Shared Internet access in Finnish housing cooperatives

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This is part one of a longer post on co-operative network activity in
Finland. The Finnish model differs from the way Internet services are
provided in most other counties. Information on Finnish co-ops has never
before been available in English. Here I have tried to put together all the
relevant information and experience.

  1 Networking in housing co-ops - HomePNA?
  2 Router issues
  3 Cabling issues - Ethernet on phone wires
  4 Wireless networking

This message has been cross-posted to several newsgroups. General follow-ups
to news:comp.networking.connectivity.


*** *** ***

The beginning - Operator-driven networks

The first Finnish in-house networks were built in the late 1990's when
construction companies began installing structural cabling in new apartment
buildings. An Ethernet LAN was used to provide Internet access to residents.

This brought external service providers in to the in-house network. In this
business model the operator (telco) would sell the the service directly to
to the resident.

Sometimes the building would be connected to the service providers network
by fiber-optic cable. The fiber would be placed at an early stage of
construction. The newly formed housing cooperative would pay the full cost
of the cabling work as sign-up fees for the Internet service. The agreement
between the co-op and ISP would not allow the co-op to buy Internet service.
Instead it allowed the ISP to take over the internal wiring and monopolize
the network. The service provider was free to price the service as they
pleased. The co-op could not abandon the agreement as it meant loosing their
large sign-up fees.

This model did bring residents fast Internet access. It did not however
bring down the cost of access as the service was always priced at or above
the price of slower fixed access alternatives. The monthly fee for fast
Ethernet access in these houses is around EUR 50 with little change in
sight.

HomePNA

A new technology, HomePNA was introduced to in-house networks by
the Internet operator Jippii (now Saunalahti). Originally Home Phoneline
Networking (HomePNA) was marketed in the US as a way of building
home networks by utilizing the multiple existing phone sockets in the house.
In Asia the technology was adapted for ISP use with the introduction
HomePNA 1.1 switches.
http://www.homepna.org/products/#mdu

In an in-house HomePNA network a stack of HomePNA switches is placed in
the central telephone wiring closet of the building. Each apartment is
connected to one port on the switch using the same twisted pair that carries
telephone traffic to the apartment.

Internet connectivity is provided by one (or more) ADSL or G.SHDSL
connections.

Operator-run HomePNA networks reached their peak popularity by the end of
2003. In that year most landlords owning apartment blocks, including
"council housing", made agreements with ISPs to market HomePNA services to
tenants at a price of around EUR 35 a month.

The last year has seen a steady decline in popularity of ISP run HomePNA
networks.

 1. A sharp decline in ADSL prices and increase in speeds has made HomePNA
    service uncompetitive against ADSL and cable modem connections starting
    at EUR 19,50 a month.

 2. The business model is unworkable. An infrastructure like an in-house
    network needs "monopoly protection", not market competition. In the
    worst case, one housing cooperative might have two competing HomePNA
    networks installed in the same wiring closet, both networks providing
    service to 2 - 3 customers.

Also one problem is that often the operator providing HomePNA service is
also providing ADSL service in the same area. These operators are unwilling
to push HomePNA prices below ADSL prices.


Cooperative networks

In 2000 housing cooperatives in Finland started building their own HomePNA
networks. In this model the housing cooperative would own the networking
hardware and pay for the Internet connection.

In early networks only those residents interested in the fixed Internet
connection would take part in the costs. A subscription fee was set up and
collected monthly by the housing cooperative, along  with the maintenance
fee and any other extras for services like the weekly sauna or parking
space. The cost of hardware and installation was covered by the fee in about
two years.

In these early networks about 50% of residents were connected with monthly
fees at around EUR 7.

Some of the first networks were set up in the Helsinki neighborhood of
Maunula in an government initiated project:
http://www.sitra.fi/eng/index.asp?DirID=68&DocID=4248

Internet access to everyone

Newer networks have adopted a different model. All apartments are connected
to the network and Internet service is provided without any extra fee. At a
minimum Internet-service can be provided at around EUR 1 per month with
around EUR 100 per apartment in initial investment costs.

Not having to connect and disconnect individual apartments greatly eases the
maintenance of the network.

In houses with free Internet access network usage has reached a level of 85%
of apartments.


The future of HomePNA

With "Full Rate" ADSL connections at 8/1 Mbps becoming available to
consumers at a price of EUR 45 and to housing cooperatives at EUR 115  the
limited speed (1 Mbps) of HomePNA 1.1 has become a bottleneck.
To lock the key "heavy users" to the cooperative network faster speeds must
be available. Construction of new HomePNA-based networks now seems to have
come to a standstill.

HomePNA 2.0 at 10Mbps proved to be too prone to cross talk so no switches
are available. HomePNA 3.0 could provide a speed of 100Mbps but the switches
have yet to reach European markets.

At the same time the price of compact ADSL DSLAMs (switches) has dropped to
almost the same level as HomePNA switches, at around EUR 50 per subscriber.
The problem with ADSL is its ATM foundation, which causes unnecessary
configuration issues in an otherwise purely Ethernet-based network. VDSL
would provide better Ethernet compatibility and higher speeds, but the
standards are immature and hardware is incompatible.

Ethernet would provide the best alternative, but usually the wiring is
missing. Finnish housing cooperatives are now facing a tough technical
choice between rewiring for Ethernet and adapting ADSL or VDSL technology
for in-house networks.


Security

Security in an in-house network requires that users cannot communicate
directly through the LAN using local IP-addresses or LAN-protocols.
All traffic must pass through a router and be based on public IP-addresses.
The technique to achieve this is to use "port isolation" in the Ethernet and
HomePNA switches. This feature is available in all switches targeted for
the MDU-market.

In-house networks usually share one public IP-address among all users. The
NAPT router isolates  the house network from the Internet and provides a
built in firewall.


Finnish national policy

The Finnish national "Broadband Strategy" emphasizes competition to the
detriment of  infrastructure. The aim is to utilize the existing coper base
of the telephone network to its fullest. In this model each user will have
an individual subscription with a profit driven telco.

Virtually no encouragement is given to cooperative networks or even in-house
networks.
http://www.laajakaistainfo.fi/english/index.php

The opposition, the "fiber party" is largely concentrated in the
Swedish-speaking districts of Ostrobotnia. These people believe in
the importance of infrastructure; fiber-optic Ethernet to every house!
http://www.seutuverkot.net (in Finnish)


Housing in Finland

Most Finns live in apartment blocks. Finland has the second highest
percentage of  apartments in Europe after Spain. Also, a large proportion of
Finns own their apartments. Most apartment houses are organized as housing
cooperatives. The first housing cooperatives were built in Finland around
1900.

     Some of the first Finnish Housing cooperatives are located in the
     Katajanokka neighborhood in Helsinki:
      - http://www.photofora.com/eugene/Jan2003/helsingfors03/index_18.htm
      - http://www.codeman.fi/photo/katajanokka.jpg

Finnish writers often translate the Finnish word "asunto-osakeyhtiö" as
"housing company". The term "housing cooperative" is more accurate as the
form of incorporation of Finnish cooperatives is identical with those in the
US.  In fact, the housing cooperative model was brought to the United States
by Finnish immigrants.

     "The first true cooperative development in the United States was
      started in 1918 by a group of Finnish artisans-the Finnish Home
      Building Association in Brooklyn, New York. "
       - http://www.coophousing.org/HistoryofCo-ops.pdf
       - http://www.findarticles.com/p/articles/mi_m0254/is_4_59/ai_68704399


*** ***
Vocabulary

Housing cooperative
  "Housing cooperatives are a form of homeownership where individuals own
   shares or memberships in a corporation that owns or controls the land and
   buildings that provide housing. The ownership of a share entitles one to
   occupy a unit within the cooperative."
   http://www.coophousing.org/glossary.shtml

Council housing
   (British term) Social housing owned by the city or municipality.

MDU
   Multi-Dwelling Unit

In-house network
   A LAN connecting apartments in an apartment block and providing Internet
   access

Internet connection sharing
   In English parlance "connection sharing" is often used to refer to
   sharing your Internet connection between multiple computers. In this
   text it refers to sharing one WAN connection and possibly one IPv4
   address between multiple subscribers.

Operator
   In the US often referred to as "carrier". A large telco offering
   telephone and ISP services.

Euro (EUR)
   The European Currency Unit, now rated at about US $1.32 to one Euro.


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 2: Router issues]

Bandwidth-sharing problems

Early HomePNA networks suffered from bandwidth-sharing problems.
In an shared Internet connection bandwidth usage between different users
may differ by over one thousand fold. The heaviest traffic is caused by file
sharing and other p2p-programs.

Without any bandwidth limitations or priorization two or even one BitTorrent
user can disable a network and block net access to all neighbors. In an
asymmetric ADSL-connection saturation of the uplink will cause the free
capacity of the downlink to become unusable. Network latency (ping) grows
to over 1 second, practically freezing all other traffic.

ISP:s and housing cooperatives took very different approaches to solving the
problem:

In ISP-run networks the built in bandwidth limitation features of HomePNA
switches were taken into use. Per user bandwidth was throttled down to a
minuscule 128 or 256 kbps.

Cooperative networks wanted to provide each user the full capacity of the
network. Artificial restrictions were disliked. The solution was user
education. Network activists would monitor network traffic, advise neighbors
on proper usage of p2p-software and even temporarily disconnect users who
failed to follow the guidance.

Technical solutions

Luckily purely technical solutions have become available to the bandwidth
sharing problem in the form of traffic shapers. One useful alternative is
the FreeBSD-based firewall distribution m0n0wall with an easily configurable
traffic shaper:
http://www.m0n0.ch/wall /

A Finnish company, Staselog also produces a traffic shaper for cooperative
in-house networks:
http://www.staselog.fi/en/products/index.html

Functions of a traffic shaper:
  1.Delay outgoing traffic so the uplink is newer saturated.
  2.Prioritize interactive traffic.
  3.Recognize p2p-traffic and set to lowest priority.
  4.Give each user an equal share of the usable bandwidth.


Routing with one public IP address

A shared Internet connection will typically use only one public IPv4
address. A router has to perform Network Address Port Translation (NAPT)
between the internal network and the Internet. Normally NAPT blocks all
users from running servers on their PC:s. This is a problem for p2p
applications and may block VoIP services altogether.

A solution is to open a fixed set of port mappings in the router. A set of
ports is allocated for each apartment. Also a set of fixed private addresses
is allocated for each apartment.

Normal users use DHCP to get their IP addresses in the private network. If a
user wants to run a server or a p2p program in active mode, he configures
his PC to use his fixed private address. The set of open ports will be
mapped to this address.

Example:
 - address 10.10.10.157 is reserved for apartment 157
 - ports 51570 - 51579 are mapped to address 10.10.10.157 in the
   private network.

A general configuration of the router can be made that can serve any shared
residential network.  When using m0m0wall this configuration takes the form
of an XML file that can easily be distributed. (Hope to make this available
after some more editing :-)


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 3 Cabling issues - Ethernet on phone wires]

"Helsingin Alueverkkoyhdistys" (Helsinki Neighborhood Networking
Association) is a group of local volunteers and activists with the
altruistic aim of providing "free"¹  Internet access to everyone.

The ultimate goal is to build community owned fiber-optic networks in
residential neighborhoods. Equally important is an open network of wireless
access points. We believe that universal free and open WLAN access is only
possible, if its backed up by an solid infrastructure of shared wired
networks.

The first stage is to build in-house networks in the apartment blocks and
housing cooperatives. Only when we reach a critical mass of  in-house
networks can we start connecting them into neighborhood networks. Housing
cooperatives are important also in the sense that they can easily be
persuaded to give away the free bandwidth needed for the open wireless
coverage.

    ¹ Free in this case means free as in "free lunch"; there is no such
      thing. Someone will have to pay for the service, or better yet
      build the infrastructure that provides the service. The idea is to
      make Internet access a basic infrastructure like streets, electric
      lighting and running water, available to everyone in need of it.
      This infrastructure should be provided by the same people who
      provide these basic services, in most cases the property owners.


Activity has been greatest in two new Helsinki neighborhoods, Ruoholahti and
Pikku-Huopalahti. These neighborhoods consist of  prefabricated concrete
apartment blocks built mainly in the early 1990's with anywhere between 30
and 170 apartments each.
 - http://www.kaupunginosat.net/ruoholahti/kuvagalleria/kuvagalleria.htm
 - http://www.saunalahti.fi/asyhd/kuvplahti/1/kuvat.html


Ethernet everywhere!

From the start the aim has been for higher speeds, thus the focus on
Ethernet technology.

It was felt that if the slow but popular HomePNA technology would be used
for in-house networks, it be a serious hindrance to fiber-optic neighborhood
networks. The limited bandwidth that can be delivered by HomePNA can always
be served by ADSL or other technologies over coper.

Also the focus has been on finding cheap or "zero-cost" solutions for
Ethernet. Housing cooperatives may be willing to invest more heavily, but in
Helsinki all new neighborhoods are mixed neighborhoods with both
resident-owned co-ops and city-owned social housing. The technical solutions
should be so cheap that they can be adopted by council houses with very
limited budgets.

Add-on cabling

The standard way of rewiring houses in Finland has been to use diamond
drills to pierce floors and walls. Heavy-duty aluminum profile conduits are
installed in stairwells to house new cabling. In apartment buildings this
effort was only taken up in conjunction with other renovations, like
renewing the electrical wiring.

Rewiring for the sake of Internet access had not taken up. The only
residential buildings where the effort was made where student dormitories.
The costs would be around 400 euros per apartment. We started looking for
cheaper, lighter alternatives.

Telephone and central antenna cables to apartments are typically enclosed in
20 mm plastic tubing. This would leave space for an other cable in the same
conduit. Also, there should be no need to remove existing telephone wire to
provide the additional Ethernet access.

Initially there was a great distrust that new wire could be pulled alongside
in the same conduit. The only reference was an undocumented 1995 effort to
rewire the dormitories of the Helsinki University of Technology with Cat-5
cable. This was done by student volunteers.

The first houses were rewired in 2003 by volunteer residents. When it was
established that the technique can be utilized, this approach was also taken
up by a large wiring contractor. Several houses with hundreds of apartments
have been wired with a 100% success rate.

Inside the apartment the Finnish legacy telephone socket in one room  is
replaced with a new faceplate with RJ11 and RJ45 connectors. The cost
estimate for  this type of "add-on" wiring is about ? 150 per apartment.
Success requires that the original construction is up to standard.

Horizontal access

Horizontal telephone cabling in Finnish houses is often done with direct
burial cable. There is no horizontal conduit connecting the splices in
different stairwells. Even worse, a housing cooperative might consist of
several detached buildings separated by an asphalt covered courtyard.

In a prototype house fiber-optic cable was used to connect the
Ethernet-switches in the different buildings. Volunteer residents dug up a
ditch for the underground conduit connecting the buildings. Later experience
has shown this effort to be unnecessary; Finnish telephone cable has proven
its ability to carry 100Base-TX Ethernet for over a hundred meters.

The structure for the in-house Ethernet network in a large apartment block:

   1. Place one 24-port Ethernet switch near each stairwell, preferably
      in the electricity or central antenna closet. Usually the Scotchlok
      splice for the telephone wiring is located in this same space.
   2. Pull new Cat-5e cables from the closet to each apartment.
   3. Use free pairs in the direct burial telephone cable to connect the
      Ethernet switch to the central telephone wiring closet at 100 Mbps.
   4. Place the router and central switch at the telephone wiring closet.

Using Cat-3 telephone cable

New Finnish houses built after the year 2000 usually have structural
cabling, that is separate Cat-5e cables for Ethernet and telephone with
RJ-45 connectors. Older houses houses only have cabling for telephone.
Although it is not widely publicized, Finnish telephone cable from the
1990's has a Cat-3 rating.

Houses built after 1995 usually have three twisted pairs serving each
apartment. It has turned out to be quite a simple task to convert the
cabling to Ethernet use. Originally Finnish legacy telephone sockets are
installed with only one pair connected. This leaves two pairs free for use
by Ethernet. The transformation consists of exchanging one legacy socket for
a RJ-11 / RJ-45 combination faceplate and resplicing the Ethernet-pairs so
that only one socket is connected.

The biggest problem for high speed traffic is the Scotchlok splices used to
connect different parts of the telephone cabling. These are not made to
Cat-3 standards. Practical tests however have shown the connections not to
be a problem. Most installations have worked flawlessly even at higher
speeds of 100 Mbps.

Distances over 100 meters do not seem to pose a problem either. Zero error
operation has been observed in telephone cable at
 - 100 Mbps for over 100 meters
 - 10 Mbps for over 150 meters

The trick in running 100Base-TX over Cat-3 telephone cable is to only run
one Ethernet link in one cable. This way cross talk between pairs is
minimized.

Giving up fixed-line telephone

Houses built before 1994 usually only have two pairs, in the form of a
twisted star quad, serving each apartment. Using these pairs for Ethernet
traffic poses two problems:

1. Star quad has an impedance of 120 ohms, which differs from the twisted
   pair impedance of 100 ohms.
2. Using both pairs for Ethernet means that the resident would have to give
   up fixed line telephone service.

In practical tests the impedance mismatch between the pull to the apartment
and the multi-paired trunk cable has shown not to be a problem. 10Base-T
works reliably.

Giving up the fixed phone may not be a problem. Most voice has already "gone
mobile" i.e. moved to mobile phones. The remaining fixed voice traffic is
fast moving to VoIP over the Internet. New programs like Skype and VoIP
gateway service to consumers has made this move possible.

In a survey of residents in a potential conversion site 83% of residents
wanted fixed Internet access. Only 45% required fixed telephone service.
This means that over half of the apartments could be converted to Ethernet
with about 30% needing ADSL or VDSL service.

Filtered solutions for POTS + Ethernet

It may also be possible to run POTS and Ethernet simultaneously on the same
two twisted pairs. Ethernet would occupy the higher frequency band over POTS
on the same pair. Splitters or filters would be used in each end to separate
the two types of traffic.

A company in the US, Energy Transformation Systems, makes filters for this
purpose.
http://www.etslan.com/ethernet.php

A Finnish company H.Vesala Ltd. also makes a similar filter, although for
ADSL use.
http://www.vesala.fi/english/products/adsl_splitters.html

A slightly different implementation is provided by etherSPLIT.
http://www.ethersplit.com /


(Follow-ups to news:comp.dcom.cabling and news:comp.dcom.lans.ethernet.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Re: Shared Internet access in Finnish housing cooperatives


Hi Petri,

Nice project and thank you for sharing your details here. I just had some
comments on that. See my 2cents below.

Petri Krohn wrote:



> [Part 3 Cabling issues - Ethernet on phone wires]


> Add-on cabling

> The standard way of rewiring houses in Finland has been to use diamond
> drills to pierce floors and walls. Heavy-duty aluminum profile conduits
> are
> installed in stairwells to house new cabling. In apartment buildings
> this
> effort was only taken up in conjunction with other renovations, like
> renewing the electrical wiring.

Aluminum burns like crazy, even in alloys. Especially installed vertically
in risers, where convection makes a great job of bringing fresh oxygen
into the burning area. Besides, it is more expensive than almost any other
material used for a conduit. I don't think aluminum alloy made a great
choice for riser conduits.

> Finnish telephone cable has proven
> its ability to carry 100Base-TX Ethernet for over a hundred meters.

It's a shame such great telephone cable is not available in other parts of
the world!

> The trick in running 100Base-TX over Cat-3 telephone cable is to only
> run
> one Ethernet link in one cable. This way cross talk between pairs is
> minimized.

To run one cable per one Ethernet link is not a trick but a norm. Except
that the cable should be CAT5 and higher.

At any rate, it looks like you guys threw a dozen of well-established
industry standards out the window and attempted to establish your own. Did
you give your fire safety authorities a change to take a look at your
cabling? I'm especially concerned about those aluminum riser conduits.

--
Dmitri Abaimov, RCDD
http://www.cabling-design.com
Cabling Forum, color codes, pinouts and other useful resources for
premises cabling users and pros
http://www.cabling-design.com/homecabling
Residential Cabling Guide
-------------------------------------




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Re: Shared Internet access in Finnish housing cooperatives



> Aluminum burns like crazy, even in alloys. Especially installed vertically
> in risers, where convection makes a great job of bringing fresh oxygen
> into the burning area. Besides, it is more expensive than almost any other
> material used for a conduit. I don't think aluminum alloy made a great
> choice for riser conduits.

It seems that in Finland fire safety has never been a big issue as in the
US. Most newer buildings are reinforced concrete, older brick and mortar.
The few steel constructions are mostly from the 1990's.

> At any rate, it looks like you guys threw a dozen of well-established
> industry standards out the window and attempted to establish your own. Did
> you give your fire safety authorities a change to take a look at your
> cabling? I'm especially concerned about those aluminum riser conduits.

Using aluminum risers is not our way of doing things, it is the standard
practice used by everyone else.

>> Finnish telephone cable has proven its ability to carry
>> 100Base-TX Ethernet for over a hundred meters.

> It's a shame such great telephone cable is not available in other parts of
> the world!

I don't really think telephone cable is that much different in different
parts of the world. All decent cable has twists. The lesson is that you do
not really know how good the cable is until you have tried it in practice.

>> The trick in running 100Base-TX over Cat-3 telephone cable is to only
>> run one Ethernet link in one cable. This way cross talk between pairs is
>> minimized.

> To run one cable per one Ethernet link is not a trick but a norm. Except
> that the cable should be CAT5 and higher.

Cat-3 rated cable with a 100 pairs should be able to carry 10Base-T on every
pair, that is a total of 1 Gbps! Cat-5 cable with more more than 4 pairs has
been missing from the market, it has only recently become available. The way
I understand it is that Cat-5 rated cable should be able to carry 100Base-TX
on every pair.


(Follow-ups to news:comp.dcom.cabling.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Re: Shared Internet access in Finnish housing cooperatives


Petri Krohn wrote:

>
>> Aluminum burns like crazy, even in alloys. Especially installed
>> vertically in risers, where convection makes a great job of bringing
>> fresh oxygen into the burning area. Besides, it is more expensive than
>> almost any other material used for a conduit. I don't think aluminum
>> alloy made a great choice for riser conduits.
>
> It seems that in Finland fire safety has never been a big issue as in the
> US. Most newer buildings are reinforced concrete, older brick and mortar.
> The few steel constructions are mostly from the 1990's.
>
>> At any rate, it looks like you guys threw a dozen of well-established
>> industry standards out the window and attempted to establish your own.
>> Did you give your fire safety authorities a change to take a look at your
>> cabling? I'm especially concerned about those aluminum riser conduits.
>
> Using aluminum risers is not our way of doing things, it is the standard
> practice used by everyone else.
>
>>> Finnish telephone cable has proven its ability to carry
>>> 100Base-TX Ethernet for over a hundred meters.
>
>> It's a shame such great telephone cable is not available in other parts
>> of the world!
>
> I don't really think telephone cable is that much different in different
> parts of the world. All decent cable has twists. The lesson is that you do
> not really know how good the cable is until you have tried it in practice.

US Telephone cable will also do this, sort of.  Hell, barbed wire will carry
gigabit, as has been demonstrated.  The question is how much packet loss
you suffer in the process.

And it seems a fairly common practice to use CAT5 or better for telephone
installation in the US.

>>> The trick in running 100Base-TX over Cat-3 telephone cable is to only
>>> run one Ethernet link in one cable. This way cross talk between pairs is
>>> minimized.
>
>> To run one cable per one Ethernet link is not a trick but a norm. Except
>> that the cable should be CAT5 and higher.
>
> Cat-3 rated cable with a 100 pairs should be able to carry 10Base-T on
> every pair, that is a total of 1 Gbps!

It takes two pairs to carry 10-base-T.

> Cat-5 cable with more more than 4
> pairs has been missing from the market, it has only recently become
> available. The way I understand it is that Cat-5 rated cable should be
> able to carry 100Base-TX on every pair.

It takes two pairs to carry 100Base-TX.
>
>
> (Follow-ups to news:comp.dcom.cabling.)
>

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)


Re: Shared Internet access in Finnish housing cooperatives



>> Cat-3 rated cable with a 100 pairs should be able to carry 10Base-T on
>> every pair, that is a total of 1 Gbps!

> It takes two pairs to carry 10-base-T.

Two pairs in full-duplex mode carry a total of 20 Mbps.
If you want to carry 1 Gbps one way on a 100 pair cable you of cause
need a second 100 pair cable for the other direction.

Anyway, the issue here was not how to set up a Ethernet-connection, but the
limits of the signal carrying capacity of Cat-3 or Cat-5 cable. Using all
the pairs to carry the signal in the same direction is, I believe, more
difficult than to have half the pairs carry signal the other way. There
should be more cross-talk between the pairs. Still, if the cable is rated,
then it should be able cope with it.

>> The way I understand it is that Cat-5 rated cable should be able to carry
>> 100Base-TX on every pair.

> It takes two pairs to carry 100Base-TX.

Yes, but a normal Cat-5 cable has four pairs. The question is if you can use
all four pairs to carry 100Base-TX Ethernet, giving you two 100 Mbps
full-duplex links.


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Re: Shared Internet access in Finnish housing cooperatives


Dmitri(Cabling-Design.com wrote:

> Aluminum burns like crazy, even in alloys. Especially installed vertically
> in risers, where convection makes a great job of bringing fresh oxygen
> into the burning area. Besides, it is more expensive than almost any other
> material used for a conduit. I don't think aluminum alloy made a great
> choice for riser conduits.

It's not so great for destroyers either, as the British found out with HMS
Sheffield.




Shared Internet access in Finnish housing cooperatives


[Part 4: Wireless networking]

Free wireless access

One of the ultimate goals of this co-operative networking activity is to
cover neighborhoods with a "cloud" of free wireless Internet access.

Wireless WLAN networks should not be seen as a primary means of net access,
but as an alternative and additional form of access, more like the ultimate
icing on the cake.

Giving out free bandwidth requires a fixed backbone with bandwidth to spare.
Also the networks need to be based on a culture of sharing.

In the Helsinki wireless "model" open wireless access will be provided by
housing cooperatives. Access points are placed in elevator machine rooms
with strong sectoral antennas placed on the roofs. In concrete buildings it
is difficult to cover the apartments from with in the building but a
directional antenna can easily reach neighboring apartments through windows.

Full coverage requires thus cooperation between neighbors. In an reciprocal
agreement neighbors can grant each other access to their networks. The
practical solution goes even further. A central registry of co-op residents
is maintained in a Radius server (radius.helsinkiopen.net). All housing
cooperatives share this database for access control. The added value is the
ability to freely roam inside and between neighborhoods. Roaming agreements
between other networks will further expand the area of movement.

Giving free and uncontrolled access to everybody might seen like an even
better idea. This is a much more difficult concept to sell to co-op
management boards. The chief concern is not bandwidth usage but security.
Network operators want to be able control who uses their network and to keep
out spammers and an abusers.

To gain access it is thus not necessary to be a member of an organization
giving reciprocal service. It may be sufficient to be a member of an
organization who will authenticate you. In the Oulu public access wireless
network everyone who is a customer of the public library can gain access to
the free network.
http://www.panoulu.net /

The technical implementation of  access control can also be done with the
m0n0wall firewall. M0n0wall has a built in captive portal that connects to
an external Radius server.


VoIP roaming with DECT handsets

(This an idea for future developement.)

It would be highly useful if VoIP based telephony service could be provided
to roaming wireless users. The radio access network should be free of any
charge for all authenticated users. (The users would of cause pay their VoIP
gateway operator for any calls they make to fixed phone lines.

WLAN based VoIP handsets have been expected on the market for several years
now. It now seems that WLAN may not be the right technology for mobile VoIP
services after all. A far maturer technology is DECT (Digital Enhanced
Cordless Telecommunications). These cordless phone products have been on the
market for over 10 years with cheapest handset + base station sets available
for under 30 euros.
http://www.dect.ch/pdf/TechnicalDocument.PDF

The DECT Radio or "air" interface provides roaming capabilities similar to
the GSM network. DECT roaming is in fact limited by the tie up of DECT
handsets to individual base stations.

For true roaming to be enabled the base stations need a complete redesigned.

  1. POTS connectivity replaced by Ethernet/IP-connectivity.
  2. Authentication of handset moved to central
     authentication server or Radius server.
  3. DECT roaming mapped to some IP-based
     roaming scheme, possible mobile IP.

The North American counterpart of DECT, "Personal Wireless
Telecommunications" or PWT newer got of the ground. Instead a DSS based
system operating at 2.4GHz has gained popularity.

Building combined 2.4GHz WLAN + cordless phone base station might be easier
in the US as one antenna might be used to serve both networks. However, the
price of  2.4GHz handsets far exceeds the price of DECT handsets. 2.4GHz
cordless handsets may not be competitive against true WLAN + VoIP handsets.


(Follow-ups to news:alt.internet.wireless.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 2: Router issues]

Bandwidth-sharing problems

Early HomePNA networks suffered from bandwidth-sharing problems.
In an shared Internet connection bandwidth usage between different users
may differ by over one thousand fold. The heaviest traffic is caused by file
sharing and other p2p-programs.

Without any bandwidth limitations or priorization two or even one BitTorrent
user can disable a network and block net access to all neighbors. In an
asymmetric ADSL-connection saturation of the uplink will cause the free
capacity of the downlink to become unusable. Network latency (ping) grows
to over 1 second, practically freezing all other traffic.

ISP:s and housing cooperatives took very different approaches to solving the
problem:

In ISP-run networks the built in bandwidth limitation features of HomePNA
switches were taken into use. Per user bandwidth was throttled down to a
minuscule 128 or 256 kbps.

Cooperative networks wanted to provide each user the full capacity of the
network. Artificial restrictions were disliked. The solution was user
education. Network activists would monitor network traffic, advise neighbors
on proper usage of p2p-software and even temporarily disconnect users who
failed to follow the guidance.

Technical solutions

Luckily purely technical solutions have become available to the bandwidth
sharing problem in the form of traffic shapers. One useful alternative is
the FreeBSD-based firewall distribution m0n0wall with an easily configurable
traffic shaper:
http://www.m0n0.ch/wall /

A Finnish company, Staselog also produces a traffic shaper for cooperative
in-house networks:
http://www.staselog.fi/en/products/index.html

Functions of a traffic shaper:
  1.Delay outgoing traffic so the uplink is newer saturated.
  2.Prioritize interactive traffic.
  3.Recognize p2p-traffic and set to lowest priority.
  4.Give each user an equal share of the usable bandwidth.


Routing with one public IP address

A shared Internet connection will typically use only one public IPv4
address. A router has to perform Network Address Port Translation (NAPT)
between the internal network and the Internet. Normally NAPT blocks all
users from running servers on their PC:s. This is a problem for p2p
applications and may block VoIP services altogether.

A solution is to open a fixed set of port mappings in the router. A set of
ports is allocated for each apartment. Also a set of fixed private addresses
is allocated for each apartment.

Normal users use DHCP to get their IP addresses in the private network. If a
user wants to run a server or a p2p program in active mode, he configures
his PC to use his fixed private address. The set of open ports will be
mapped to this address.

Example:
 - address 10.10.10.157 is reserved for apartment 157
 - ports 51570 - 51579 are mapped to address 10.10.10.157 in the
   private network.

A general configuration of the router can be made that can serve any shared
residential network.  When using m0m0wall this configuration takes the form
of an XML file that can easily be distributed. (Hope to make this available
after some more editing :-)


(Follow-ups to news:alt.comp.networking.connectivity.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


This is part one of a longer post on co-operative network activity in
Finland. The Finnish model differs from the way Internet services are
provided in most other counties. Information on Finnish co-ops has never
before been available in English. Here I have tried to put together all the
relevant information and experience.

  1 Networking in housing co-ops - HomePNA?
  2 Router issues
  3 Cabling issues - Ethernet on phone wires
  4 Wireless networking

This message has been cross-posted to several newsgroups. General follow-ups
to news:comp.networking.connectivity.

[I am sorry for the repost. My ISP's news server crashed and failed to
deliver anything. Cancels have been issued on the originals.]

*** *** ***

The beginning - Operator-driven networks

The first Finnish in-house networks were built in the late 1990's when
construction companies began installing structural cabling in new apartment
buildings. An Ethernet LAN was used to provide Internet access to residents.

This brought external service providers in to the in-house network. In this
business model the operator (telco) would sell the the service directly to
to the resident.

Sometimes the building would be connected to the service providers network
by fiber-optic cable. The fiber would be placed at an early stage of
construction. The newly formed housing cooperative would pay the full cost
of the cabling work as sign-up fees for the Internet service. The agreement
between the co-op and ISP would not allow the co-op to buy Internet service.
Instead it allowed the ISP to take over the internal wiring and monopolize
the network. The service provider was free to price the service as they
pleased. The co-op could not abandon the agreement as it meant loosing their
large sign-up fees.

This model did bring residents fast Internet access. It did not however
bring down the cost of access as the service was always priced at or above
the price of slower fixed access alternatives. The monthly fee for fast
Ethernet access in these houses is around EUR 50 with little change in
sight.

HomePNA

A new technology, HomePNA was introduced to in-house networks by
the Internet operator Jippii (now Saunalahti). Originally Home Phoneline
Networking (HomePNA) was marketed in the US as a way of building
home networks by utilizing the multiple existing phone sockets in the house.
In Asia the technology was adapted for ISP use with the introduction
HomePNA 1.1 switches.
http://www.homepna.org/products/#mdu

In an in-house HomePNA network a stack of HomePNA switches is placed in
the central telephone wiring closet of the building. Each apartment is
connected to one port on the switch using the same twisted pair that carries
telephone traffic to the apartment.

Internet connectivity is provided by one (or more) ADSL or G.SHDSL
connections.

Operator-run HomePNA networks reached their peak popularity by the end of
2003. In that year most landlords owning apartment blocks, including
"council housing", made agreements with ISPs to market HomePNA services to
tenants at a price of around EUR 35 a month.

The last year has seen a steady decline in popularity of ISP run HomePNA
networks.

 1. A sharp decline in ADSL prices and increase in speeds has made HomePNA
    service uncompetitive against ADSL and cable modem connections starting
    at EUR 19,50 a month.

 2. The business model is unworkable. An infrastructure like an in-house
    network needs "monopoly protection", not market competition. In the
    worst case, one housing cooperative might have two competing HomePNA
    networks installed in the same wiring closet, both networks providing
    service to 2 - 3 customers.

Also one problem is that often the operator providing HomePNA service is
also providing ADSL service in the same area. These operators are unwilling
to push HomePNA prices below ADSL prices.


Cooperative networks

In 2000 housing cooperatives in Finland started building their own HomePNA
networks. In this model the housing cooperative would own the networking
hardware and pay for the Internet connection.

In early networks only those residents interested in the fixed Internet
connection would take part in the costs. A subscription fee was set up and
collected monthly by the housing cooperative, along  with the maintenance
fee and any other extras for services like the weekly sauna or parking
space. The cost of hardware and installation was covered by the fee in about
two years.

In these early networks about 50% of residents were connected with monthly
fees at around EUR 7.

Some of the first networks were set up in the Helsinki neighborhood of
Maunula in an government initiated project:
http://www.sitra.fi/eng/index.asp?DirID=68&DocID=4248

Internet access to everyone

Newer networks have adopted a different model. All apartments are connected
to the network and Internet service is provided without any extra fee. At a
minimum Internet-service can be provided at around EUR 1 per month with
around EUR 100 per apartment in initial investment costs.

Not having to connect and disconnect individual apartments greatly eases the
maintenance of the network.

In houses with free Internet access network usage has reached a level of 85%
of apartments.


The future of HomePNA

With "Full Rate" ADSL connections at 8/1 Mbps becoming available to
consumers at a price of EUR 45 and to housing cooperatives at EUR 115  the
limited speed (1 Mbps) of HomePNA 1.1 has become a bottleneck.
To lock the key "heavy users" to the cooperative network faster speeds must
be available. Construction of new HomePNA-based networks now seems to have
come to a standstill.

HomePNA 2.0 at 10Mbps proved to be too prone to cross talk so no switches
are available. HomePNA 3.0 could provide a speed of 100Mbps but the switches
have yet to reach European markets.

At the same time the price of compact ADSL DSLAMs (switches) has dropped to
almost the same level as HomePNA switches, at around EUR 50 per subscriber.
The problem with ADSL is its ATM foundation, which causes unnecessary
configuration issues in an otherwise purely Ethernet-based network. VDSL
would provide better Ethernet compatibility and higher speeds, but the
standards are immature and hardware is incompatible.

Ethernet would provide the best alternative, but usually the wiring is
missing. Finnish housing cooperatives are now facing a tough technical
choice between rewiring for Ethernet and adapting ADSL or VDSL technology
for in-house networks.


Finnish national policy

The Finnish national "Broadband Strategy" emphasizes competition to the
detriment of  infrastructure. The aim is to utilize the existing coper base
of the telephone network to its fullest. In this model each user will have
an individual subscription with a profit driven telco.

Virtually no encouragement is given to cooperative networks or even in-house
networks.
http://www.laajakaistainfo.fi/english/index.php

The opposition, the "fiber party" is largely concentrated in the
Swedish-speaking districts of Ostrobotnia. These people believe in
the importance of infrastructure; fiber-optic Ethernet to every house!
http://www.seutuverkot.net (in Finnish)


Housing in Finland

Most Finns live in apartment blocks. Finland has the second highest
percentage of  apartments in Europe after Spain. Also, a large proportion of
Finns own their apartments. Most apartment houses are organized as housing
cooperatives. The first housing cooperatives were built in Finland around
1900.

     Some of the first Finnish Housing cooperatives are located in the
     Katajanokka neighborhood in Helsinki:
      - http://www.photofora.com/eugene/Jan2003/helsingfors03/index_18.htm
      - http://www.codeman.fi/photo/katajanokka.jpg

Finnish writers often translate the Finnish word "asunto-osakeyhtiö" as
"housing company". The term "housing cooperative" is more accurate as the
form of incorporation of Finnish cooperatives is identical with those in the
US.  In fact, the housing cooperative model was brought to the United States
by Finnish immigrants.

     "The first true cooperative development in the United States was
      started in 1918 by a group of Finnish artisans-the Finnish Home
      Building Association in Brooklyn, New York. "
       - http://www.coophousing.org/HistoryofCo-ops.pdf
       - http://www.findarticles.com/p/articles/mi_m0254/is_4_59/ai_68704399


*** ***
Vocabulary

Housing cooperative
  "Housing cooperatives are a form of homeownership where individuals own
   shares or memberships in a corporation that owns or controls the land and
   buildings that provide housing. The ownership of a share entitles one to
   occupy a unit within the cooperative."
   http://www.coophousing.org/glossary.shtml

Council housing
   (British term) Social housing owned by the city or municipality.

MDU
   Multi-Dwelling Unit

In-house network
   A LAN connecting apartments in an apartment block and providing Internet
   access

Internet connection sharing
   In English parlance "connection sharing" is often used to refer to
   sharing your Internet connection between multiple computers. In this
   text it refers to sharing one WAN connection and possibly one IPv4
   address between multiple subscribers.

Operator
   In the US often referred to as "carrier". A large telco offering
   telephone and ISP services.

Euro (EUR)
   The European Currency Unit, now rated at about US $1.32 to one Euro.


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 2: Router issues]

Bandwidth-sharing problems

Early HomePNA networks suffered from bandwidth-sharing problems.
In an shared Internet connection bandwidth usage between different users
may differ by over one thousand fold. The heaviest traffic is caused by file
sharing and other p2p-programs.

Without any bandwidth limitations or priorization two or even one BitTorrent
user can disable a network and block net access to all neighbors. In an
asymmetric ADSL-connection saturation of the uplink will cause the free
capacity of the downlink to become unusable. Network latency (ping) grows
to over 1 second, practically freezing all other traffic.

ISP:s and housing cooperatives took very different approaches to solving the
problem:

In ISP-run networks the built in bandwidth limitation features of HomePNA
switches were taken into use. Per user bandwidth was throttled down to a
minuscule 128 or 256 kbps.

Cooperative networks wanted to provide each user the full capacity of the
network. Artificial restrictions were disliked. The solution was user
education. Network activists would monitor network traffic, advise neighbors
on proper usage of p2p-software and even temporarily disconnect users who
failed to follow the guidance.

Technical solutions

Luckily purely technical solutions have become available to the bandwidth
sharing problem in the form of traffic shapers. One useful alternative is
the FreeBSD-based firewall distribution m0n0wall with an easily configurable
traffic shaper:
http://www.m0n0.ch/wall /

A Finnish company, Staselog also produces a traffic shaper for cooperative
in-house networks:
http://www.staselog.fi/en/products/index.html

Functions of a traffic shaper:
  1.Delay outgoing traffic so the uplink is newer saturated.
  2.Prioritize interactive traffic.
  3.Recognize p2p-traffic and set to lowest priority.
  4.Give each user an equal share of the usable bandwidth.


Routing with one public IP address

A shared Internet connection will typically use only one public IPv4
address. A router has to perform Network Address Port Translation (NAPT)
between the internal network and the Internet. Normally NAPT blocks all
users from running servers on their PC:s. This is a problem for p2p
applications and may block VoIP services altogether.

A solution is to open a fixed set of port mappings in the router. A set of
ports is allocated for each apartment. Also a set of fixed private addresses
is allocated for each apartment.

Normal users use DHCP to get their IP addresses in the private network. If a
user wants to run a server or a p2p program in active mode, he configures
his PC to use his fixed private address. The set of open ports will be
mapped to this address.

Example:
 - address 10.10.10.157 is reserved for apartment 157
 - ports 51570 - 51579 are mapped to address 10.10.10.157 in the
   private network.

A general configuration of the router can be made that can serve any shared
residential network.  When using m0m0wall this configuration takes the form
of an XML file that can easily be distributed. (Hope to make this available
after some more editing :-)


Security

Security in an in-house network requires that users cannot communicate
directly through the LAN using local IP-addresses or LAN-protocols.
All traffic must pass through a router and be based on public IP-addresses.
The technique to achieve this is to use "port isolation" in the Ethernet and
HomePNA switches. This feature is available in all switches targeted for
the MDU-market.

In-house networks usually share one public IP-address among all users. The
NAPT router isolates  the house network from the Internet and provides a
built in firewall.


(Follow-ups to news:alt.comp.networking.connectivity.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 3 Cabling issues - Ethernet on phone wires]

"Helsingin Alueverkkoyhdistys" (Helsinki Neighborhood Networking
Association) is a group of local volunteers and activists with the
altruistic aim of providing "free"¹  Internet access to everyone.

The ultimate goal is to build community owned fiber-optic networks in
residential neighborhoods. Equally important is an open network of wireless
access points. We believe that universal free and open WLAN access is only
possible, if its backed up by an solid infrastructure of shared wired
networks.

The first stage is to build in-house networks in the apartment blocks and
housing cooperatives. Only when we reach a critical mass of  in-house
networks can we start connecting them into neighborhood networks. Housing
cooperatives are important also in the sense that they can easily be
persuaded to give away the free bandwidth needed for the open wireless
coverage.

    ¹ Free in this case means free as in "free lunch"; there is no such
      thing. Someone will have to pay for the service, or better yet
      build the infrastructure that provides the service. The idea is to
      make Internet access a basic infrastructure like streets, electric
      lighting and running water, available to everyone in need of it.
      This infrastructure should be provided by the same people who
      provide these basic services, in most cases the property owners.


Activity has been greatest in two new Helsinki neighborhoods, Ruoholahti and
Pikku-Huopalahti. These neighborhoods consist of  prefabricated concrete
apartment blocks built mainly in the early 1990's with anywhere between 30
and 170 apartments each.
 - http://www.kaupunginosat.net/ruoholahti/kuvagalleria/kuvagalleria.htm
 - http://www.saunalahti.fi/asyhd/kuvplahti/1/kuvat.html


Ethernet everywhere!

From the start the aim has been for higher speeds, thus the focus on
Ethernet technology.

It was felt that if the slow but popular HomePNA technology would be used
for in-house networks, it be a serious hindrance to fiber-optic neighborhood
networks. The limited bandwidth that can be delivered by HomePNA can always
be served by ADSL or other technologies over coper.

Also the focus has been on finding cheap or "zero-cost" solutions for
Ethernet. Housing cooperatives may be willing to invest more heavily, but in
Helsinki all new neighborhoods are mixed neighborhoods with both
resident-owned co-ops and city-owned social housing. The technical solutions
should be so cheap that they can be adopted by council houses with very
limited budgets.

Add-on cabling

The standard way of rewiring houses in Finland has been to use diamond
drills to pierce floors and walls. Heavy-duty aluminum profile conduits are
installed in stairwells to house new cabling. In apartment buildings this
effort was only taken up in conjunction with other renovations, like
renewing the electrical wiring.

Rewiring for the sake of Internet access had not taken up. The only
residential buildings where the effort was made where student dormitories.
The costs would be around 400 euros per apartment. We started looking for
cheaper, lighter alternatives.

Telephone and central antenna cables to apartments are typically enclosed in
20 mm plastic tubing. This would leave space for an other cable in the same
conduit. Also, there should be no need to remove existing telephone wire to
provide the additional Ethernet access.

Initially there was a great distrust that new wire could be pulled alongside
in the same conduit. The only reference was an undocumented 1995 effort to
rewire the dormitories of the Helsinki University of Technology with Cat-5
cable. This was done by student volunteers.

The first houses were rewired in 2003 by volunteer residents. When it was
established that the technique can be utilized, this approach was also taken
up by a large wiring contractor. Several houses with hundreds of apartments
have been wired with a 100% success rate.

Inside the apartment the Finnish legacy telephone socket in one room  is
replaced with a new faceplate with RJ11 and RJ45 connectors. The cost
estimate for  this type of "add-on" wiring is about ? 150 per apartment.
Success requires that the original construction is up to standard.

Horizontal access

Horizontal telephone cabling in Finnish houses is often done with direct
burial cable. There is no horizontal conduit connecting the splices in
different stairwells. Even worse, a housing cooperative might consist of
several detached buildings separated by an asphalt covered courtyard.

In a prototype house fiber-optic cable was used to connect the
Ethernet-switches in the different buildings. Volunteer residents dug up a
ditch for the underground conduit connecting the buildings. Later experience
has shown this effort to be unnecessary; Finnish telephone cable has proven
its ability to carry 100Base-TX Ethernet for over a hundred meters.

The structure for the in-house Ethernet network in a large apartment block:

   1. Place one 24-port Ethernet switch near each stairwell, preferably
      in the electricity or central antenna closet. Usually the Scotchlok
      splice for the telephone wiring is located in this same space.
   2. Pull new Cat-5e cables from the closet to each apartment.
   3. Use free pairs in the direct burial telephone cable to connect the
      Ethernet switch to the central telephone wiring closet at 100 Mbps.
   4. Place the router and central switch at the telephone wiring closet.

Using Cat-3 telephone cable

New Finnish houses built after the year 2000 usually have structural
cabling, that is separate Cat-5e cables for Ethernet and telephone with
RJ-45 connectors. Older houses houses only have cabling for telephone.
Although it is not widely publicized, Finnish telephone cable from the
1990's has a Cat-3 rating.

Houses built after 1995 usually have three twisted pairs serving each
apartment. It has turned out to be quite a simple task to convert the
cabling to Ethernet use. Originally Finnish legacy telephone sockets are
installed with only one pair connected. This leaves two pairs free for use
by Ethernet. The transformation consists of exchanging one legacy socket for
a RJ-11 / RJ-45 combination faceplate and resplicing the Ethernet-pairs so
that only one socket is connected.

The biggest problem for high speed traffic is the Scotchlok splices used to
connect different parts of the telephone cabling. These are not made to
Cat-3 standards. Practical tests however have shown the connections not to
be a problem. Most installations have worked flawlessly even at higher
speeds of 100 Mbps.

Distances over 100 meters do not seem to pose a problem either. Zero error
operation has been observed in telephone cable at
 - 100 Mbps for over 100 meters
 - 10 Mbps for over 150 meters

The trick in running 100Base-TX over Cat-3 telephone cable is to only run
one Ethernet link in one cable. This way cross talk between pairs is
minimized.

Giving up fixed-line telephone

Houses built before 1994 usually only have two pairs, in the form of a
twisted star quad, serving each apartment. Using these pairs for Ethernet
traffic poses two problems:

1. Star quad has an impedance of 120 ohms, which differs from the twisted
   pair impedance of 100 ohms.
2. Using both pairs for Ethernet means that the resident would have to give
   up fixed line telephone service.

In practical tests the impedance mismatch between the pull to the apartment
and the multi-paired trunk cable has shown not to be a problem. 10Base-T
works reliably.

Giving up the fixed phone may not be a problem. Most voice has already "gone
mobile" i.e. moved to mobile phones. The remaining fixed voice traffic is
fast moving to VoIP over the Internet. New programs like Skype and VoIP
gateway service to consumers has made this move possible.

In a survey of residents in a potential conversion site 83% of residents
wanted fixed Internet access. Only 45% required fixed telephone service.
This means that over half of the apartments could be converted to Ethernet
with about 30% needing ADSL or VDSL service.

Filtered solutions for POTS + Ethernet

It may also be possible to run POTS and Ethernet simultaneously on the same
two twisted pairs. Ethernet would occupy the higher frequency band over POTS
on the same pair. Splitters or filters would be used in each end to separate
the two types of traffic.

A company in the US, Energy Transformation Systems, makes filters for this
purpose.
http://www.etslan.com/ethernet.php

A Finnish company H.Vesala Ltd. also makes a similar filter, although for
ADSL use.
http://www.vesala.fi/english/products/adsl_splitters.html

A slightly different implementation is provided by etherSPLIT.
http://www.ethersplit.com /


(Follow-ups to news:comp.dcom.cabling and news:comp.dcom.lans.ethernet.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Shared Internet access in Finnish housing cooperatives


[Part 4: Wireless networking]

Free wireless access

One of the ultimate goals of this co-operative networking activity is to
cover neighborhoods with a "cloud" of free wireless Internet access.

Wireless WLAN networks should not be seen as a primary means of net access,
but as an alternative and additional form of access, more like the ultimate
icing on the cake.

Giving out free bandwidth requires a fixed backbone with bandwidth to spare.
Also the networks need to be based on a culture of sharing.

In the Helsinki wireless "model" open wireless access will be provided by
housing cooperatives. Access points are placed in elevator machine rooms
with strong sectoral antennas placed on the roofs. In concrete buildings it
is difficult to cover the apartments from with in the building but a
directional antenna can easily reach neighboring apartments through windows.

Full coverage requires thus cooperation between neighbors. In an reciprocal
agreement neighbors can grant each other access to their networks. The
practical solution goes even further. A central registry of co-op residents
is maintained in a Radius server (radius.helsinkiopen.net). All housing
cooperatives share this database for access control. The added value is the
ability to freely roam inside and between neighborhoods. Roaming agreements
between other networks will further expand the area of movement.

Giving free and uncontrolled access to everybody might seen like an even
better idea. This is a much more difficult concept to sell to co-op
management boards. The chief concern is not bandwidth usage but security.
Network operators want to be able control who uses their network and to keep
out spammers and an abusers.

To gain access it is thus not necessary to be a member of an organization
giving reciprocal service. It may be sufficient to be a member of an
organization who will authenticate you. In the Oulu public access wireless
network everyone who is a customer of the public library can gain access to
the free network.
http://www.panoulu.net /

The technical implementation of  access control can also be done with the
m0n0wall firewall. M0n0wall has a built in captive portal that connects to
an external Radius server.


VoIP roaming with DECT handsets

(This an idea for future development.)

It would be highly useful if VoIP based telephony service could be provided
to roaming wireless users. The radio access network should be free of any
charge for all authenticated users. (The users would of cause pay their VoIP
gateway operator for any calls they make to fixed phone lines.

WLAN based VoIP handsets have been expected on the market for several years
now. It now seems that WLAN may not be the right technology for mobile VoIP
services after all. A far maturer technology is DECT (Digital Enhanced
Cordless Telecommunications). These cordless phone products have been on the
market for over 10 years with cheapest handset + base station sets available
for under 30 euros.
http://www.dect.ch/pdf/TechnicalDocument.PDF

The DECT Radio or "air" interface provides roaming capabilities similar to
the GSM network. DECT roaming is in fact limited by the tie up of DECT
handsets to individual base stations.

For true roaming to be enabled the base stations need a complete redesigned.

  1. POTS connectivity replaced by Ethernet/IP-connectivity.
  2. Authentication of handset moved to central
     authentication server or Radius server.
  3. DECT roaming mapped to some IP-based
     roaming scheme, possible mobile IP.

The North American counterpart of DECT, "Personal Wireless
Telecommunications" or PWT newer got of the ground. Instead a DSS based
system operating at 2.4GHz has gained popularity.

Building combined 2.4GHz WLAN + cordless phone base station might be easier
in the US as one antenna might be used to serve both networks. However, the
price of  2.4GHz handsets far exceeds the price of DECT handsets. 2.4GHz
cordless handsets may not be competitive against true WLAN + VoIP handsets.


(Follow-ups to news:alt.internet.wireless.)

--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




Re: Shared Internet access in Finnish housing cooperatives



> Your parts and/or numbering are either out of order or duplicate
> numbered.

My ISPs news server crashed while I was sending the batch. Panicked and
resent after six hours. If you are seeing duplicates, it is because your
news server does not recognize cancel messages.

Anyway, I put the whole story in the web. You can see all parts in the right
order :-)
http://www.helsinkiopen.net/shared_internet_access.html


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen  --  http://www.helsinkiopen.net




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