I'm looking at options for networking our complex which has 207 houses.
DSLAM - Fibre would be great, but a switch to support 207 fibre connections would cost plenty! CAT5 has a ~100m limit.
Our complex is a 400m square.
You would specifically not use fiber for your setup. Fiber is for high capacity point to point links. Get a Zyxel VDSL2+ DSLAM range is 600m to 1,5km. Contac
Communiverse (021 555 1024) - Werner, and if he can't help you get hold of Zyxel USA.
See
http://scratchpad.wikia.com/wiki/DsLam
=== DSLAM forms a large area LAN ===
A Dslam connects via [[TwistedPair]] copper wire to a VDSL modem upto a distance of 600m. The wireing for a DSLAM are laid via [[TelephoneNetworkRollout]] which should be seen as a wider attempt to implement legal [[MeshNetworking]], [[FreeSpaceOptics]] and illegal [[WiMax]]. A DSLAM is one of the most powerful network and communications devices on a cost performance basis. That is why Telco's use it. The drawback is the need for cabling. Where possible [[FreeSpaceOptics]] should be used. Fiber and/or DSLAM are used to interlink these FSO nodes depending on multiple factors such as desired bandwidth, user density and future scalability of the network.
=== Features ===
* DSLAM: Digital Subscriber line access multiplexer
* Is a Point-to-Multipoint device or Router and Switch combination.
* It has multiple ATM ports functioning as a SwiTch on the front of the DSLAM box and one Ethernet upload port at the back from where configuration of the DSLAM is done.
* Each ATM DSLAM port interfaces with a single VDSL modem via the ATM protocol using AWG24 [[TwistedPair]].
* A VDSL modem is an '''ATM-to-Ethernet''' protocol converter.
* Each VDSL modem provides upto 32 MAC addresses to an Ethernet device.
* The VDSL modem hands out an Ethernet [[DhCp]] lease to an Ethernet device.
* Zyxel DSLAM Sizes vary between sixteen and 200 ports.
* Zyxel VDSL2+ is the preferred DSLAM solution.
* The eight port uses eight RJ-11 telephone jack connectors.
* The larger port sizes use a Telco-50 connector cable.
* It has QOS, bandwidth increments of 32k, P2P blocking and other bandwidth management features.
* Downstream bandwidth 24meg(ADSL2+), 24meg(VDSL), 50meg(VDSL2)
* Upstream bandwidth 1.6meg(VDSL2+), 10meg(VDSL), 50meg(VDSL2)
* Downstream distances ~626m(VDSL2+), 1km(VDSL), 1.5km(VDSL2+)
* A VDSL modem needs two AWG24 wires, Ethernet needs eight wires.
* Allows for triple play services such as voice,video and data.
*
http://en.wikipedia.org/wiki/Triple_play_(telecommunications)
* Holiday Inn uses a DSLAM to ''stream video on demand'' to their hotel rooms in South Africa.
=== Multicasting function of DSLAM ===
*
http://en.wikipedia.org/wiki/Multicast
*
http://en.wikipedia.org/wiki/IP_Multicast
http://tech.slashdot.org/tech/08/07/18/2040213.shtml explains how ISPs have disabled the "multi-cast" video streaming
function on their DSLAM routers. Bit-torrents from [[TelevisionOverInternet]] overcomes this obstacle by stream the content over port 80 of HTTP. DSLAMs were designed with multi-casting video streams in mind so that there is no need for torrents on a local DSLAM network.
=== Role of the DSLAM ===
DSLAM: '''Digital subscriber line access multiplexer'''
A DSLAM is a viable alternative to many Fiber deployments, it allows people to build their own private telephone exchanges via [[TelephoneNetworkRollout]] and underground cabling in the exact same manner that a Telco builds their exchanges. The word ''subscriber'' confuses the role of a DSLAM. Human beings subscribe to a certain world view. An ATM DSLAM and an Ethernet [[SwiTch]] are not subscribing to anything, they are interfacing via a communications protocol: Either ATM or Ethernet to another device using the same protocol.
On top of the ATM protocol the IP protocol is implemented. IP is also implemented over Ethernet protocol so that as far as the users are concerned they are using IP from the CPE Ethernet port to the DSLAM Ethernet upload port and need not concern themselves with the VDSL modem implementing IP over Ethernet and then over ATM.
A DSLAM functioning as a SwiTch and RouTer, receives the VDSL modem data on an ATM port, converts it to Ethernet and streams this data via the single Ethernet gigabit link that physically plugs into the DSLAM itself unto an Ethernet based network. This Ethernet network is usually a Telco network but for communities setting up their own telephone exchange it will be their own server streaming whatever can be streamed over Ethernet using a whatever protocol such as IP.
The data uploaded to the DSLAM via it's Gigabit Ethernet port is converted to the ATM protocol and streamed out to each VDSL modem from each respective ATM port on the DSLAM. Each VDSL modem converts the ATM protocol data to Ethernet data. As far as the end user is concerned he is using the IP protocol from end-to-end. The DSLAM overcomes the distance limitation of 100m over copper wire that limits Ethernet usage. The ATM protocol uses fixed packet widths and Ethernet uses variable data rates. As the distance of a wire increases, its resistance increases hence the the need for the ATM protocol between the ATM DSLAM port and the VDSL modem. For [[FiberOptics]] the preferd protocol is Ethernet due to its simplicity. ATM is a complex protocol but has to be used for long distance communication over copper exceeding 100m.
Up to eight DSLAMs can be daisy chained. Dslam1 connects via one of it's ATM ports to Dslams2's ATM port. These two Dslams then communicate via the ATM protocol. View a DSLAM as forming a huge LAN. These large DSLAM LANs link into a WAN and view a Telephone company as a WAN operator. These WANs are linked via fiberoptics using the Ethernet protocol. A Dslam just like a Router, Hub, Bridge and Switch per se has got nothing to do with a Telephone company. All Telcos just happen to use Ethernet based RouTers, SwiTch and the ATM based switch/router combination known as a DSLAM. A community setting up their own telephone exchange via a DSLAM is just setting up a large area LAN that can radiate out to 5km.
'''Digital subscriber line access multiplexer''' can also be rephrased as: ''VDSL modem router.'' [[BR]] A DSLAM should be visualized as a long distance switch connected to a Router. A [[RouTer]] connected to a [[SwiTch]] can also be described as ,,multiplexing,, the SwiTch data via it's Gigabit Ethernet port unto an Ethernet based network. As far as RouTers and DSLAMs are concerned their Gigabit Ethernet ports ''multiplexes'' the Ethernet protocol data unto a computer network which also uses the Ethernet protocol. The DSLAM converts the ethernet data that was uploaded to it by its physical gigabit Ethernet port, converts it to the ATM protocol and streams it via ATM to the ATM port of each respective VDSL modem. Telkom links from the CO to the CPE can also be formed using Ethernet based RouTers and SwiTches but because of the distance limitation of 100m over copper with Ethernet, telephone exchanges use a DSLAM.
Place an Ethernet switch in your study and call it the [[CentralOffice]]. Connect it to another switch in the kitchen and call it the CPE(Customer premise equipment). These two Ethernet switches communicate via the ethernet protocol, which has got nothing to do with "customers", "premises" or "offices". Place a DSLAM in your office and connect its Gigabit Ethernet port an Ethernet router connected to the Internet. Place a VDSL modem in the kitchen and lounge and run [[TwistedPair]] to each modem. Call the VDSL modem the CPE and call the DSLAM the CO. The DSLAM interfacing via ATM with the ATM port of the VDSL modem which in turn converts it to Ethernet has also got nothing to do with "customers" or "offices". It is just a telco naming convention. Now take the same DSLAM and run [[TwistedPair]] to a VDSL modem outside the home over multiple walls via [[TelephoneNetworkRollout]]. The telco jargon term for this is [[OutsidePlant]] connectivity or OSP. Between Telkoms DSLAM connection and the VDSL modem at the CPE there is Main_Distribution_Frames, [[CentralOffice]], Local loops and a [[ServingAreaInterface]], but as far as the DSLAM is concerned it still communicates via ATM with the ATM port of the VDSL or VDSL modem no matter through what [[ServingAreaInterface]], distribution frames or whatever loop you wish to take the [[TwistedPair]] through. The failure to distinguish this causes confusion when trying to understand the role of the DSLAM in and of itself which is independent of all these telco jargon terms.
=== Generations of DSLAMs ===
* ADSL 256k up and 4meg down.
* ADLS2 1meg up and 24meg down.
* VDSL 10meg up and 24meg down.
* VDSL2 50meg up and 50meg down.
=== VDSL2+ speeds and reach ===
* Price $900 for 16-port DSLAM
* Upload and Download: 50megs at 650m per DSLAM port.
As the distance of the VDSL modem from the DSLAM increases the throughput will drop. At any distance where the speed becomes unacceptable, connect a Fiber/Ethernet module to the VDSL modem's ethernet port. The Fiber/Ethernet module is essentially a two-port SwiTch.
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