It's tricky to decide which of these options to play with.The problem is there doesn't seem to be a way to have a gap in the data with Econet -- so if the target network were faster than the source, it'll have to be fully buffered. That is to say, unless the bridge had control of the clock: in which case it could slow down the target network to match the source. It's crude, but maybe that's an option?
There's a whole bunch of good things you can do with a variable speed clock - analysing the station numbers and running it at a speed to suit the slower of the two stations communicating (so two arcs on a short network go at a high speed, but an electron on the same network gets a slow clock as soon as it starts to communicate). The SJ bridge already does a limited version of this to support an MDFS running faster than BBCs (and the source of the fast data being Nexus). You can even go further - you can vary the clock speed within the packet, as the defining speed for the software is typically at the line turnaround and it would be capable of going faster in the middle of the packet. And CRCs that are processed in hardware might as well be sent at higher speed etc.
Conversely, if you want to do the cut-through bridge idea, you really want a constant speed clock: if you can measure it, you can make more informed decisions about when to start cutting through. You don't know the length of the packet so this isn't ideal, but at least you can cut-through immediately if the destination network is slower or same-speed; you could make assumptions about max packet size and start cutting through part way down a packet in the other direction.
The switch/bridge device can potentially get back some performance by allowing more than one packet to be in flight at once. It doesn't want to do store-and-forward as that breaks the 4-way handshake semantics, but two pairs of unrelated stations can communicate simultaneously.
The Pi Pico/RP2040 is potentially a good platform for developing this stuff - a single device can potentially handle 8 connected Econets.
Statistics: Posted by arg — Fri May 24, 2024 10:58 pm