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Re: Home network router does not forward LAN traffic



Paul Johnson wrote:
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> On Mon, Jun 09, 2003 at 11:43:40AM -0500, Keith G. Murphy wrote:
>
>>I take minor issue with this blanket statement: a switch doesn't really
>>gain you anything unless you're getting enough traffic for collisions,
>>and takes away your ability to monitor everything (tcpdump, ethereal)
>>that's going on from one point, given that you have two or more other
>>computers having conversations of interest.
>>
>>Please correct me if I'm wrong.
>
>
> Switch also buys you full-duplex Ethernet.

That's a really good point.


> You get far better performance for about the same
> price with a switch.  Why anybody would use a hub if they can at all
> avoid it in this day and age is beyond me.
>
> Packet sniffing tools are best suited for running on the same segment
> as a router, or the router itself, anyway.

Mmmm, what if I have two machines that are on the same LAN segment, having a conversation of interest, but I want to run my sniffer from, say, a Linux server on the same segment? (Router shouldn't even come into play in a situation like that).

Don't get me wrong: I agree with your larger point. In almost every
situation, I'd probably take a switch over a hub as
well. At the prices of even a few years ago, things were different.

This was an interesting discussion I saw:
http://www.ccontrols.com/pdf/Issue%209.pdf

They introduce the issue of latency, which I had thought might be an
issue with switches as well, but wasn't expert enough to address.  The
relevance of that issue would probably be very application-dependent.




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