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Old 19th December 2011
alpha202ej alpha202ej is offline
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Default Recommendation for PCIe NIC (1-port)

Hi guys,

I was wondering if anyone could recommend a good NIC for my OpenBSD box which we are currently using for PF. I have maxed out my PCI slots and need a PCIe 1 Gbit NIC (Single Port).

Thanks!
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Old 19th December 2011
ocicat ocicat is offline
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Quote:
Originally Posted by alpha202ej View Post
I was wondering if anyone could recommend a good NIC...
Your best bet is to take the time to search through the archives of the project's official misc@ mailing list. A quick search yielded the following:

http://marc.info/?l=openbsd-misc&w=2&r=1&s=gbit+nic&q=b

However, poking about using different search criteria is in order.
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Old 19th December 2011
shep shep is offline
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I did not get any thing that directly addressed PCI express or PCIe in the archives so I tried a different tact and tried searching for the newer bus technology with openbsd on google and found this:
Calomel.org

And pulled this from the site.

Quote:
PCI Express is a newer technology which elevates bus bandwidth from hundreds of megabytes per second to many gigabytes per second. This allows a single machine to support multiple gigabit ports per interface card or even multiple 10 gigabit ports. The PCIe link is built around dedicated unidirectional couples of serial (1-bit), point-to-point connections known as lanes. This is in sharp contrast to the earlier PCI connection, which is a bus-based system where all the devices share the same bidirectional, 32-bit or 64-bit parallel bus. PCIe's dedicated lanes allow for an incredible increase in bandwidth.

Lets take a look at some of the new PCI Express (PCIe) interface speeds compared to the older PCI bus. These values were collected from the PCIe Wikipedia page:

(type) (bus speed) * (bus width) / 8 = (speed in Megabytes/second)

PCI 66 MHz * 32 bit / 8 = 264 MB/s
PCIe v1 2500 Mhz * 32 1 bit lanes / 8 = 250 MB/s (minus 20% overhead)
PCIe v2 x1 5000 Mhz * 1 1 bit lane / 8 = 500 MB/s (minus 20% overhead)
PCIe v2 x2 5000 Mhz * 2 1 bit lanes / 8 = 1000 MB/s (minus 20% overhead)
PCIe v2 x4 5000 Mhz * 4 1 bit lanes / 8 = 2000 MB/s (minus 20% overhead)
PCIe v2 x8 5000 Mhz * 8 1 bit lanes / 8 = 4000 MB/s (minus 20% overhead)
PCIe v2 x16 5000 Mhz * 16 1 bit lanes / 8 = 8000 MB/s (minus 20% overhead)
PCIe v2 x32 5000 Mhz * 32 1 bit lanes / 8 = 16000 MB/s (minus 20% overhead)
PCIe v3 x32 5000 Mhz * 32 1 bit lanes / 8 = 19700 MB/s (minus 1.5% overhead)

We highly recommend getting an interface card supporting PCIe due to their high bandwidth and low power usage. Note, PCIe version 2.x has a 20% bandwidth overhead which PCIe version 3.x does not. PCIe 2.0 delivers 5 GT/s (GT/s is Gigatransfers per second), but employs an 8b/10b encoding scheme which results in a 20 percent overhead on the raw bit rate. PCIe 3.0 removes the requirement for encoding and uses a technique called "scrambling" in which "a known binary polynomial" is applied to a data stream in a feedback topology. Because the scrambling polynomial is known, the data can be recovered by running it through a feedback topology using the inverse polynomial and also uses a 128b/130b encoding scheme, reducing the overhead to approximately 1.5%, as opposed to the 20% overhead of 8b/10b encoding used by PCIe 2.0.
He does not specifically mention nic chipsets but you could possibly email the author for recommendations.

Last edited by shep; 19th December 2011 at 08:22 PM. Reason: Formating
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Old 22nd December 2011
shep shep is offline
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Out of curiosity I looked at some of the faster PCIe cards - they are pricey
Newegg Gbps Nics
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Old 3rd January 2012
Logan Logan is offline
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Use something which is stable. Try to get re(4) on a PCIe bus.
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