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• WFQ addresses the situation in
which different users have different requirements.
• Each user flow has its own
buffer and each user flow also has weight.
• Here weight determines its
relative bandwidth share.
• If buffer 1 has weight 1 and
buffer 2 has weight 3, then when both buffers are nonempty, buffer 1 will
receive 1/(1+3)=1/4 of the bandwidth and buffer 2 will
receive ¾ of the bandwidth.
.PNG)
In the above figure,
• In Fluid-flow system, the
transmission of each packet from buffer 2 is completed
at time t=4/3, and the packet
from buffer 1 is completed at t=2 seconds.
• In the above figure buffer1
would receive 1 bit/round and buffer 2 would receive
3 bits/second.
• Packet-by-packet weighted fair
queueing calculates its finishing tag as follows
F(i,k,t) = max{F(i,k-1,t), R(t)}
+ P(i,k,t)/wi
• The above figure also shows the
completion times for Packet-by-packet weighted
fair queueing.
• The finish tag for buffer1 is
F(1,1)=R(0)+1/1 =1 and finish tag for buffer 2 is
F(2,1) =R(0) + 1/3 =1/3.
• Therefore the packet from
buffer 2 is served first and followed by packet from
buffer 1.
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