DsLam

http://scratchpad.wikia.com/wiki/Sasecurity

DSLAM as large area LAN
A Dslam connects via TwistedPair copper wire to Adsl modems upto a distance of 5km. The wireing for a DSLAM are laid via TelephoneNetworkRollout. A DSLAM is one of the most powerful network and communications devices on a cost performance basis. Ttat is why http://www.telkom.co.za uses it.

DSLAM is Point-to-Multipoint device
1. DSLAM: Digital Subscriber line access multiplexer 2. A DSLAM is a Point-to-Multipoint device or Router and Switch combination. 3. It is a physical box with ATM protocol based ports functioning as a SwiTch at the back and a Router port at the front. 4. An ADSL modem is an ATM-to-Ethernet protocol converter. 5. A single DSLAM ATM port interfaces with a single ADSL modem which in turn communicates with an Ethernet based device. 6. DSLAM sizes vary between eight and 200 ports. The eight port uses eight RJ-45 telephone jack connectors. The larger port sizes use a Telco-50 connector cable. An ATM DSLAM port connects via TwistedPair(AWG24) to an ADSL modem. 7. 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. A Dslam just like a Router, Hub, Bridge and Switch per se has got nothing per se to do with a Telephone company. All Telcos just happen to use Ethernet based RouTers, SwiTch bridges and the ATM based switch/router combination known as a DSLAM. A community setting up their own telephone exchange via a DSLAM is really just setting up a large area LAN than can radiate out to 5km. 8. The DSLAM can drop and pass network protocols, has QOS, bandwidth increments of 32k and other management features. 9. The ADSL modem hands out a DHCP lease to an Ethernet device.

A DSLAM functioning as a switch and router, receives the ADSL modem data on an ATM port, converts it to Ethernet and streams this data via the Ethernet gigabit link that physically plugs into the DSLAM itself unto an Ethernet based network. The data uploaded to the DSLAM via it's Gigibit Ethernet port is streamed out to the ADSL modem connected to one of its ATM based ports.

The DSLAM can multicast a video stream to all the ADSL modems at the same time. An eight-port DSLAM can stream eight different video streams and at the same time the ADSL modems can upload data unto the DSLAM to be routed unto an Ethernet based network via the DSLAM's Gigabit Ethernet port. This allows for See http://en.wikipedia.org/wiki/Triple_play_%28telecommunications%29 The DSLAM has QOS and bandwidth control in increments of 32k, allowing bandwidth management to each ADSL modem. Download the http:/www.versatek.com Pdf document on their ADSL2+ DSLAMS.

A DSLAM overcomes the distance limitation of 100m over copper wire that limits Ethernet usage. Via the ATM protocol a DSLAM downloads/uploads it's data to the ADSL modem connected to one of it's ports at a distance of over 5km. The ATM protocol uses fixed packet widths. The Ethernet protocol uses variable data rates. As the distance of a wire increases, its resitance increases hence the the need for the ATM protocol between the DSLAM port and the ADSL modem. For FiberOptics the prefered protocol is Ethernet due to its simplicity. ATM is a complex protocol but has to be used for long distance communication over copper.

As the distance of the ADSL modem from the DSLAM increases the throughput will drop. At any distance where the speed becomes unacceptable , connect a Fiber/Ethernet module to the ADSL modem's ethernet port. The Fiber/Ethernet module is essentially a two-port SwiTch. A DSLAM is a viable alternative to many Fiber deployments, it allows people to build their own private telephone exchanges via telephone poles and underground cabling in the exact same manner that a Telco builds their exchanges. The mini-Dslam uses 10 way terminiation Krono-bloks to connect the modems to the Dslam.

Digital subscriber line access multiplexer can also rephrased as: ADSL modems router. BR The word 'Multiplex' obscures the fact that the Ethernet Gigabit upload port at the back of the dslam Routes the ADSL modems connected to its ATM protocol ports(switch) over any network via the Ethernet protocol. So a Dslam should be visualized as a massive 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 or routes their data via the Ethernet protocol unto a computer network that also uses the Ethernet protocol. This has got nothing to do with telephone company backbones, SAI and DigtalLoopCarriers. A backbones and SAI can also be formed using Ethernet based RouTers and SwiTch but because of the distance limitation of 100m over copper with Ethernet, telephone exchanges use a DSLAM. ServingAreaInterface, DigitalLoopCarriers, Backbones and Central Office are jargon terms that only have any semblance of meaning once the various protocols as used by DSLAMs, RouTers, SwiTche and hubs are understood. Upto eight DSALMs 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.

The word ,,subscriber,, confuses the role of a DSLAM. Human beings subscribe to a certain world view. A DSLAM and a network SwiTch are not subscribing to anything, they are interfacing via a communications protocol: Either Ethernet or ATM to another device using the same protocol

Pricing of DSLAMs and VDSL-Ethernet bridges
*Retail price for eight-port mini-DSLAM - $540 : http://www.versatek.com/products/vx1000md.html *ADSL2+ modems: $29 *VDSL/Ethernet bridge: $85 *Versatek sales Engineer: Mr.Hui - USA Tel: 909-591-8891 ext122 *See DslamDistributors for other manufacturers

(in the links below find the M-ANNEXURE which allows 3.5meg upstream)

VDSL Ethernet bridges instead of DSLAM
A VDSL bridge bridges or connects two Ethernet based devices over a long distance. 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 datashaping 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.

See TelephoneNetworkRollout for more info on using VDSL-Ethernet bridges to build a community telephone exchange.

Combine VDSL bridge with DSLAMs
Multiple users either open streets, closed villages, shopping malls and business premises connects their ZoneMinder box to a CPE VDSL bridge. The CPE VDSL streams the CCTV footage to the VDSL(CO) at ServingAreaInterface. The SAI houses a SwiTch,RouTer and DsLam. Each VDSL CO connects to the SwiTch. The SwiTch interfaces with a RouTer. The RouTer connects the the DsLam Gigabit upload port. The DsLam streams the video to the ADSL modems at the CentralOffice. With each DsLam port on ADSL2+ having 24megs available(1km) an eight port mini-DSLAM can stream 192megs total on eight TwistedPair lines. The VDSL cpe,co and DSLAM uses 24 TwistedPair over a combined distance of 2km to stream 192megs. Total TwistedPair length is 24km. At 55c/m this equates to R13200 for the wires alone. ZoneMinder uses Ffmpeg to stream data from the PCs Ethernet port. Using http://ffmpeg.sourceforge.net MPEG-4 streaming allows 1meg per camera. Thus one mini-DSLAM can stream 192 CctvCameras. Fiber is used where the cost of copper is to high. The DsLam for this application could be replaced by a Fiber switch if you only want a point-to-point link. Additional users can be placed on the fiber link using CWDM(course wave division multiplexing). See FiberAndCopper.

Method1: Analogue Video and DSLAM combined
Connect an analogue camera to a VideoBalun. The balun transmitter converts the analogue signal to digital and transmits the video data a distance of 1km over twisted pair copper to the receiver balun which converts it back to analogue. These analogue signals are connected to http://wwww.kodicom.com capture cards installed inside http://wwww.zoneminder.com boxes. The Zoneminder box connects to the DsLam besides it via it's Ethernet port. The DsLam streams the captured video to the ADSL modems. Lightning will be a problem with this setup.

Method2: Analogue video, Internet and Dslam
Six adjacent houses(H1-H6) have a Zoneminder box(marked z) installed, each with four cameras securing their perimeter.(24cameras) H1 streams it's Zoneminder video data using FfMpeg via Ethernet to H3. H3 holds the ServingAreaInterface for H1-H6.

H1,H2..H6 connects it's CCTV data and Internet data to a switch besides. it's Zoneminder box. This switch intefaces with a Fiber/Ethernet module. Dualmode Fiber is run for a short distance to the ServingAreaInterface or telecommunications cabinet. Fiber eliminates the lightning problem from H1 to the ServingAreaInterface. Copper though can be used if buried below ground using a walk-behind VibratoryPlow. http://en.wikipedia.org/wiki/Serving_Area_Interface. At the SAI another Fiber/Ethernet module interfaces with an eight-port switch. This switch plugs into the Gigabit interface of Dslam1. Dslam1,switch and routers are housed inside the SAI.

H1-H6 video streams out via one Dslam1 port over a single TwistedPair suspended from Telkom's Telephone pole to the next DsLam2, 400m away. Dslam2 receives Dslam1 data on it's port via an ADSL modem. Dslam1 has ports available and can receive Internet/video data from Dslam2. By adding an additional TwistedPair two-way high bandwidth communication is possible and either Dslam can function as the http://en.wikipedia.org/wiki/Central_office. Two Dslams linked in this way are protected with lightning surge protectors. H7-H12 connects to Dslam2. Upto eight Dslams can be daisy chained.

Instead of tunneling under the joint perimeter of H1,H2,H3 and H4, bore a hole through the wall and install a galvanised pipe through which the fiber or copper is pulled to connect to the SAI or telecommunications cabinet.

The boxed in houses to the East of H1,H2,H4..H12 can connect via TwistedPair and an ADSL modem to either Dslam2 or Dslam1 open ports by cutting a thin slit through the tar road using the same machine a Traffic officer uses. These machines are avaible for R300/day from http://www.talisman.co.za. The blade is 4mm in diameter.

TARMAN 012 542 2380 informs me that Multiple slits can be cut into the road using these machines and thus multiple ADLS modems can transmit over the road.

Or cut along the length of the road and lay a single TwistedPair, instead of clamping it to Telkom's pole.

Method3: One PIR per camera
Install a genius capture card into a windows box. Connect an outdoor passive infrared PIR besides each camera. On detecting person the PIR routes the camera image to the capture card and over the telephone poles to the operator.

Absolute community control of CCTV
The operators themselves will have a camera trained on them so that anybody with an ADSL modem can watch the control room. Each resident's CCTV data will be encrypted on a PC locked behind a metal enclosure that is itself watched by a camera 24hours a day. You would be able to delete your property's video footage by simply sending an SMS to the control room PC.

See NetworkCentricWarfare for notes on analogue dslam combinations.

Applications and network configurations
25 twisted pair cable bundle for under-roof use: R9/m. Place this cable inside a UV protection plastic pipe to shield from exposure when suspending from telephone poles. Underground cable R19/m(25 twisted pairs inside)are placed inside a PVC pipe which makes it more expensive then telephone pole connected wires. Falcon electronics 021 448 2402 are cable suppliers. ============= It will cost approximately ~R2000/house to connect a 1km stretch of houses to multiple Dslams. Wi-fi: Parabolic, AP, Lm400 cable, climbing on the roof .... R1600. The Dslam expense compares favouribly with Wi-fi but with Dslams you don't need to invent Linux routing protocols, the 2.4ghz spectrum is preserved and Triple-play services are provided - which is impossible with a scrappy 200k Wi-fi link.

There are so many ways to build a hybrid network, for example: Clamp an Adsl modem with an inbuilt 4-port switch to the telephone pole and run Cat5 cable(R1.56/m) to the four adjacent houses. Thus 32 houses can share one mini-Dslam. The R1.56/m cat5 cable isn't UV resistant but is so cheap than one should just replace it as needed. All some people want is just a SIP ethernet VOIP phone, they don't even know how to switch on a PC. Then just connect the SIP phone to the 4-port swithc and route the number to one of the VIOP numbers that Icasa has awarded certain VOIP operators. Just think how that will cut your phone costs - but houses need to cooperate. It's more appropriate to link four adjacent houses via CAT5 then to setup four parabolic/lm400/senao Wi-fi networks on a cost basis alone.

http://www.asterisk.org besides the DSLAM Even people who don't know how to switch on a PC and just want's to use their existing analogue phone will save costs. The wires suspended from our telephone poles connects to an Asterix box where the call is converted to VOIP and unto a stable Diginet line. This alone will save a person the R100/month line rental. Using Icasa's VOIP allocated numbers a person will receive an incoming Telkom landline call from anywhere unto their existing analogue phone. Thus our own telephone exchange/Asterisk combination replaces Telkom's infrastructure. The POTS splitter functionality of the Dslam allows simultaneous Adsl data and voice calls.

ADSL repeaters and Telephone equipment
See DSL talk page on wikipedia. http://www.phylogy.com TripleStreamLine technology to repeat signals. *http://www.phylogy.com/content/Specifications.aspx *http://www.charlesindustries.com are the VAR value added resellers of TripleStreamline *Resellers of TripleStream http://www.at2.com/pages/wanhome.cfm *http://www.charlesindustries.com/main/te_riser_pipe.html *http://www.charlesindustries.com/main/telecom.html