The fair-queue
command enables fair queuing on an interface.
Router(config-if)#fair-queue
{congestive-discard-threshold}
The congestive-discard-threshold is the number
of messages to queue for high-volume traffic. In other words, the
maximum packets in a conversation held in a queue before they are
discarded. Valid values are 1 to 512, inclusive. The default is 64
messages. The fair-queue 128 command sets the congestive discard
threshold number to 128.
The congestive-discard-threshold policy applies
only to high-volume conversations that have more than one message in
the queue. The discard policy tries to control conversations that
could monopolize the link. If an individual conversation queue
contains more messages than the congestive-discard threshold, that
conversation will not have any new messages queued until the content
of that queue drops below one-fourth of the congestive-discard value.
In the example of fair-queue 128, the queue must contain fewer than 32
entries (1/4 of 128).
In the Figure, interface serial 1 is attached to
a Frame Relay network and is configured to operate at a 56-Kbps link
speed.
WFQ is used by default on serial interfaces at
E1 speeds (2.048 Mbps) and below. WFQ is disabled on serial interfaces
that use X.25 or compressed PPP. LAN interfaces and serial lines,
operating at E3 or T3 speeds, are not available for WFQ.
The fair-queue
command enables fair queuing on an interface. In the Figure, interface
serial 1 is attached to a Frame Relay network and is configured to
operate at a 56-Kbps link speed. The fair-queue
128 command sets the congestive discard
threshold number to 128.
Because conversations may not have any new
messages queued until the content of that queue drops below one-fourth
of the congestive-discard value, a queue must contain fewer than 32
entries (1/4 of 128).
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Lab
Activity |
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Our
company has given us the task of connecting our
east coast office with the west coast office via
ISDN. There will be some large file transfers
over this link but we do not want them to
dominate the link. Since we want low bandwidth
applications such as telnet to be able to get
through at any time, we have decide to use
weighted fair queuing to solve this problem. It
is our responsibility to connect these two
routers together and configure weighted fair
queuing correctly. |
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