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TOPIC: Uplink ports: When to use em ?

Uplink ports: When to use em ? 11 years 8 months ago #6849

  • SVR
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I have just wired my house with cat-5 using Leviton wall plates in each room wired in 568B fashion.
The other end(s) use RJ-45 wired like a store bought cable ( grn stripe / blu stripe swapped ). These connect to a hub in the attic.

One room has a router & cable modem.

+wall plates
|hub p1|>
+
<p2 router p1>---<modem>
|hub p2|>
+
<comp>
|hub p3|>
+
<comp>
|hub p4|>
+
<comp>
|hub p5|>
+
<comp>

All ports are normal (not uplink). All connecting cables are normal. everything works this way.

But if I understand the concept, I should use hub pU (uplink) to connect to router p2 or router pU to hub p1, right ?

So, two questions ...

Why is this working ?

Which method is best (hub pU -> router p2 or visa versa) ?

To add more confusion, if I insert another hub on one of the comp lines, it works also without uplink.
I thought you *have* to use the uplink to connect hubs (or a crossover)
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Re: Uplink ports: When to use em ? 11 years 8 months ago #6851

  • MezzUp
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I didn't exactly understand you, but most modern switches and NICs are Auto-MDI which means it doesn't matter wether you use straight through or a crossove cable
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Re: Uplink ports: When to use em ? 11 years 8 months ago #6853

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Hmmm, that would explain why it's working ;-)

Any thoughts about which Uplink port should be used (if I decide to switch things around) ?

In theory, a switch will pass all packets to the Uplink port. In this layout, the only packets needed at the router are addressed to the gateway so it should be on a normal port (of the switch), right ?

So it probably is best not to use any uplink port ;-)

Anyway, thanks for the Auto-MDI tip. That was beginning to freak me out :P
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Re: Uplink ports: When to use em ? 11 years 8 months ago #6854

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Glad I could help
In theory, a switch will pass all packets to the Uplink port.
I've never heard that. I thought an uplink port on a switch was the same as a hub? That is, and MDI port instead of the regular MDI-X ports on a switch/hub
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Uplink 11 years 7 months ago #6934

  • TheBishop
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Apart from the 'passing all packets to the uplink port' which I can't comment on, all the crossover/uplink function does is to get you a working link between the two devices. So it doesn't matter which end you use the uplink port at, or even whether you use two normal ports and a crossover cable. I've even seen people fudge their fixed cabling and 'cross over' one of them at the patch panel bit that's not a good idea as it can get very confusing later and introduces inflexibility
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