Lan switch

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JoPo
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Lan switch

Post by JoPo » Tue Dec 19, 2017 5:18 am

Hi.
I've got a technical question for lan expert, if there is any...

In my house, I have the 'livebox' which is connected to internet. It is also a Gbits router.
My home studio in a small outbuilding and there is 2 pc, both wired to a Gbits switch which is connected to the livebox with an ethernet cable. I don't use wifi, only cables. It looks like that :
lan.jpg
lan.jpg (34.66 KiB) Viewed 1125 times
I don't find any answer to this question : are the data of the 2 pc connected to the switch transmitted directly between them or do they have to go through the livebox router ?
> > > > > > > > > > > > --- Musica --> here ! ---< < < < < < < < < < < <

Ripper
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Re: Lan switch

Post by Ripper » Tue Dec 19, 2017 6:06 am

Do a traceroute from one pc to the other, like this:
tracert xx.xx.x.xxx (ip of the other pc to check)

I am expecting only one hop saying something like:

1 <1 ms < 1 ms < 1 ms "nameofpc2 [XX.XX.X.XXX]
Trace complete.

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astroman
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Re: Lan switch

Post by astroman » Tue Dec 19, 2017 6:09 am

A switch does only what it's name implies: it switches data packets between cables.
To where packets are directed is the job of a router (currently your LiveBox), which attaches the proper path to the data.
You could run such a router on one of the PCs, though... but it's a tricky thing, highly unrecommended ;)

If you want the 2 private PCs even more private, the best solution imho is to exchange the switch by a switching router.
You gain additional control about your PCs internet connection that way (depending on that devices software capabilities).
Again only recommended with very high security concerns, it's a complex task.
Did this recenntly with a professional Lancom device... or rather tried... and failed miserably at first attempt :oops:
(Lancom provides full network control up to the finest detail by a software that's more or less a Scope equivalent for networking, just lacking the graphic interface...)

cheers, Tom

w_ellis
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Re: Lan switch

Post by w_ellis » Tue Dec 19, 2017 6:49 am

Simple answer to the question is: probably yes, they talk to each other directly through the switch, as that's the path of least resistance. It's like water flowing :)

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valis
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Re: Lan switch

Post by valis » Tue Dec 19, 2017 10:39 am

There's no real reason to segment your network with a router unless you're worried about guests on the housePC or have an open wifi. Also, you can get managed switches which will enable the same thing, without needing all the features a router offers.

However, I think what you're really wanting to know is if the gigabit switch between the 2 PC's in the studio is affected by the HousePC, and as long as the communication is ONLY between the 2 studio computers the HousePC traffic won't be routed across the switch. Packets only flow to the intended destination with switched & routers, it's hubs that send packets to every port on the device (as they are passive and not 'packet switched' by an IC chip).

(edit: w_ellis replied while I was typing, so my response is semi-redundant and pedantic now :D )

jksuperstar
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Re: Lan switch

Post by jksuperstar » Tue Dec 19, 2017 11:41 am

To expand on Vlais' comment, your localized studio switch will send packets directly between pc1 and pc2, so it is lowest latency and highest speed between the two PC's. Those packets should not go all the way back to your router to communicate between the studio PC's.

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astroman
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Re: Lan switch

Post by astroman » Tue Dec 19, 2017 12:36 pm

... and as long as the communication is ONLY between the 2 studio computers the HousePC traffic won't be routed across the switch.
sorry, my bad above ... lost scope :D
the default gateway of the LiveBox is only engaged when the destination is outside of the local subnet

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JoPo
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Re: Lan switch

Post by JoPo » Tue Dec 19, 2017 1:19 pm

Thank you all for those clarification ! :)
It's what is needed : that pc1 & pc2 exchange data go directly between them. After posting the question, I read that, as Valis said, router attaches destination to packets, so there is no reason for the data to go to the livebox router when there is a shorter way though the switch.
> > > > > > > > > > > > --- Musica --> here ! ---< < < < < < < < < < < <

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