[Server-devel] Network Provisioning

[Stefan Reitz]

> CC: wad at laptop.org; martin.langhoff at gmail.com
> From: wad at laptop.org
> Subject: Re: [Server-devel] Network Provisioning
> Date: Fri, 25 Apr 2008 09:03:53 -0400
> To: stefan_w_reitz at hotmail.com; server-devel at lists.laptop.org
> 
> 
> On Apr 25, 2008, at 8:29 AM, Stefan Reitz wrote:
> 
> > Hi Y'all,
> >
> > On Fri, 2008-04-25 at 14:57 +1200, Martin Langhoff wrote:
> >>
> >> On Fri, Apr 25, 2008 at 2:38 PM, John Watlington  
> >> <wad at media.mit.edu> wrote:
> >> >
> >> > Proposed change to the hardware spec:
> >> >
> >> > From one to four access points may use an simpler switch,
> >> > connected to the server over a 100 Mb/s link. From five to seven
> >> > access points will need a better switch, which provides a 1 GB/s
> >> > link to the server.
> >> >
> >> >  This means that a 1 GB/s interface should be specified for the  
> >> servers.
> >
> > I feel teleported back to my 3-19-08 mail:
> >
> > [...]
> > (I am thinking  server clusters - red hat cluster suite is offering  
> > some nice tools which I never got a chance to use / try - thinking  
> > 3 servers with fail-over and increased performance for clients  
> > (like two servers actually doing something...) would be a starting  
> > point)
> > Birmingham is looking at 49 schools with a total 14,000+ students.
> > [...]
> >
> >>
> >> Theoretically, yes... but perhaps this is a bit over the top. For the
> >> space we are aiming...
> >
> > please define our aim
> 
> Martin was correct in that the aim of this discussion is rural  
> schools in
> Peru.   Birmingham, NYC, and others will require heftier servers.

Where, if not here, should large school environments be discussed? 
This planet has many very large cities, mostly in developing countries, and I hope the XOs will make it there.

> 
> I do dispute any claim that 1Gb/s network interfaces are over the top at
> this point in time.   The cost difference on the manufacturing side is
> around $2.
> 
> >> - the XS services will bottleneck well before saturating 1Gb/s  
> >> traffic
> >> - 'upstream' services that the XS is routing will bottleneck well  
> >> before 1Gb/s
> >>
> >> if we see a 7-AP setup, it will be there to support either a large
> >> number of laptops or a location with obstacles that needs many
> >> antennaes. In any case, it will support laptops mostly peering w
> >> eachother.
> >
> > how about those 14 - 28 AP setups?
> >
> >>
> >> If we are designing for a "client base" of laptops that we actually
> >> expect to saturate 1Gb, then... we need to start recommending a
> >> mid-range server cluster, perhaps a SAN, all costing a few megabucks
> > -->   http://en.wikipedia.org/wiki/Weasel_words
> >>
> >> ;-)
> >>
> >
> > You get pretty decent off-the-shelf hardware for $500 (asus m2n,  
> > athlon x2 xx , 2GB RAM) + cost of storage space) per server.
> > And considering not every deployment is a remote underelectrified  
> > mountain / desert / ... area, this should not be light heartedly  
> > dismissed.
> >
> >> cheers,
> >>
> >> m
> >
> > And I agree with Aaron Huslage that the nature of the AP is going  
> > to be another big hitter. But I really haven't seen the numbers on  
> > the budget yet. A decent (non-WRT54(...)) AP comes for $300 - 450  
> > and is still worth considering.
> 
> 
> Please define decent, and how it differs from "cheap".   We have run  
> into APs that appeared to artificially cap the number of connections  
> to less than 30 (market segmentation ?), but have also tested $50 APs  
> which seem to support 50 users fine.

In the vicinity of another 10+ APs serving 50+ clients each?

> 
> Yes, centrally managed networks of APs are much better.
> Is that the $300-$450 price you quoted, and does that include the  
> controller ?

How to define decent:

* keeping a cap on the spreading of broadcast messages.

* not bailing out under load (and recovering gracefulliy if things go wrong).

* providing working quality of service features (hopefully the XO's
voip / video conferencing client will eventually get off the ground)



This would probably be served with e.g. the cisco AIR-LAP1131AG-A-K9 or 3COM's 3CRWE876075 (or other even pricier products).

(I don't sell any of these, nor do I recieve any incentives for recomending them.)



The WRT54(...) are not known to be aimed at anything above personal home use.
(Ok, I just came across linksys'  WAP54GPE which would be in the $380 range and have the suspicous "54" in it's name, but the reviews are less than encouraging)

If controller for you equals switch: No. But e.g. Netgear's  GS116 or  JGS524 (16 / 24 ports) would probably be sufficient.

> 
> wad
> 

Unfortunately BHM or NYC (...) pose the challenges of business production environments (many clients in overlapping areas) and the equipment manufacturers charge what the customer can pay. Business customer that is. 
I could imagine that a good purchasing department is capable of reducing the price by 30% but I don't see schools or school boards gaining this kind of expertise (or leverage for lack of order volume).

None the less, the investment is IMHO still justified by the reduced down time / latency / overall client experience.


Stefan

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