Description | This article explains how to mitigate packet loss when FEC is used. |
Scope | FortiOS. |
Solution |
FEC does not support NPU offloading. However traffic that does not require FEC can be identified and offloaded. This is improving the performance for traffic that can be offloaded. Based on the requirements offloading can be enabled under phase1:
config vpn ipsec phase1-interface
This can cause packet loss caused by anti-replay. Refer to this KB article: Technical Tip: Explaining IPSEC Anti-replay and preventing packet drops
The behavior is expected when npu-offloading and FEC is enabled. To avoid experiencing packet loss ,offloading or anti-replay can be disabled.
To disable offloading:
config vpn ipsec phase1-interface
To disable anti replay:
config vpn ipsec phase2-interface
An additional recommended measure is to make sure there is a dedicated firewall policy for traffic sensitive to packet loss, where FEC is enabled to separate it from other traffic that will not have FEC applied to it:
config firewall policy edit <id> ......... set fec enable next end |
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