Traffic shaping
A FortiProxy provides quality of service (QoS) by applying bandwidth limits and prioritization to network traffic. Traffic shaping is one technique used by the FortiProxy to provide QoS. A basic approach to traffic shaping is to prioritize higher priority traffic over lower priority traffic during periods of traffic congestion. This provides a stabilizing effect for important traffic while throttling less important traffic.
The FortiProxy delivers traffic shaping with queuing. Before a packet egresses an interface, it is first enqueued to a queue using an algorithm such as RED or FIFO. The kernel dequeues the packet based on the HTB algorithm before sending it out. When traffic exceeds the configured bandwidth limits, traffic is delayed for transport until bandwidth frees up. Traffic may be dropped if the queues are full.
Configuration methods
The following table lists the methods to configure traffic shaping on the FortiProxy and their capabilities in order of preference. If both methods are configured, the first will be preferred over the second.
|
Method |
Traffic queuing |
Traffic prioritization |
Guaranteed and maximum bandwidth limits |
|---|---|---|---|
|
Yes |
Traffic is placed into classes. A total of 30 classes are available. For each class, traffic can be configured into five priority levels. |
When applying a traffic shaping profile to an interface’s egress shaping profile, you can configure it to use up to 100% of the interface’s configured bandwidth between all the classes, regardless of the configured priority in each class. The guaranteed bandwidth is always honored. |
|
|
Traffic shaper |
No |
Traffic can be prioritized into the high (2), medium (3), or low (4) levels. When traffic is below the guaranteed bandwidth of the shaper, the traffic is automatically applied the critical level (1). |
No hard limit on the guaranteed bandwidth. Administrators allocate guaranteed bandwidth to all the traffic shapers for an interface and ensure that the sum does not exceed the total outbandwidth of the interface. Traffic under the guaranteed bandwidth of a traffic shaper is given priority 1. If the total traffic with priority 1 exceeds the total outbandwidth, traffic can be dropped. |
The following topics provide information about configuring traffic shaping: