Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Raspberry Pi Pico does line rate 100M Ethernet

github.com

Post reply on HN
Print view View original

41–50 of 67 posts

Re: Raspberry Pi Pico does line rate 100M Ethernet

#41

Post by gbil »

Hikikomori wrote: post #38
dark-star wrote: post #35

Earlier quoted context omitted.

"Line rate" is "fill the 100Mbit link with 100 million bits each second". Of course the overhead is included in that, since the overhead also goes over the wire

Smallest packet line rate is usually the definition network engineers use when discussing performance of devices.

I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually 2-3 packet size categories. I'm interested on some reference on what you wrote

Re: Raspberry Pi Pico does line rate 100M Ethernet

#42

Post by gonzo »

guenthert wrote: post #40
gonzo wrote: post #37

Earlier quoted context omitted.

This is a lazy definition and won’t get you past “Go” when making network equipment. Why not use 9000 byte “Jumbo” frames? You’ll only need to process 1,383 packets per second to fill the link!

That's actually what NAS vendors do.

RPi Pico NAS at nearly 600Mbps!

What could go wrong?

Re: Raspberry Pi Pico does line rate 100M Ethernet

#43

Post by Hikikomori »

gbil wrote: post #41
Hikikomori wrote: post #38

Earlier quoted context omitted.

Smallest packet line rate is usually the definition network engineers use when discussing performance of devices.

I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually 2-3 packet size categories. I'm interested on some reference on what you wrote

https://www.fmad.io/blog/what-is-10g-line-rate

As the article calls it, the gold standard. If a device is capable of forwarding/switching packets at the smallest packet size line rate on all interfaces at the same time you don't have to think too much about its performance when designing your network. Haven't worked much with hardware for a few years but it was common that Cisco switches were not capable of this.

Re: Raspberry Pi Pico does line rate 100M Ethernet

#44

Post by nsteel »

gbil wrote: post #41
Hikikomori wrote: post #38

Earlier quoted context omitted.

Smallest packet line rate is usually the definition network engineers use when discussing performance of devices.

I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually 2-3 packet size categories. I'm interested on some reference on what you wrote

Vendors I've seen usually use one of a few "standard" packet size mixes e.g. imix. Nobody uses smallest size frames because nobody can hit their headline perf numbers for that, and it's not representative of real-world usage anyway.

https://en.m.wikipedia.org/wiki/Internet_Mix

Re: Raspberry Pi Pico does line rate 100M Ethernet

#45

Post by pantalaimon »

fach wrote: post #22
daymanstep wrote: post #21

Earlier quoted context omitted.

CSMA/CD does use exponential back off, though I'm not sure if anyone is still using it.

This is only for half-duplex ethernet communication so no one apart from some archaic systems.

There is also 10Base-T1 which is a rather recent addition.

Re: Raspberry Pi Pico does line rate 100M Ethernet

#46

Post by Hikikomori »

nsteel wrote: post #44
gbil wrote: post #41

Earlier quoted context omitted.

I'm many years away from such topics but I don't remember this being the case, moreover specs for net equipment was (is) on pps with the details stating usually 2-3 packet size categories. I'm interested on some reference on what you wrote

Vendors I've seen usually use one of a few "standard" packet size mixes e.g. imix. Nobody uses smallest size frames because nobody can hit their headline perf numbers for that, and it's not representative of real-world usage anyway. https://en.m.wikipedia.org/wiki/Internet_Mix

I think this applies more to firewalls used for simple internet connections than switches/routers.

Re: Raspberry Pi Pico does line rate 100M Ethernet

#47

Post by nsteel »

Hikikomori wrote: post #46
nsteel wrote: post #44

Earlier quoted context omitted.

Vendors I've seen usually use one of a few "standard" packet size mixes e.g. imix. Nobody uses smallest size frames because nobody can hit their headline perf numbers for that, and it's not representative of real-world usage anyway. https://en.m.wikipedia.org/wiki/Internet_Mix

I think this applies more to firewalls used for simple internet connections than switches/routers.

I was specifically talking about enterprise/core routers where the packet processing can be non-trivial and small frames hurt performance.

Re: Raspberry Pi Pico does line rate 100M Ethernet

#48

Post by Hikikomori »

nsteel wrote: post #47
Hikikomori wrote: post #46

Earlier quoted context omitted.

I think this applies more to firewalls used for simple internet connections than switches/routers.

I was specifically talking about enterprise/core routers where the packet processing can be non-trivial and small frames hurt performance.

What core routers uses imix?

Re: Raspberry Pi Pico does line rate 100M Ethernet

#49

Post by vardump »

dlenski wrote: post #32

Usually I can grok the significance of almost any item on HN that catches my eye, but here I'm at a loss. Can someone explain why this matters? As far as I can tell, someone has figured out how to send Ethernet packets at a relatively high rate using hardware with very limited CPU. Cool, but what can you _do with that_? If the RPi Pico has the juice to run interesting network _application-level traffic_ at line rate…

RP2040/2350 are IO monsters. You could for example make a logic analyzer that transfers logic data through ethernet.

This "very limited" microcontroller has two cores. Both of them can execute about 25 instructions per byte for generating "application-level traffic". You could definitely saturate a 100 Mbps connection with just one core.

Re: Raspberry Pi Pico does line rate 100M Ethernet

#50

Post by nsteel »

Hikikomori wrote: post #48
nsteel wrote: post #47

Earlier quoted context omitted.

I was specifically talking about enterprise/core routers where the packet processing can be non-trivial and small frames hurt performance.

What core routers uses imix?

Not sure what you mean, but an example of using imix to measure perf of a core router is Cisco 8000 series https://miercom.com/wp-content/uploads/2024/02/Performance-V...
Post reply on HN