We've been having this problem where spoke to spoke traffic on our 1G internet linked sites are seeing traffic in one direction performing at about 400Mbit's (iPerf3 testing) The other direction is about 40-50Mbit's. This is using TCP traffic. No bandwidth policies in use.
The problem does affect all other sites on SD-WAN but we've been testing higher capacity sites.
When using UDP we are seeing 900Mbit's in one direction and about 400Mbit's in the other which is much better. I'd expect UDP to perform better but not this much?
We've got 700+ sites to the one HA pair hub.
We' are upgrding to 16.16 in a few days on the hubs. The spokes are already at this version. Just something else to try.
We are seeing in the dashboard, occasional reports of packet loss across one of our data centre switches the hub is behind. All are tests are performed during quiet and busy network periods but the results are about the same.
There are two Fortigate firewalls in the path at the hub end but we have been assured no issues in this space. Link capacity across the DC is fine and all devices and interfaces not reporting over use.
We've got some Xmit-errors reported on a switch the VPN's traverse in the DC but it's intermittent and failry low.
We've got a TAC case open and they have been focussing on the packet loss which we had bubbling around the 1-3% mark. This packet loss is not evident at those levels anymore.
The internet is lossy but should small loss affect SD-WAN performance at the level being seen?