Справочник Пользователя для SonicWALL 5.8.1

An ingress module monitors and records the ingress rate for each traffic class. It also monitors 
the egress ACKs and queues them if the ingress rate has to be reduced. According to ingress 
BW availability and average rate, the ACKs will be released.

IBWM maintains eight priority queues, where each priority has one rule that has IBWM enabled. 
The IBWM pool is processed from the highest to lowest priority further shaping the traffic. IBWM 
employs three key algorithms:

This algorithm processes each packet from the WAN and updates the ingress rate of the class 
to which it belongs. It also marks the traffic class if it has over utilized the link. 

Determine that the packet is from the WAN zone and is a firewall packet.

Add the packet length to the sum of packet lengths received so far in the current time 
slice. Deduct the minimum of (GBW, packet length) from link’s credit.

If the sum is greater than the class’s credit, mark the class to be over utilizing the link.

If the packet length is greater than the link’s credit, mark the link as well as the class to 
be over utilized.

This algorithm depicts how the egress ACKs are monitored and processed.

Determine that the packet is to the WAN zone and is a TCP ACK.

If class or interface is marked as over utilizing, queue the packet in the appropriate 
ingress rule queue.

Non-TCP Packets

Feedback

TCP

Packets

Ingress

Packets

Ingress

Packets

Egress

Packets

CBQ per class/priority

Ingress BWM by controlling

ACK Packets

AckQ per class/priority

Calculates and Maintains

Link BW and 

Available BW for class