CNR would provide a physical layer that connects to the motherboard chipset's integrated LAN. Which is usually fine. At that point 10/100 was pretty solid in general.

Gigabit performance depends a lot on OS as well as CPU. Win9x networking isn't designed for that kind of bandwidth. Win2K/XP is much better and Windows Vista even further improved.

swaaye wrote on 2022-11-17, 20:04:

CNR would provide a physical layer that connects to the motherboard chipset's integrated LAN. Which is usually fine. At that point 10/100 was pretty solid in general.

This is an i815e motherboard so that would be pretty good, as it would save a PCI slot. But I couldn't find any CNR LAN cards, only the useless modem cards, just as I remembered xD

swaaye wrote on 2022-11-17, 20:04:

Gigabit performance depends a lot on OS as well as CPU. Win9x networking isn't designed for that kind of bandwidth. Win2K/XP is much better and Windows Vista even further improved.

Yes Win9x is so slow with any network card, really... but with the right software you could use SCP to transfer files at a reasonable speed and it adds to functionality.

I'm using a modern GNU/Linux for testing, with a 1.2 Tualeron @ 1.6 GHz (133 MHz bus), CAS 2 ram. Pretty stable, prime tested 12-hours without a hiccup. Ram speed (CAS 2 vs 3) has a noticeable difference benchmarking with mprime.

Probably gigabit PCI would work at a higher speed on a different P3-era motherboard, probably the newest kind with DDR ram, but I don't think it would reach 100 MB/s. I'd love to be proven wrong though!

Linux is a different kettle of fish - with top-class networking stack where your hardware will definitely be the bottleneck. Question is how driver module support is for the CNR/i815 LAN solution is.

I've occasionally looked for one to play around with out of pure interest, but for that reason was never willing to pay excessive shipping costs as they always seem to turn up at the other end of the world...

The whole Modem Riser (AMR/CNR/ACR) concept was a very sensible one for a very short period in time. OEMs were pushing for integrating as much as possible to keep the BOM and so costs as small as possible. Around 1999, everyone wanted to get on internet and did that using a modem. Problem was that regulatory authorities (FCC and global equivalents) were very stringent in certifying equipment: every single device with a modem needed time-consuming, extensive expensive testing. So what was needed was an interchangeable thing that didn't need a dedicated controller chip (the most expensive part of a modem) that could be certified, then plugged into everything. Enter the AMR. It was perfectly fit-for-purpose, but obsolete almost as soon as it arrived, due to proliferation of Ethernet-based broadband (xDSL, cable) internet connections starting at the turn of the millennium.

From day 1 there were attempts to do more than just modem, but they were abortive - AMR supported audio too, but every motherboard already had onboard/integrated audio, so it didn't add value and did increase BOM. CNR was an - incompatible - attempt to add LAN to the mix, but it faced the same limitation: you could just as easily add onboard/integrated LAN, so 99% of CNR devices were modems too. Finally ACR added CNR features with AMR backward compatibility. It just added to fragmentation for advanced (LAN) features, and came so late almost no one was using the slots by then.

Realtek 1gbit pci cards are braindead, at least the linux driver comments suggest you need to manually copy buffers around using cpu time because of some descriptor/alignment limitations. 10/100 ones are absolutely fine tho.
Then you have Windows networking bottleneck. The best way to test is a simple FTP transfer, that usually shows true TCP speed with minimal overhead.

Its all moot tho because :
>Another important feature of the 815 is the integration of a fast Ethernet controller directly into the chipset. The integrated LAN controller works with one of >three new physical layer components from Intel and enables three distinct solutions for computer manufacturers. These include:
>-Enhanced 10/100Mbps Ethernet with Alert on LAN technology
>-Basic 10/100Mbps Ethernet
>-1 Mbps home networking

dionb wrote on 2022-11-17, 22:13:

The whole Modem Riser (AMR/CNR/ACR) concept was a very sensible one for a very short period in time. OEMs were pushing for integrating as much as possible to keep the BOM and so costs as small as possible. Around 1999, everyone wanted to get on internet and did that using a modem. Problem was that regulatory authorities (FCC and global equivalents) were very stringent in certifying equipment: every single device with a modem needed time-consuming, extensive expensive testing. So what was needed was an interchangeable thing that didn't need a dedicated controller chip (the most expensive part of a modem)

I have to disagree. Afaik CNR LAN is just a PHY chip, and AMR/CNR modem is just a solid state DAA and ADC/DAC AC’97 audio codec IC correction, AMR only requires DAA, reusing AC97 codec already on the motherboard.
In case of CNR you save whole ~$1-2 in BOM on MAC.
in case of AMR/CNR modem you save ... nothing correction ~$1-2 in BOM on AC97 codec, because software modems were already a thing and were build in exact same way, solid state DAA + audio codec chip. Imo this was intels 'clever' idea of selling OEMs on extra addons they could be upselling their customers on. Implement our thing and you could become a modem/network card vendor overnight!!1

With the margins on consumer systems, USD 1-2 in volume can make a big difference. It's no coincidence that these things only turned up in low-end high-volume systems. They were very popular at Packard Bell (where I worked at the turn of the millennium) from introduction until end of modems being standard in PCs. I recall a bigger price difference though for FRU stock, more like USD 4 or 5.

I ran a CNR modem in my P4 rig in the 2000s. I didn't need it by then, but my OCD wouldn't allow me to leave the slot unpopulated....

dionb wrote on 2022-11-19, 12:27:

With the margins on consumer systems, USD 1-2 in volume can make a big difference. It's no coincidence that these things only turned up in low-end high-volume systems. They were very popular at Packard Bell (where I worked at the turn of the millennium) from introduction until end of modems being standard in PCs. I recall a bigger price difference though for FRU stock, more like USD 4 or 5.

From what I remember in early 2000 those AMR/CNR abominations were same price as cheapest soft modems and network cards in retail. Im sure Dell/HP/PB could use them in bulk contract deals as almost free bonus addons, but for end consumers they made no financial sense. For consumer in Poland 2001 Motorola soft modem was $25 and generic 10/100 PCI Lan $12, cant find any AMR/CNR addon prices because not a lot of price sources are left. Just checked Computer Shopper 2001 https://archive.org/details/ComputerShopper_2001-12/mode/2up and noname Modem $15, 3Com V.90 $22, Lan $9-11.
There was also exactly one CNR addon in whole magazine:
56K CNR Modem, Internal, Bulk, save your PCI slot & utilize the CNR Slot DFCNR $9.95

So consumer could save whole $5 on a $10-15 modem, not exactly great deal when buying $800-1500 computer.

Saving USD 5 with no negative consequences is something I would have done. Particularly after shelling out a lot of money on the core components, anything I could save was welcome. That would have been maybe four beers at the time. Ah, the good old days 😉

But these never were a retail thing, nor were they intended to be. Interestingly, just as it was becoming a moot point as everyone was moving onto broadband anyway, the Linmodem community (Linux support for these software modems) was turning the old 'they're not a real modem' argument on its head, instead saying you should see them as generic software-defined access to the telephone line, with the AMR as most pure implementation. Looking at what later became of software radios and SDN, that could have delivered some interesting stuff if anyone had taken that point 5 years earlier. But they didn't, so these things basically remained a way for OEMs to increase their profit margins a little bit.

dionb wrote on 2022-11-20, 18:15:

Saving USD 5 with no negative consequences is something I would have done.

Me too, but there are clear drawbacks here. Instead of universal PCI lan card/modem you can resell or reuse in another computer you get something eternally linked to your Intel motherboard.

dionb wrote on 2022-11-17, 22:13:

I've occasionally looked for one to play around with out of pure interest, but for that reason was never willing to pay excessive shipping costs as they always seem to turn up at the other end of the world...

I also see it that way. It would be cool to have it but I'm not willing to pay a fortune for it.

rasz_pl wrote on 2022-11-18, 16:39:

Realtek 1gbit pci cards are braindead, at least the linux driver comments suggest you need to manually copy buffers around using cpu time because of some descriptor/alignment limitations. 10/100 ones are absolutely fine tho.
Then you have Windows networking bottleneck. The best way to test is a simple FTP transfer, that usually shows true TCP speed with minimal overhead.

It's indeed an RTL8169SC. One day I'll do some testing on Windows XP but I doubt the performance will be any better.

Thanks for relating the story of the little known CNR slot.

Fun fact: The interface for the modem card for the PcChips M748LMRT is called DAA. I thought I'd throw it in there. It's not a standard per se but yet another fancy short-lived modular modem interface.

DAA means "Data Access Arrangement" and is a frontend for analog telephone network 😀
https://www.smart-energy.com/wp-content/uploa … em%20design.pdf
https://www.vishay.com/docs/83866/appnote66.pdf
"Typical DAA functions include high-voltage isolation,
on/off-hook control, pulse dialing, line transfer, ring
detection, loop-current detection, and caller ID detection."

This is what AMD/CNR modems were build with - a DAA chip connected to onboard AC97 codec. PCChips didnt do "standard" Intel AMR/CMR because they were too cheap for proper edge connector 😀 pins are cheaper. Later PCChips board had AMD and CNR connectors.