queues. Tagged VLAN traffic is prior-
itized according to the 802.1p priority the traffic carries. Untagged VLAN
traffic is assigned a priority of “0” (normal).
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