The
bandwidth
command allows you to specify the minimum guaranteed bandwidth to be allocated
for a specific class of traffic. MDRR is implemented as the scheduling
algorithm.
The
bandwidth
remaining command specifies a weight for the class to the MDRR.
The MDRR algorithm derives the weight for each class from the bandwidth
remaining value allocated to the class. If you do not configure the
bandwidth
remaining command for any class, the leftover bandwidth is
allocated equally to all classes for which
bandwidth
remaining is not explicitly specified.
Guaranteed Service rate of a
queue is defined as the bandwidth the queue receives when all the queues are
congested. It is defined as:
Guaranteed Service Rate =
minimum bandwidth + excess share of the queue
On ATM interfaces, if there are other bandwidth commands
configured in the same class, the
bandwidth
remaining command cannot be configured.
Restrictions
The amount of bandwidth
configured should be large enough to also accommodate Layer 2 overhead.
A policy map can have all class bandwidths specified in kilobits
per second or percentages but not a mixture of both in the same class.
The
bandwidth
command is supported only on policies configured on outgoing interfaces.
Note |
In the ingress direction,
bandwidth calculations do not include Layer 2 overhead because Layer 2 headers
are stripped off when a packet is received. In other instances, the bandwidth
calculations include the Layer 2 encapsulation. In the case of PoS/SDH, the
encapsulation is 4 bytes; for Ethernet, the encapsulation is 14 bytes; and for
Dot1Q, the encapsulation is 18 bytes.
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