understanding red and interface bandwidth

Hi community,

it seems that I have a major problem understanding the bandwidth of RED-intertface on a Sohps UTM 9.4

I am running a hub-and-spoke setup, where some locations are connected by site-to-site vpn tunnels with a central Sophos UTM 9.4. One of those location is connected using a RED-device.

The central office only got a 2 MBit/s symmetrical internet leased line, which is however fine, since the remote locations are sdmall and are only connection via Citrix's HDX protocol. QoS-rules to avoid congestions are in place.

The remote site using the RED is however connected by LTE gicing it a max download speed of 21 MBit/s.

Although the RED-interface on the UTM is set to assymetrical, and the correct values for incoming and outgoing bandwidth are set, the users only get a little bit more than 2 MBit/s.

Unfortunately, since it is a remote office, I was unable to measure internet speed when connected between the RED and the LTE-router.

So now I am asking: Could it be that the central office's internet speed is realyy a constraint in such an environmnet ?

Regards

Tobias