adding 1G ethernet to a 100M network

[CLIFFORD ILKAY]

On 07/29/2010 12:01 PM, James Knott wrote:
> D. Hugh Redelmeier wrote:
>> My home ethernet is all 100M.
>>
>> I'm accumulating a few devices with 1G interfaces.
>>
>> I assume that I can add a 1G switch, connect it to one of my 100M
>> switches, and connect the nearby 1G interfaces to the new switch.
>>
>> Does this cause any problems? Are there better ways to do this?
>
> Switches will automagically detect and configure for the correct speed.
> You could have a mix of 10M, 100M and 1G on your switch without problem.

There is a caveat. At a colo facility recently, we installed a gigabit 
D-Link switch figuring that it would "just work". The network 
performance of any of the machines connected to that switch was abysmal 
even though the colo facility had provided us with a 100Gbit/s 
connection to their Cisco switch. Apparently, consumer grade switches 
like the D-Link and others cannot auto-negotiate to the highest possible 
rate if the other end isn't configured to auto-negotiate. The other end 
was configured to be 100Gbit/s, full-duplex. The D-Link would fall back 
to 10Mbit/s, half-duplex, thus explaining the poor network performance. 
Replacing the D-Link with a Cisco (not Linksys) switch and setting it to 
100Mbit/s, full-duplex was the solution.
-- 
Regards,

Clifford Ilkay
Dinamis
1419-3266 Yonge St.
Toronto, ON
Canada  M4N 3P6

<http://dinamis.com>
+1 416-410-3326
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