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I am trying to decipher exactly what is meant by switching bandwidth on tech specs for various switches. I think I understand, but I'm not so sure.

I know that a port on a 10/100/1000 switch can operate at 1Gbps in each direction at the same time in full duplex mode. So that means that each port can have a theoretical bandwidth of 2Gbps. If a 24 port switch has an advertised "switching bandwidth" of 48Gbps (such as this Netgear), is that just normal? Because Cisco seems to be making things confusing with their marketing, eg here.

Does switching bandwidth scale linearly with the number of ports available? I've seen some models with 4-8 ports with much lower figures for switching bandwidth.

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up vote 3 down vote accepted

In short, I would assume it describes at what speed the switch itself can route data between the ports.

If you have a 24 port switch with 48Gbps switching bandwidth, great! Every port can operate at full capacity at all times.

If you have a 24 port switch with 24Gbps switching bandwidth, not as great. Only half of the ports can operate at full capacity or all of them at half capacity (or something in between).

I would assume the second group is the cheaper group ;)

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I was doing a bit of researching, and I guess that's what's meant by "non-blocking". If a switch can handle the theoretical maximum of 2Gbps per port, then it's non-blocking. I think pretty much all rack mountable switches are like that these days since it's become much cheaper to manufacture than before. – agent154 May 28 '12 at 17:31
@agent154: Not exactly. For 1Gbps ports, that's pretty easy today, but the 40Gbps and 100Gbps ports are a lot tougher on switches. – MSalters May 28 '12 at 22:25

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