switch and half-duplex lines ?

Hello !

I don't understand that in the following situation how come each host can have 10 Mbps ? I mean the router that serves internet connection has just only one wire to Switch, how can each host can have 10Mbps internet connection ?

******* Switch is connected with Router, and this Switch has 10 hosts connected to it with half-duplex. Switch serves 10Mbps. Router serves internet connection. *******
Reply to
jh3ang
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A 10Mbps connection means the standard definition on how the two devices exchange information. This doesn't necessarily mean that the actual data rate is rellay this high. It is similar to electricity: one circuit has a fuse with 10A, the other may have 16A. This doesn't mean that the actual flow is that high, it is usually a lot smaller.

Regards, Christoph Gartmann

Reply to
Christoph Gartmann

They don't. They have a 10 Mbps link to the switch. The router I assume also has a 10 Mbps link to the switch that traffic from all 10 hosts gets funnelled through. Its Internet connection then become a bigger bottleneck limiting traffic flow from all 10 hosts. TCP then reduces throughput to some degree based on end-to-end latency etc.

As a side note ... if using a switch configuring links as half duplex is a bit of a waste.

BernieM

Reply to
BernieM

Greetings,

Each of the 10 hosts has a road capable of passing 10 cars at a Time, however all those roads meet at an intersection to travel down a MAIN road that can only pass 10 cars at a time. All 100 cars cannot access the MAIN road at the same time, so they have to QUEUE up to pass though the intersection to access the MAIN road. This is exactly what a Switch does, it sequences access for 10 dedicated ports to 1 SHARED port by Queuing traffic. If all 10 Hosts wanted access at EXACTLY the same time, then they would only be able to get the equivalent of 1Mb of bandwidth each.

The PHYSICAL path is 10Mb, but it is extremely rare that you would find 10 x 10Mb ports all wanting 10Mb at EXACTLY the same time. In real terms the road is almost NEVER full of traffic, so the 10Mb Shared port is shared out by Multiplexing the traffic from the other ports. This multiplexing is handled by a "store and forward" approach.

BTW, if your Switch truly is an Etherswitch and not a Hub, then to get the best possible performance you should be using a FULL Duplex setting for all hosts that can support that. A Hub can only do Half-Duplex.

Cheers.............pk.

Reply to
Peter

All hosts most likely are not streaming a full 10mb worth of data out either. most are small amoutns of data at anyone time. Most PC's will not push near that amount of data out with normal web browsing.

We have a few 1000 hosts on our netowrks all going out a 20mb connection, not using 25 percent of that bandwidth at any peak time.

Reply to
MC

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