DsLam

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Simulate DSLAM with Switch/Ethernet trasceiver
DSLAM functionality can be simulated by connecting an Ethernet extender from http://www.versatek.com/products/ethernet_extender.htm to a layer-2 or 3 switch.

Connect a layer-2 switch to a Lxt971Aphy transceiver which converts the three volt levels of the Ethernet physical layer to binary two as explained at FreeSpaceOptics. The two voltage levels is pulsed down a two wire system using OFDM modulation at -48 volts for an Ethernet over copper solution to a distance of 4km or 600m at increased bandwidth(100Meg) using DSP or FpGa. VDSL physical layer protocol will be used.

Due to the internal resistance of copper wire the signal will be attentuated at 600m. Physically on a scope the square voltage pulsed becomes rounded. A buffer/http://en.wikipedia.org/wiki/Schmidt_trigger spaced every 600m repeats the -48volts, forming any number of hops like a fiber switch. Fiber only allows on/off light pulses, by using OFDM DSP based modulation on copperm, fiber like on/off functionality is emulated, achieving the same type of unlimited repeater nodes.

Thus a 100Meg Ethernet signal can be extended for over 10km-100km over a single twisted pair copper using repeaters every 600meters. The eight wires used in Ethernet is according to the PHY layer specification, intended for use over short distances creating three voltage levels. But computers work on 0/1 or 0/5volt binary logic only.

Normal 100Meg copper based switches allows only four daisy chained connections because each switch has to convert from three level voltage at PHY layer to MAC and data layer which takes time measured as latency.

Lay cabling on the residential walls forming a mini-WAN between all the houses in a block. Split the cabling at multiple intervals so that only a section could be stolen and not the entire cable on a residential walls linked removed.

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. A DSLAM is a long-reach broadband over copper solution. DslamOem, DslamAcademic

Features
* Leon from Communiverse are a SA Zyxel DSLAM distributor - 082 572 4260 * DSLAM: Digital Subscriber line access multiplexer * Is a Point-to-Multipoint device or Router and Switch combination. * 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. * http://www.versatek.com/products/dslam-md3024.htm Veratek VDSL2 ITU-T G.993.2  VersaTek * Up to 200m at 100Mbps, Up to 1 Km at 40Mbps, Up to 2Km at 8Mbps * http://www.aktino.com/ and http://www.zyxel.com are the preferred brands. * http://www.aktino.com provides 100 Mbps over copper out to 12 Kft (3.7 Km) * 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_%28telecommunications%29 * Holiday Inn uses a DSLAM to stream video on demand to their hotel rooms in South Africa.
 * 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.

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.

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 1,5km.

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.

Zyxel is preferred brand
A DSLAM is just a long range switch. * VES-1616F-34 16-port DMT 5-band VDSL Switch DSLAM switch * P-871-1/P-871H Compatible CPE VDSL modem

DSLAM distributors in South Africa
* DslamDistributors * Leon from Communiverse are a SA Zyxel DSLAM distributor - 082 572 4260 * http://www.us.zyxel.com/landing_page/landing_page_final.php * http://us.zyxel.com/web/product_family_detail.php?PC1indexflag=20040520161421&CategoryGroupNo=PDCA2006058 * http://www.buy.com/prod/zyxel-ves-1616f-34-5-band-vdsl-switch-2-x-expansion-slot-2-x-16-x-vdsl/q/loc/101/204520820.html

CPE VDSL modems
* ZyXEL P-871-1/P-871H CPE modems plug into the Zyxel VES-1616F-34-5-band VDSL switch * Prestige P870M-I1 VDSL2 Modem * http://www.buy.com/prod/zyxel-prestige-p870m-i1-vdsl2-modem-1-x-rj-45-10-100base-tx-1-x-rj-11/q/loc/101/204520821.html

Pricing of DSLAMs and VDSL-Ethernet bridges
* Retail price for eight-port mini-DSLAM - $540 : http://www.versatek.com/products/vx1000md.html * VDSL2+ modems: $29 * VDSL/Ethernet bridge: $85 * http://www.zyxel.com is the prefered vendor for VDSL2 DSLAMs.

Aktino: Long-ReachBroadband Over Copper Solutions
http://www.aktino.com/Products.aspx Fiber-like Reliability Aktino products were designed to dynamically compensate for individual copper pair failures. If a copper pair fails, the product automatically adjusts the other copper pair margins to compensate for the loss. This allows any pair to protect all pairs in a bonded group and in many cases can result in meeting or exceeding fiber service level agreements.

Aktino Products Portfolio- Point-to-Point, Point-to-Multipoint Carrier Ethernet and ATM/TDM Solutions. AK5000 Carrier Ethernet Product Family - Cost-effective solutions for 5-100 Mbps ethernet services or backhaul over existing copper loops. Provides symmetric or asymmetric bandwidth and available in point-to-point or point-to-multipoint confifurations. AK3000 Product Family - Cost-effective ATM/TDM solution for service providers to deliver scalable high-quality bandwidth or bakchaul over existing copper loops.

The Metro Ethernet compliant Aktino AK5000 point-to- multipoint product family enables the transport of high-quality, high-bandwidth Carrier Ethernet services over bonded copper pairs. The AK5000 point-to-multipoint line cards bond together 2 to 8 copper pairs creating a symmetrical high-bandwidth link capable of delivering carrier-grade services throughout their networks (12 Kft/ 3.7 Km) and beyond. This environmentally hardened unit is capable of supporting line powering over the same copper pairs that carry the data.

VDSL Ethernet bridges viewed as single port DSLAM
A VDSL bridge bridges or connects two Ethernet based devices upto 1km over TwistedPair. VDSL is an ATM based protocol. One can view a VDSL bridge as a one-port based DSLAM. The VDSL(CPE) converts Ethernet to ATM and transmits it to the other VDSL(CO) who converts the data back to Ethernet. As far as the user is concerned he is transparently interfacing with an Ethernet device on the other end. http://www.versatek.us/products/html/veb150-buy.html. They retail for $85 and achieve 10meg in both directions over TwistedPair upto 3000feet with a range of 7500feet on reduced throughput. This will reduce fiber usage and costs considerably. VDSL/Ethernet bridges can be used instead of DSLAMs depending on the application and data shaping that needs to be done. The VDSL bridge installed at the customer is known as CPE(Customer Premise Equipment). The CPE bridge connects to the CO(CentralOffice) bridge.

Outside plant
* http://www.westek.com/ * http://66.111.101.221/enews/past/view/?issueID=20070717 Backhaul solutions * http://www.telecomosp.com/ Copper splicing outside plant products * http://www.ospmag.com Trade Journal for Telecoms Professionals * http://www.tequipment.net/WilcomTeleTransT124.asp Telecoms testing equipment * http://www.charlesindustries.com/hvdl.htm Outside plant company * http://www.gmptools.com/nf/ OSP stuff * http://www.criticaltelecom.com/products/index.php * http://www.rrdatatelecom.com/rrdata9.html

DSLAM patents
There are 238 DSLAM and VDSL patents on http://www.patentstorm.us. This is directly responsible for Zyxel DSLAM(per port) + CPE modem retailing for $245. We must reverse engineer the circuits via BoMarc and resell it through a FrontingCompany. See DslamOem, DslamAcademic for the companies that will sell VDSL chipsets at minimum quantity of 100 000. For about $300 000 a large DSLAM order can be placed with a DsLamOem such as Connexant.

Capture the Ethernet frame inside the VDSL frame and transmit via OFDM and ATM over copper.

Convergedigest VDSL dslam

 * http://www.convergedigest.com/iptv/iptvarticle.asp?ID=21707