[161078] in North American Network Operators' Group
Re: 10 Mbit/s problem in your network
daemon@ATHENA.MIT.EDU (Warren Bailey)
Mon Feb 25 12:48:29 2013
From: Warren Bailey <wbailey@satelliteintelligencegroup.com>
To: Owen DeLong <owen@delong.com>
Date: Mon, 25 Feb 2013 17:47:55 +0000
In-Reply-To: <F67344F2-D9F5-4149-AD9A-7B34860429C8@delong.com>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
If you want to see something pretty amazing, check this out..
http://www.popsci.com/science/article/2012-06/twisting-signals-vortex-resea=
rchers-beam-25-terabits-data-second
These guys got close to 100 bits/hz using Orbital Angular Momentum in addit=
ion to the normal Spin Angular Momentum. There is a picture out there of th=
e I/Q showing the constellation, which to me looks like the future of commu=
nications systems. In my world, if you could offer 5 bits/hz or higher you =
would very likely be able to retire on your own island. Space segment for s=
atellite systems can cost as much as 175k for 36MHz, so giving someone a 20=
x bandwidth increase would be an absolute game changer. Don't be surprised =
if you see the 802.11 guys trying to figure out how to make OAM work, it wo=
uld essentially solve the worlds bandwidth problems at nearly all frequenci=
es.
From: Owen DeLong <owen@delong.com<mailto:owen@delong.com>>
Date: Mon, 25 Feb 2013 08:56:05 -0800
To: User <wbailey@satelliteintelligencegroup.com<mailto:wbailey@satellitein=
telligencegroup.com>>
Cc: Frank Bulk <frnkblk@iname.com<mailto:frnkblk@iname.com>>, NANOG <nanog@=
nanog.org<mailto:nanog@nanog.org>>
Subject: Re: 10 Mbit/s problem in your network
N has a number of advantages=85 Better spread, the ability to take advantag=
e of polarization, better use of MIMO, and IIRC, a better encoding scheme t=
hat allows denser constellation points (more bits per signaling element).
N on 5Ghz takes advantage of the increased bandwidth of the 5Ghz channel wh=
ere A merely replicated G on 5Ghz for all practical purposes.
Owen
On Feb 25, 2013, at 8:42 AM, Warren Bailey <wbailey@satelliteintelligencegr=
oup.com<mailto:wbailey@satelliteintelligencegroup.com>> wrote:
I should probably know this, but doesn't N just spread better and have the =
ability to send receive on multiple polarizations? As an RF engineer I shou=
ld probably know this, but I can't think of many people in my industry who =
really care about 802.11_. I really don't even use wireless in my house, th=
ough it's generally due to overcrowding the spectrum in populous areas.
From my Android phone on T-Mobile. The first nationwide 4G network.
-------- Original message --------
From: Owen DeLong <owen@delong.com<mailto:owen@delong.com>>
Date: 02/25/2013 8:38 AM (GMT-08:00)
To: Frank Bulk <frnkblk@iname.com<mailto:frnkblk@iname.com>>
Cc: NANOG <nanog@nanog.org<mailto:nanog@nanog.org>>
Subject: Re: 10 Mbit/s problem in your network
Correct. However, while A is 5Ghz (only), it's not significantly better tha=
n G.
The true performance gains come from 5Ghz and N together. N on 2.4Ghz has
limited benefit over G. N on 5Ghz is significantly better.
Owen
On Feb 24, 2013, at 8:56 PM, "Frank Bulk" <frnkblk@iname.com<mailto:frnkblk=
@iname.com>> wrote:
> The IEEE 802.11n standards do not require 5 GHz support. It's typical, b=
ut
> not necessary.
>
> Frank
>
> -----Original Message-----
> From: Owen DeLong [mailto:owen@delong.com]
> Sent: Sunday, February 17, 2013 2:07 PM
> To: Jay Ashworth
> Cc: NANOG
> Subject: Re: 10 Mbit/s problem in your network
>
>
> On Feb 17, 2013, at 08:33 , Jay Ashworth <jra@baylink.com<mailto:jra@bayl=
ink.com>> wrote:
>
>> ----- Original Message -----
>>> From: "Scott Howard" <scott@doc.net.au<mailto:scott@doc.net.au>>
>>
>>>> A VPN or SSH session (which is what most hotel guests traveling for
>>>> work will do) won't cache at all well, so this is a very bad idea.
>>>> Might improve some things, but not the really important ones.
>>>
>>> The chances of the average hotel wifi user even knowing what SSH means
>>> is close to zero.
>>
>> {{citation-needed}}
>>
>>> As an aside, I was sitting in JFK airport (terminal 4) a few days ago a=
nd
>>> having a shocking time getting a good internet connection - even from m=
y
>>> own Mifi. I fired up inSSIDer, and within a few seconds it had detected
>>> 122 AP's...
>>
>> Yup; B/G/N congestion is a real problem. Nice that the latest generatio=
n
>> of both mifi's and cellphones all seem to do A as well, in addition to
>> current-gen business laptops (my x61 is almost 5 years old, and speaks A=
).
>>
>
> I think by A you actually mean 5Ghz N. A doesn't do much better than G,
> though
> you still have the advantage of wider channels and less frequency congest=
ion
> with other uses.
>
> Owen
>
>
>
>
