On Fri, Oct 22, 2010 at 10:33 AM, Simon Billis <simon@xxxxxxxxxx> wrote:
> Hi Rudi,
>
>> Does anyone have, or know of a comparison chart of the different
>> network adapters, i.e. 1GB / 10GB, Infiniband, etc. And if possible
>> with a few top brand NIC's and switches listed as well.
>>
>> I would like to see, for example, what the max throughput is of a 1GB
>> NIC (and this could probably differ from PCI to PCIE-x1 to PCIE-x4),
>> and 10GBE. Different switches would probably also have different
>> ratings, but could a layer 2 switch & layer3 switch deliver the same
>> performance for example?
>>
>> Basically I need to know what upload / download speeds I should be
>> getting from the different networks, set aside other options like CPU
>> / RAM / disc IO / etc.
>
> If you exclude the host capability to deliver data to the interface and also
> the ability of the host to assemble and disassemble packets, then the speeds
> will be dependent on the switches capability to handle the packet size and
> numbers of packets arriving at an interface in a specific time period. You
> should expect wirespeeds (minus the overhead of the Ethernet frame and the
> IP frame) for most switches with usual packet sizes (below 1500 bytes) i.e.
> the usual (if there is such a thing) packet size, provided that you're not
> flooding the interfaces with very small packets and your switch is set to
> store and forward. If your switch is able to cut and forward which is a must
> for jumbo frames to be handled quickly, then you can also expect close to
> wirespeeds for any frame size. Cut and forward switches are expensive but
> are a must for storage networks if you're interested in low latency
> switching.
>
> Layer 3 switching is basically routing done on a switch and therefore
> increases the latency slightly to a lot as the switch has to decode the
> layer 3 information and make a decision based on that as opposed to the
> outer layer 2 information.
>
> Due to the many factors affecting network speeds, most switch manufacturers
> specify the switch capability/capacity in backplane bandwidth, maximum
> packet numbers switched per second and memory available for store and
> forward. As soon as one of these limits is breached then the performance
> will take a hit and this hit can be a big one.
>
> I'm sorry that I can't be more helpful and provide you with what you're
> after, but I hope that this has answered some questions for you.
>
> Rgds
>
> Simon.
>
>
>
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>
Thanx Simon, this was rather useful.
So, if I have a layer2 & layer3 switch at my disposal then I won't
really notice much differences between them, right? The one SMC switch
I have at the office can handle 200MB/s, according to the spec sheet.
But, can a normal 1GB NIC handle the same throughput?
--
Kind Regards
Rudi Ahlers
SoftDux
Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
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