Maximum Bandwidth through gigabit switch
This seems like a simple question, but I can't find a definitive answer for it. I have four devices connected to a Gigabit switch as in this diagram:
Can I get the full GBit bandwidth from A-B simultaneously as C-D are maxing out their link? Or, in general, do they "share" the bandwidth through the switch?
61 Answer
With a well-designed Ethernet switch, it's possible to get the full port speed into each port and the full port speed out each port, all simultaneously (switch ports are full-duplex).
A switch designed to guarantee it can do this will be marketed has having an aggregate throughput of:
2 * (#-of-ports) * (speed-per-port)This is sort of double-counting because the data going out any given port must have come in some other port, but this double-counting has become a de facto industry standard marketing practice.
So in your example of a 4-port Gigabit Ethernet switch, it would be marketed as having 8Gbps of bandwidth.
Unfortunately, it wouldn't surprise me if most 4-8 port GigE switches are cheap consumer crap that can't do that and thus wouldn't be marketed as such.
