There is no HUB data flow from collector hub to tunnel hub happening, both the alarm and QOS queues takes garbage value, stuck with that and no actual data is getting cleared from the "queued" collector hub.
Release : 20.3
Component : UIM - HUB
From the analysis of the transfer rate which was checked between the collector hub and the tunnel hubs using the callback check_transfer it was evident that the transfer rate on the link is very low. Which is ranging between 18 to 29 kbps.
The callback "check_transfer" will create a data block using the hub details and some block memory and send it to the destination hub, here it is sent from the collector hub towards the hub1 and hub2 hubs. The hub1 and hub2 will calculate the time taken for the transfer. The transfer speed is calculated by dividing the size of data by time taken for the transfer. This calculation for hub1 and hub2 is boiling down to 18-29 kbps.
As this rate of transfer is very low for the hub receiving 1000 qos messages per second, the transfer is blocked from the collector to tunnel hub. When the bulk size is reduced then it startes moving. If the transfer rate is low, before the big packet is sent the request is getting timed out. That is the reason why the packets with lower size is moving while the big sized ones are blocked.
From the screenshots of the local hub and collector hub, you can see that the transfer rate is more and so is the QOS speed between the hubs.
So, it is suggested to check the bandwidth between the collector hub and tunnel hub and provide higher bandwidth for the link.