So in a weighted fake queuing scheduling algorithm, packets are classified based on flows rather than
classes.
So a flow classification would be done as an example on source and destination IP.
Address the protocol and a port number.
The idea with waited for queuing is that a weight is added to a flow based on different criteria such
as IP precedence or RSVP, which is resource reservation protocol.
Weighted for queuing, however, prioritises smaller packets over a larger packets.
So it's a fairer queuing algorithm in that it provides a better quality of service for small packets.
Small packets are generally used for interactive sessions, says an example.
A voice packet may only be 20 bytes in size, whereas an FTP packet could be 1500 points in size.
So larger payloads or larger packets are generally sent by data applications.
Interactive applications such as TELNET or its s, h or voice tend to have smaller packets, so weighted
for queuing priority rises, smaller packets over larger packets, and you can increase that prioritisation
by adding a weight to smaller packets based on IP precedence as an example.
So in brief, a voice packet that's 20 bytes, if it has an IP precedence of five, will appear to be
four bytes in size.
In other words, 20 bytes divided by five.
It appears to be smaller and therefore is prioritized over large data packets.
So it uses a clever scheduling algorithm to prioritize smaller interactive packets, which you can make
appear even smaller by increasing the IP precedence of the packet so that smaller packets are transmitted
before larger packets.
The problem with weighted for queuing is that it doesn't provide bandwidth guarantees.
So as an example, FTP could starve HTTP traffic data flows can starve out one another.
So therefore Cisco developed class based weighted fare queuing where you can guarantee bandwidth to
specific classes and provide dynamic fairness of other flows.
So class based weighted for queuing essentially allows you to create different classes where you can
specify a minimum bandwidth for specific classes of traffic and waited for queuing could be used on
the best effort class to ensure that traffic is handled fairly in the best effort to class.