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Posted By: michael_d Ethernet Switching question - 01/27/11 06:07 PM
I'm re-wiring my communication hub where I have all my home network, cable and phone lines dropped into the house. It's been a mess for years and I have finally got the motivation to do something about it.

Regarding the home network, I have 14 cat 5 hard wired lan locations. They all route to the patch block. I then use patch cords from the block to the router or switch. My router is a Linksys E3000. I also have a Cisco 8 port switch. The switch uses one of the E3000's ports, so I have a total of 11 ports. Not enough. I don't want to move cables around anymore, and believe it or not, I'm always doing just that. I figured I'd swap out the 8 port switch with a 16 port switch, or add a second switch. Would it be preferable to add a second switch or replace the 8 port with a 16 port? If I add a second switch, does it plug into the first switch or the router? I'm just looking for some basic does / dont's before I go shopping. It's a rarity to find what I actually want, so I need to be flexible and make whatever is available at the local Radio Shack work.
Posted By: Ken.C Re: Ethernet Switching question - 01/27/11 06:09 PM
Replace the switch. If you get a second switch, for simplicity, I would plug it into the first switch. You COULD plug it into the router's built in switch, and that would probably work, but then you're trusting the router not to do anything funky with its switchports.
Posted By: oldskoolboarder Re: Ethernet Switching question - 01/27/11 06:58 PM
Yup, replace the switch w/ a 16 port and let it do the switching vs the router. You could stack another 8 port but it'll be cleaner w/ just a 16 port.

Plug one port of the 16 port into the router and you'll be good. If you get an unmanaged switch, it won't be too expensive. Don't get a hub.
Posted By: michael_d Re: Ethernet Switching question - 01/27/11 07:11 PM
OK, just for clarification.... If I can not find a 16 port switch, just get a second switch and plug it into the existing 8 port switch? Depending on what they have, and the switch dimensions, I may have to go with the second switch. I only have 2.25" to work with, as that is my shelf height.

I was also reading up on the E3000 and realized it has a USB port for a USB storage device. I'm contemplating just plugging my HP Home Media Server into that verses using the Lan. Anyone tried this before?
Posted By: Ken.C Re: Ethernet Switching question - 01/27/11 07:12 PM
That would work, yes.

Plugging the media server into the USB port on the E3000 will not work.
Posted By: michael_d Re: Ethernet Switching question - 01/27/11 07:27 PM
Figures.....

So is it better to use the switch(s) for all the hard wired things, verses plugging things into the router and the switch(s)?
Posted By: Ken.C Re: Ethernet Switching question - 01/27/11 07:28 PM
Just from the standpoint of being elegant. I suspect that in practice, it makes very little difference, as long as the things on the router's built in switch can still talk to the things on the dedicated switch.
Posted By: jakewash Re: Ethernet Switching question - 01/27/11 09:48 PM
I have 3 PC Lan lines plugged into my router which has 4 ports, the 4th port is feeding an 8 port switch where I have 5 more lines and one of those lines I have another 8 port switch (located in my HT center) which feeds all the HT gear. I have had no issues what so ever running this way.

Having written that down, I guess I should try running the HT switch directly off the router just to see if the Xbox works even better this way, not that it has had any problems so it would be hard to verify any benefit.
Posted By: ClubNeon Re: Ethernet Switching question - 01/27/11 09:51 PM
You may see a millisecond or so faster latency when all the devices are on the same backplane.
Posted By: michael_d Re: Ethernet Switching question - 01/28/11 02:12 AM
What's a backplane?
Posted By: ClubNeon Re: Ethernet Switching question - 01/28/11 03:08 AM
Think of it as the part of the switch that ties the ports together. When you leave one switch and move to another, you're operating on a different backplane.

But the better way to phrase my initial comment is to say, latency within one switch will be the tiniest bit better than the latency between two switches.

Also the backplane throughput is usually higher than any individual port. So you can have multiple conversations all at full speed in one switch, but if multiple devices on one switch are trying to talk to multiple devices on another, they'll all have to go through the bottle neck of the connection between them. (This usually isn't an issue until multiple servers are involved.)
Posted By: SRoode Re: Ethernet Switching question - 01/28/11 12:49 PM
Originally Posted By: michael_d
OK, just for clarification.... If I can not find a 16 port switch, just get a second switch and plug it into the existing 8 port switch? Depending on what they have, and the switch dimensions, I may have to go with the second switch. I only have 2.25" to work with, as that is my shelf height.


Here's one that has 16 ports and is only 1.7" tall:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817111012
Posted By: michael_d Re: Ethernet Switching question - 01/28/11 10:44 PM
Thanks for all the help fellas. The local RS had a Cisco 8 port switch like the one I already had. I hooked each switch to my router and put the devices that talk to each other on the same switch. Now all LAN jacks in the house are hot and ready for use. It's probably just wishful thinking, but I believe things are running a tad more reliable.
Posted By: ClubNeon Re: Ethernet Switching question - 01/28/11 10:48 PM
I think you should conduct a double blind study before making claims like that. laugh
Posted By: michael_d Re: Ethernet Switching question - 01/28/11 11:05 PM
LOL smile

Well, at least my wireing LOOKS better. I forgot how much a PITA building patch cables is. That and I think my vision is getting worse. Those little wires are a lot harder to keep in order now than they were before.
Posted By: CV Re: Ethernet Switching question - 01/29/11 06:04 AM
I need to redo the new ethernet jacks I just put in the basement. I apparently did something wrong on both of them. Oops! But yeah, I've always just bought my patch cables from Monoprice because they're cheap, and I don't like making more cables than I have to.
Posted By: ClubNeon Re: Ethernet Switching question - 01/29/11 06:08 AM
I knew I had arrived, when I no longer had to make Ethernet cables, I could just assign someone to the job.

Of course now when I try to make them, they only work about 50% of the time, it takes me 15 minutes per end, and they look like crap.
Posted By: jakewash Re: Ethernet Switching question - 01/29/11 06:36 PM
I like making my cables, just to have them the exact length I need, nothing more nothing less. It makes cable organizing a little easier without any extra wire to worry about looping etc.
Posted By: ClubNeon Re: Ethernet Switching question - 01/29/11 09:07 PM
Did you know with gigabit and higher, it's against spec to make patch cables the exact length you need? The issue is with short cables.

I found this oh HP's site, but it is noted in other places too:

Quote:
It is possible that short cables will not meet requirements due to the impact of Return Loss.

For example, if a cable is 110ohms in impedance and it is plugged into a port with impedance from 100ohms at 1MHz to 85 ohms at 100MHz, reflections may occur because the cable has almost no attenuation.

Multiple reflections may result in this scenario, possibly resulting in standing waves that build in strength until the signal at the receiver is overwhelmed.

Therefore, it is necessary for a cable assembly (.5m or 2.5m) to meet Return Loss, Near End Crosstalk, and the other specifications set forth in the IEEE 802.3ab 1000BASE-T standard.

Cables under 2.5m have strict requirements to length. They basically have to be of multiples at to not promote standing waves. You have to know the wavelength of the signal, based on the propagation rate of electrons in that particular cable, at a particular frequency. You don't want the cable to be of a length that results in waveform peaks standing at the ends of the cables, else they'll be reflected back by the receiver (because it doesn't attenuate the signal enough) and cancel out other arriving signals.

Under 0.5m it's possible for the reflections to move all the way up the cable and reflect again from the sending side. This causes true standing waves, and will make communication at speed impossible.

Once a cable hits about 2.5m it'll offer enough attenuation of it's own, that combined with the receiver there won't be enough energy to cause interference reflecting back up the line.
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