[AccessD] OT: Network speeds

Gary Kjos garykjos at gmail.com
Mon Mar 19 16:45:28 CDT 2012


On my gigabit switch I never see ONLY the gigabit light. I see 100 or
BOTH and I am quite sure that when I looked at the documentation it
said that was how the lights on the switch worked.

GK

On Mon, Mar 19, 2012 at 4:24 PM, jwcolby <jwcolby at colbyconsulting.com> wrote:
> In troubleshooting further, I discovered that if I reboot the VM Server
> (with the 100 mb light lit), as soon as post begins both the gigabit and
> mbit lights on the switch light, IOW it is "both" from the git-go.
>
> I'm not sure what that means actually, other than it isn't a driver issue
> since the drivers (or Windows even) haven't loaded yet.
>
> I also don't know what both lights lit actually means anyway.  That is the
> only machine that appears to do that.  Perhaps the board is bad?  I looked
> through the BIOS for NIC related stuff but all I found was an on/off bios
> switch for the NIC.  The NIC is in the AMD chipset.
>
> I don't even have a gigabit NIC card.  Motherboards just have them now so I
> quit buying them ages ago.  I may go get one just to see if that would cause
> the 100 mbit light to go away.
>
>
> John W. Colby
> Colby Consulting
>
> Reality is what refuses to go away
> when you do not believe in it
>
> On 3/19/2012 2:55 PM, jwcolby wrote:
>>
>> Good article. but what a PITA that brings up.
>>
>> I have my WIFI router / cable modem plugging into the gigabit switch *in
>> the middle*. Does that
>> router tell that entire middle switch to dumb down to 100 mbit? if so then
>> there's my answer as to
>> "why". What is left unanswered is how to get around this. I have lots of
>> internet network traffic in
>> the living area at the front of the house, and I also have internet access
>> in my office upstairs.
>> None of it is "optional", i.e. we need internet at both ends of the house
>> for email at the very
>> least. Web browsing as well.
>>
>> I just crawled under my table up in my office and what I discovered is
>> that the switch under there
>> has one line, going to my Virtual Machine Server which shows the gigabit
>> light and the 100 megabit
>> light lit. I unplugged and moved the cable and both lights followed the
>> cable. I would guess that
>> perhaps the 100 mbit is for a virtual machine.
>>
>> In my server I actually have two NICs and I can assign one of those NICS
>> to support a virtual LAN
>> just for the VMs. However even there those machines have to talk to the
>> internet.
>>
>> What I discovered is that I have a 100 mbit switch down stairs behind the
>> tv. It talks almost only
>> to the UnRaid server in the basement. One would expect that each channel
>> would adapt (flow control)
>> but the article mentioned the transmitting NIC seems to be the object
>> modified. What the article
>> didn't say was whether the NIC stayed at the lower speed or whether it
>> popped back up to the higher
>> rate as soon as possible.
>>
>> My motherboard in the VM server only has a single NIC so if it is being
>> throttled down and then just
>> stays there until a reboot or something...
>>
>> So much to know, so little time. And in this case I do not even have the
>> knowledge to troubleshoot
>> it effectively.
>>
>> John W. Colby
>> Colby Consulting
>>
>> Reality is what refuses to go away
>> when you do not believe in it
>>
>> On 3/19/2012 12:54 PM, Michael Bahr wrote:
>>>
>>> John, for Gigbit to work properly I think **everything** must be Gigibit,
>>> i.e. all network cards, wifi, routers, switches, etc. I think Gigibit
>>> uses jumbo-frames. Otherwise you can have a mixed-mode condition. You do
>>> not mention what kind of router/switch you have,
>>> consumer/business/enterprize. Oh forget enterprize--too expensive. :-)
>>> Some routers/switches may support mixed-mode. Read the link below.
>>>
>>> http://www.smallnetbuilder.com/content/view/30212/54/
>>>
>>> Mike...
>>
>>
>
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-- 
Gary Kjos
garykjos at gmail.com



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