ethernet VS tokio

After creating the ARP Request packet we need to now create an Ethernet Frame. The Ethernet frame contains fields such as Source and Destination Hardware (MAC) among others. Now, as the communication inside a network is carried out using the MAC Address, we can set the value of destination hardware address field to theMAC Address to which we want to communicate. Learn more about Ethernet Frame here.

You can send raw packets with something like this [1] [2].

I imagine you want to test the approach is software before implementing it in an FPGA.

You can then construct Ethernet frames to be as simple as you like [3].

This question seems like what you might be trying to do [4].

[1] https://stackoverflow.com/questions/12229155/how-do-i-send-a...

[2] https://stackoverflow.com/questions/57133295/how-can-i-liste...

[3] https://en.wikipedia.org/wiki/Ethernet_frame

[4] https://stackoverflow.com/questions/815758/simple-serial-poi...

Ethernet frame structure (https://en.wikipedia.org/wiki/Ethernet_frame)

Some communication does happen at the MAC level, like ARP, but these days it's all done with the expectation that your machine is going to be making use of TCP/IP. So this layer 2(-ish) protocol really just exists to establish the addressing. So the point of a private IP is mainly because all of the typical communication protocols we use expect one. Could you make something work without one? MAC-to-MAC? Yes, that's ethernet traffic, and the Wikipedia page shows the source and destination MACs as part of the structure of the header of a frame.

I find looking at the header structure directly helps me to wrap my head around it. At layer 2 you are dealing exclusively with Ethernet frames which have a number of fields in their header that indicate their source and destination MAC addresses, among other things. These frames are what the switch builds it's CAM table from and it uses that table to forward traffic, and for a layer 2 switch that is the entire picture.

The preamble and SFD (and IPG) are not part of the frame, they are part of the Layer 1 Packet. This is one of the most common Ethernet misconceptions. See Wikpedia's Ethernet Frame article.

Wrong layer. :) This is later two, or the Data Link layer. https://en.wikipedia.org/wiki/Ethernet_frame

Being able to control nondeterminism is particularly useful for testing and debugging. This allows creating reproducible test environments, as well as discrete-event simulation for faster-than-real-time simulation of time delays. For example, Cardano uses a simulation environment for the IO monad that closely follows core Haskell packages; Sui has a simulator based on madsim that provides an API-compatible replacement for the Tokio runtime and intercepts various POSIX API calls in order to enforce determinism. Both allow running the same code in production as in the simulator for testing.

tokio / hyper / toml / serde / serde_json / json5 / console

tokio - An asynchronous runtime for Rust

3. Tokio

The AWS SDK makes use of the async capabilities in the Tokio library. So when you see async in front of a fn that function is capable of executing asynchronously.

Petar is also looking at implementing concurrency the way it is in Go to have a fully functional virtual machine as it is in the spec. This would likely attract more external contributors to developing the VM. One advantage of Rust is that, with the concurrency model, there is already an extensive library called Tokio which he can use. Petar stresses that this isn’t easy, but he believes it’s achievable, at least as a research topic around determinism and concurrency.

Another thing to point out is that async is a thing in Rust. I'm not going to begin to dive into this paradigm in this article, but know it's handled by the awesome Tokio framework.

So I started by using Tokio, a popular async runtime. The docs and samples helped me get a simple outbound TCP connection working. The Rust async book also had a lot of good explanations, both practical and digging into the details of what a runtime does.

Regarding the quote:

> The Original Sin of Rust async programming is making it multi-threaded by default. If premature optimization is the root of all evil, this is the mother of all premature optimizations, and it curses all your code with the unholy Send + 'static, or worse yet Send + Sync + 'static, which just kills all the joy of actually writing Rust.

Agree about the melodramatic tone. I also don't think removing the Send + Sync really makes that big a difference. It's the 'static that bothers me the most. I want scoped concurrency. Something like <https://github.com/tokio-rs/tokio/issues/2596>.

Another thing I really hate about Rust async right now is the poor instrumentation. I'm having a production problem at work right now in which some tasks just get stuck. I wish I could do the equivalent of `gdb; thread apply all bt`. Looking forward to <https://github.com/tokio-rs/tokio/issues/5638> landing at least. It exists right now but is experimental and in my experience sometimes panics. I'm actually writing a PR today to at least use the experimental version on SIGTERM to see what's going on, on the theory that if it crashes oh well, we're shutting down anyway.

Neither of these complaints would be addressed by taking away work stealing. In fact, I could keep doing down my list, and taking away work stealing wouldn't really help with much of anything.

The PHP <-> Rust bindings are provided by https://github.com/Nicelocal/ext-php-rs/ (our fork of https://github.com/davidcole1340/ext-php-rs with a bunch of UX improvements :).

php-tokio's integrates the https://revolt.run event loop with the https://tokio.rs event loop; async functionality is provided by the two event loops, in combination with PHP fibers through revolt's suspension API (I could've directly used the PHP Fiber API to provide coroutine suspension, but it was a tad easier with revolt's suspension API (https://revolt.run/fibers), since it also handles the base case of suspension in the main fiber).