There is a lot of variety just within PCI cards. Some do full offloading, some push most back to the CPU. The CNR card pushes 100% of the work back to the CPU.

kolderman wrote on 2020-03-28, 21:14:

There is a lot of variety just within PCI cards. Some do full offloading, some push most back to the CPU. The CNR card pushes 100% of the work back to the CPU.

Ah in that case, PCI seems the way to go. Probably an Intel Pro NIC of the time. Thanks!

kolderman wrote on 2020-03-28, 21:14:

The CNR card pushes 100% of the work back to the CPU.

The CNR card typically has the analog interface such as the PHY while the controller is in the chipsets. This does not imply that the built-in Ethernet controller is dumb and push everything into CPU. The built-in Ethernet controllers in Intel/VIA/NVIDIA chipsets have much better offloading capabilities than standalone Realtek RTL8139 PCI Ethernet which has dominated the low-end PCI Ethernet add-in cards.

kjliew wrote on 2020-03-29, 00:52:

The CNR card typically has the analog interface such as the PHY while the controller is in the chipsets. This does not imply that the built-in Ethernet controller is dumb and push everything into CPU. The built-in Ethernet controllers in Intel/VIA/NVIDIA chipsets have much better offloading capabilities than standalone Realtek RTL8139 PCI Ethernet which has dominated the low-end PCI Ethernet add-in cards.

Yeah. Just ordered Intel Pro/100 VE for CNR (why not?) and it seems like the chip provides some offloading. Maybe not as sophisticated as higher level intel chips, but definitely better than 8129/8139.

rkurbatov wrote on 2022-02-10, 21:09:

Yeah. Just ordered Intel Pro/100 VE for CNR (why not?) and it seems like the chip provides some offloading. Maybe not as sophisticated as higher level intel chips, but definitely better than 8129/8139.

the "chip" on Intel Pro/100 VE is just a PHY, not an Ethernet controller. PHY is the analog frontend https://en.wikipedia.org/wiki/Media-independent_interface
MAC (actual Ethernet controller) must be on the motherboard for the CNR card to function.
Looking at wiki and pinouts.ru first version of CNR called A had a proprietary non standard signal protocol between MAC and PHY, and only second one called B allowed manufacturers to use same off the shelf PHY chips as used in everything (switches, network cards). Basically whole "CNR network card is made using $0.5 piece of PCB, $1 chip, $0.3 serial eprom, $0.3 magnetics, $0.1 8P8C socket and a $0.1 steel bracket, AKA a scam to sell you $2 worth of stuff for additional $10 instead of integrating it on the motherboard.

I thought the VE is not a cnr but a proprietary similar to cnr that only work on intel chipsets like 815

Vaudane wrote on 2020-03-28, 21:22:

Ah in that case, PCI seems the way to go. Probably an Intel Pro NIC of the time. Thanks!

I just want to nail this home. This is the correct answer.

Biggest advantage is DRIVERS. Intel still updates drivers to this day. not every day, but you get the point. 2nd in line are 3Com cards (in the 9x era) and realtec based cards are mostly okay. Unless you enjoy dicking around on dead websites for the odd-ball ethernet cards.

Dont be afraid to grab the pci-x gigabit cards. In most cases (Pentium 2 and later) you can just slap in a 64bit card into a 32 bit slot without issue, so long nothing physically gets in the way.

rasz_pl wrote on 2022-02-11, 03:07:

the "chip" on Intel Pro/100 VE is just a PHY, not an Ethernet controller. PHY is the analog frontend https://en.wikipedia.org/wiki/Media-independent_interface
MAC (actual Ethernet controller) must be on the motherboard for the CNR card to function.
Looking at wiki and pinouts.ru first version of CNR called A had a proprietary non standard signal protocol between MAC and PHY, and only second one called B allowed manufacturers to use same off the shelf PHY chips as used in everything (switches, network cards). Basically whole "CNR network card is made using $0.5 piece of PCB, $1 chip, $0.3 serial eprom, $0.3 magnetics, $0.1 8P8C socket and a $0.1 steel bracket, AKA a scam to sell you $2 worth of stuff for additional $10 instead of integrating it on the motherboard.

So CNR is just a MII bus between MAC on chipset and PHY on card? And nothing can be offloaded on that level, except for functionality provided by chipset?

That's why it disappeared quite fast. Something basic moved to the motherboard, and something advanced provided full functionality. Good to know.

But anyway, I want it just because I hadn't it. I've seen hundreds of Realtek PCI cards and none CNR ones. 😀

AMR, CNR and ACR had a sensible role to play in their day, specifically around the time stuff started to get integrated into motherboard chipsets with the AC'97 spec. It was all about compulsory (FCC) certification for modems. That certification took time and was prohibitively expensive. To do it for every model of motherboard was commercially impossible, so instead an absolutely minimal module for the PHY was invented, which would let manufacturers get most of the cost benefit of integrating a frequently-used peripheral without having to get every single board certified. Once that slot was there anyway, additional functionality was offered on it, particularly things that could be integrated but were paradoxically rarely used at the time, like network connections.

The broadband revolution obsoleted the dial-up modem and thereby removed the prime use case for these slots. It also massively increased the percentage of computers being networked (because hooked up to broadband modem via Ethernet) so analog modems disappeared, NICs got integrated onto motherboards and the AMR, CNR and ACR all disappeared.

Given that this was about integrating and cost-cutting, the products were never interesting for enthousiasts building their own system, although if you saw the AMR (Win)modem as a low-level interface to the telephone line, rather than strictly as a modem, you could do interesting stuff with it - but that never took off because of the abandonment of dial-up technology at the time.