Hello,
I have multiple WANs and I'm using them in a PCC load balancing configuration but I noticed that my ISP has set up some sort of burst speed so when I start to download a file I get something like 10x the real speed of the line for a second or two and then the speed drops to the real line speed so I was thinking if it is possible to use that to my advantage.

My idea is to set up the routerboard so that it routes traffic to a specific WAN interface and changes the route to another interface at an interval so that the traffic always flows at the burst speed.

So is this possible in the routerboard? any disadvantages?

Regards

Can this be achieved by `limit` and `dst-limit` of the mangle mark connection rules of the pcc config?
looking at the docs they seem to be useful in my use case but I don't really understand the parameters that well so not sure if that would help

The purpose of allowing higher bandwidth for connections that just started is to provide better experience for interactive services while limiting regular downloads to the contract bandwidth.

Leaving aside the ethical aspects, technically, your approach is unlikely to work unless you have public addresses in your network that are reachable via both uplinks, as the remote server identifies a connection by the client side address and port. So once you switch over to the other uplink, there are two possibilities - either even your request packets will be dropped by the ISP as their source address will not match the interface they emerge from, or they will reach the destination and the server will respond them, but the responses will be sent to the IP address from which the TCP session has been initiated, and thus they will get delivered via the corresponding uplink and throttled.