NETMG10

A MF classifier would use packet matching technique such as ACL. A BA classifier will match the DSCP value in the DS field.

A queue is a data structure that holds packets that are awaiting transmission. A scheduler is a mechanism for selecting the next packet in the queue for transmission.

A video stream that needs half the bandwidth of T1 will be provided that by WFQ if there are two flows. As more flows are added, the video stream gets less of the bandwidth because WFQ's mechanism creates Fairness. If there are 10 flows, the video stream will get only 1/10th of the bandwidth, which is not enough.

CBWFQ provides this. The network administrator defines a class, places the video stream in the class, and tells the router to provide the minimum bandwidth for the class. Video is now given the bandwidth that it needs. A default class is used for the rest of the flow. This class is serviced using flow0based WFQ schemes allocating the remainder of the bandwidth (half the TL, in this example).

Tail drop is a simple form of queue management where new packets that arrive to a full queue are dropped.

Active queue management such as RED (random early detection), drops packet before a queue becomes full. The rationale is that an aggressive flow will represent most of the arriving traffic and therefore it is likely that a RED will drop a packet of an aggressive session.

A policer typically will either drop packet or rewrite its DSCP value to one with a higher drop precedence (For example from AF31 to AF32).

A shaper typically delays excess traffic using a buffer, or queuing mechanism, to hold packets and shape the flow when the data rate of the source is higher than expected.

LLQ with maximum bandwidth of 48kbps

LLQ with maximum bandwidth of 460kbps

CBWFQ with minimum bandwidth of 384 kbps

CBWFQ with minimum bandwidth of 460kbps

FIFO or WFQ