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Traffic Shaping

Fortigate 100D Firmware Version  v5.0,build0305 (GA Patch 10)

I currently have a traffic shaping policy using 20Meg "For All Policies Using This Shaper", but some customers are complaining of very slow and occasionally no connection.  I guess from what I have read that this could be due to the "first come first serve basis" of this set up. I was considering using a "For All Policies Using This Shaper" having a 20Meg Maximum & 5Meg guaranteed allocated to 4 policies. My Question is:  With guaranteeing 5Meg to each policy would this still allow one policy to use more than the 5Meg guaranteed when no other policy is sending.  My worry is that with guaranteeing 5Meg x 4 will this guaranteed BW always be reserved and not allow individual policies to use more than the 5Meg during quiet traffic times. My end goal is to allow individual policies to be able to burst at 20Meg but to then not totally prohibit other users who should have a minimum guaranteed BW.

Valued Contributor

See page 10/11 here:


TL;DR: As long as you do not meet your guaranteed bandwidth your traffic gets priority but does NOT block somebody elses traffic if you don't lose it.




Having a full bandwidth for maximum bandwidth is not a recommended settings.

I believe, the session which is already established and which got a bandwidth allocated cannot reversed until that session ends. So, during this time, any other session might experience issues as the full bandwidth is being applied to someone else.


- Fortigate uses a queue system for the traffic shaper. If any policy doesn't have a traffic shaper, that policy falls under a high priority queue. So, make sure you have the traffic shaper applied on all the firewall policies for better results.

- Also, mention the in-bandwidth/out-bandwidth (download/upload) on the WAN interface.


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