Question about gigabit ethernet

CorpX

Limp Gawd
Joined
Mar 1, 2005
Messages
285
Currently, we have DSL and the DSL modem also functions as a 100 Mbit 4 port router.

Here's my question

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In such a setup, will transfer speeds between PCs be gigabit or 100Mbit? I think the DSL modem will still be assigning the local IPs in such a situation, so I'm wondering what speeds would result.
 
PC to PC should be Gigabit speeds if they are all connected to the gigabit switch
 
http://www.hardforum.com/showthread.php?t=1447269

As long as the communication is only going through gigabit devices (two gigabit PCs and a gigabit switch), it will be at gigabit speeds. If the communication includes a 100Mb link, that will be the bottleneck (e.g. plugging a gigabit PC into one of the router's switch ports). The DHCP from the router and the link speeds are completely unrelated - Fast Ethernet vs. Gigabit is done in Layer 1 (Physical) while the addressing stuff from the router is Layer 3 (Network). http://www.webopedia.com/quick_ref/OSI_Layers.asp

mixedlan.png

(Diagram created with Network Notepad)

In this case, the internet connection (green lightning bolt) would be whatever speed your internet connection is, like 1-10Mb. The green link from the modem to the router would be 10Mb or 100Mb, depending on the details of your router's WAN port and your modem's ethernet port. Assuming the router has a 100Mb switch built in, the connection from the router to other devices (the dark gray lines to PC1 and the switch) would be at 100Mb. The light gray connections from PCs 2-4 on the gigabit switch would be at 1000Mb. Just find the slowest link between any two devices, and that will be the speed that they're limited to.

For example, connections from PC4 to PC1 will be limited to 100Mb by the router's switch. If PCs 3 and 4 were both trying to copy files from PC1, they would be sharing the 100Mb link between the switch and router (and also between the router and PC1). Anything going out to the Internet will be limited to your connection speed, as that's the slowest link in the whole network.
 
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