Things That Affect NIC Cards' Performance?

Question

Folks,

I have a laptop and a tower. And I use EtherCAT (through Ethernet port) on both. But I notice that if I unplug my cables on the tower, I loose a lot of frames, where as in the laptop I may not lose any frames at all when I disconnect an ethernet cable.

I have all my NIC set up to 100Mbps Full-Duplex, since this is the most optimal configuration for EtherCAT.

What are the factors that can make this work better on my laptop an not as good on my tower?

Can the following items affect? (you can add more items to the list as well)

1) The processor (I have an ARM board that uses two PRU to handle Ethernet related data, and I barely loose frames when there is an error...like a disconnected cable)

2) RAM?

3) Cache?

Answer 1

I'm not familiar with EtherCat, but I can definitely tell you that all network cards are not created equal when it comes to handling data loads and error conditions.

The chipset in your laptop most likely happens to have a better integration to the internal local bus of the computer and thusly the functions of the CPU, due to everything being on one board, whereas the desktop could probably benefit from upgrading to a server grade network card, like an Intel. Or possibly a motherboard with a different built-in chipset.

The better network cards have on-board processors and/or features to make them more fault tolerant, and less of a burden to the computer that is hosting it. They also often come with better drivers, as well.

The computers' RAM and cache don't necessarily correlate to how well it transmits data on a network, unless there is an actual bottle-neck, and the system simply cannot send or receive data until it is ready again.

Answer 2

At the NIC level, possible delays include: a PHY that's slow to equalize itself to the cable; a missing or disabled carrier-detect interrupt; driver layers that delay or debounce the carrier-detect status received from the interface. System concerns that can introduce significant delays include: loss and reestablishment of configuration and other state (DHCP, NetworkManager, Internet access testing, etc); and other services that block network access until completely initialized (antivirus, firewall, sync, etc).

Also, it's my completely unscientific anecdotal recollection that some chipsets (Realtek?) are slower to go from plug to play than others.

In any case, if you need quicker recovery from cable faults, you might test different network cards in the PC. Or, you could also try to prevent cable faults through link aggregation.