[kwlug-disc] CAT6 - worthwhile?

unsolicited unsolicited at swiz.ca
Sun Nov 24 11:04:26 EST 2013


John - it is common on a switch that the switch backplane, or switch 
fabric, has a capacity equal to or greater than all of the ports talking 
at once. Thus if one device is talking to another, and another is 
talking to another, all devices will be talking their full bore - 'cause 
the backplane capacity so much exceeds any individual port's capacity. 
That's why when buying a switch, peek at the backplane capacity. If it 
is something less than the sum of the ports, move along to the next product.

- unlike a wi-fi AP (router) where the one radio has a particular 
capacity and within that capacity round robins (by packet?) each wi-fi 
client in turn. Thus, each client gets 1/(# active clients) bandwidth, 
tops. (And '# active' is more than is apparent, as all devices maintain 
a heartbeat - to know when the network is gone. Ethernet has the same, 
but it is less frequent, less onerous, and at need. ['Who has' arp's.)

As I said - if multiple switch devices are talking to the same 
destination, then each sender will only get half. (Not so if they are 
talking to different destinations, and so get full (client) bore.)

The point being that copper will always be individually faster than any 
single wi-fi client / AP connection. Wi-fi speeds being what they are, 
I'd say it's also true that collectively any single copper connection 
will have greater throughput then all wi-fi clients together. 
(Individual ethernet wire speed > total AP speed.)

Nature of the wire (copper) over wi-fi (radio) beast.

On 13-11-24 10:10 AM, John Johnson wrote:
> Re: "each device on copper has a full speed dedicated connection"
>
> AFAIK not necessarily
> While with point-to-point copper there is no "ether" as there is with
> wifi the hardware internals in a router or switch may include a common
> bus. i.e. shared media inside the box.
>
> I doubt that two servers (A and B) streaming data to two workstations (C
> and D) as in A to C and B to D at the same time through a common router
> / switch would each enjoy the maximum throughput that would be available
> if only one server was streaming.
>
> AFAIK CATx ratings were primarily the fire ratings as opposed to data
> throughput. (Wikipedia here I come).
> And the toxicity mentioned earlier is due to materials designed to
> suppress fire traveling along a cable from a flame source to another
> area in a building.
>
> John VanO and others may be able to clarify.
>
> Apologies: Paul (2013-10-26) says the entire thread[s] is[are] worth
> reading. Maybe I should do so - before my next comment.
>
> JohnJ
>
> On 2013-10-26 17:40, unsolicited wrote:
>> No. To expect it is unreasonable.
>>
>> Each device on wi-fi halves the throughput for each device on the
>> wi-fi. So your 300Mbps, which you will never achieve (below), goes to
>> 150 as soon as you put something else on. Like a printer. Even just a
>> device turned on has a hearbeat / continuously scans for connectivity
>> and takes up some of the time slices.
>>
>> And wi-fi (let alone usb over esata) has much more protocol overhead
>> such that data throughput is seriously degraded. Add in checksumming
>> and encryption and it gets even worse.
>>
>> - each device on copper has a full speed dedicated connection.
>> (Doesn't mean two devices on a switch trying to talk to the next hop
>> beyond the switch get it - even gigabit switch to switch is still only
>> gigabit. BUT - each device will get full speed when it's got the wire,
>> and each device will get through what it needs to do faster. If the
>> two devices are talking to each other, then they talk full speed to
>> each other, and something else can talk full speed up the line to the
>> next switch - simultaneously. In such a scenario, each device would be
>> doing much less better than 1/4 full speed, wifi.)
>>
>> 300Mbps is only achievable through dual-band *5GHz* - not always
>> achievable with other networks around.
>>
>> Just as I noted its ludicrous that not everything comes with Gbps NICs
>> these days, even fewer come with 5GHz, let alone dual, wi-fi radios.
>>
>> So, sorry to say, your shiny new 5GHz router, connected to your 2.4GHz
>> single band printer has bought you ... nothing.
>>
>> Even throwing down a network cable to the printer, at 10Mbps, will
>> gain you a 15x speed increase, IIRC. And every other wi-fi device will
>> gain from not competing with the printer any more.
>>
>> - just like turning off wi-fi on your phone will do the same.
>>
>> I ran speed tests when I got the last laptop - maybe it's useful.
>> http://kwlug.org/node/750
>>
>> In the end, the only thing that matters is - is it fast enough for you?
>>
>> In the end, wi-fi is a fantasy. Do backflips to figure out copper if
>> you have to - it's worth it. 'cause there will always be another wi-fi
>> device coming along to chew up what wi-fi bandwidth you have - like
>> your phone (no copper connection equivalent), or someone else's,
>> needing the internet ... 'just for a moment.'
>>
>>
>> On 13-10-26 11:26 AM, John Kerr wrote:
>>> My current router at work is rated at 56mb. I just purchased a new
>>> router
>>> rated up to 300mbps. Great except the Internet comes in at 25mbps.
>>>
>>> I have purchased a new wireless printer as well.
>>> So I bought the new router so that any printing jobs will be done
>>> faster.
>>> Am I in my right mind on this?
>>>
>>> To me it is the last 50 feet that are important. Will there soon be a
>>> wireless Internet service that will give us the speed that our
>>> routers are
>>> capable of?
>>>
>>> Cheers
>>>
>>> John
>>>
>>>
>>>
>>>
>>> On Sat, Oct 26, 2013 at 2:30 AM, unsolicited<unsolicited at swiz.ca> wrote:
>>>
>>>> OK, but my real basic question is, to what end?
>>>>
>>>> Gigabit has even now not permeated enough of the world. (Why any laptop
>>>> still comes with 10/100 is beyond me). Even my USB 3.0 / gigabit
>>>> adapter
>>>> can't saturate the gigabit.
>>>>
>>>> Future proof for what (copper wise)?
>>>>
>>>> If the world is going tablets and phones - that's wifi, not copper.
>>>> Even
>>>> if you have copper and an AP at each room for wi-fi devices to
>>>> connect to,
>>>> no amount of devices on that wi-fi will ever saturate the gigabit -
>>>> wi-fi
>>>> will never be that fast. (?)
>>>>
>>>> Home wise, I'm not prepared to even put out for multi-run bonding - the
>>>> equipment required at each end is extraordinarily expensive (for
>>>> home). I
>>>> don't imagine it's any different for 10Gps CAT6 ethernet, let alone
>>>> fibre.
>>>> And if it's fibre we get to, the copper run, 5e or 6, isn't going to be
>>>> useful.
>>>>
>>>> So if most things can't saturate gigabit now, and fibre is going to
>>>> need
>>>> another run anyways if we get there ... future proof for what (sorts of
>>>> beasties / media)?
>>>>
>>>> I'm not objecting to 6 over 5e, I just wonder ... for what?
>>>> - especially given the more expensive equipment required at each switch
>>>> point, and the tighter bend and untwist limits for 6. I'd bet every
>>>> home 6
>>>> installation breaks at each jack / switch / 5e device<->jack cable.
>>>>
>>>> If you've bent a cable, what, more than 30 degrees, or untwisted a
>>>> pair,
>>>> or untwisted pairs more than 1/2 inch - you've just made using cat 6
>>>> pointless.
>>>>
>>>>
>>>> So my real question was ... what's coming that might need 6 over 5e?
>>>>
>>>> In house HD video distribution?
>>>>
>>>>
>>>> On 13-10-25 04:57 PM, John Van Ostrand wrote:
>>>>
>>>>> Personally I think any new installation should use Cat 6. It's only
>>>>> marginally more expensive than 5e but could future-proof your house a
>>>>> little more. That said 5e will perform very well in a house since runs
>>>>> tend
>>>>> to be short and will work in cases where Cat 6 is supposedly
>>>>> required. The
>>>>> way I look at it is that the time spend installing is the the most
>>>>> expensive cost (even when done yourself) so using a higher grade cable
>>>>> future-proofs so you can avoid pulling everything out and re-doing
>>>>> cable.
>>>>> Sometimes I'll use 5e jacks because those are easier to replace.
>>>>>
>>>> .
>>>> .
>>>> .
>>>>
>>>>
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