Yearly Archives - 2015

What is DSLAM?

DSLAM Definition

DSLAM Definition: A DSLAM, or Digital-Subscriber-Line-Access-Multiplexer, is a network distribution device that aggregates individual subscriber lines into a high-capacity uplink. These high capacity uplinks, either ATM or Gigabit Ethernet, connect subscribers to their Internet service providers (ISPs). DSLAM units are typically located in telephone exchanges or distribution points. They allow for the high-speed transmission of DSL technology using legacy copper lines. Using advanced multiplexing techniques, these units salvage the utility of the millions of copper lines that were originally deployed for telephone usage in the 1950’s. DSLAMs also come with many advanced traffic management features to separate and prioritize voice, video, and data traffic. Deploying a DSLAM application diagram

How does a DSLAM connect to customer premise equipment?

DSLAMs are the intermediary units that link end-user equipment to ISP servers located in a central office (CO). ISPs provide end-users with customer premise equipment (CPE) such as routers or modems. These units forward a user’s digital data from their computer or client device to a local cabinet located in the vicinity of a customer’s premise. The data can then travel through a switch, a router, and finally a DSLAM unit.
The DSLAM unit will aggregate or collect individual subscriber lines and transfer data from all their subscribers onto a high-speed capacity uplink that connects to a carrier’s central office using fiber or twisted pair cabling. DSLAMs allow Internet service providers to build Hybrid networks such as fiber to the curb (FTTC) networks. By using fiber for backhaul traffic and twisted copper cables for the last mile of a deployment, ISPs are able to build cost-effective networks that offer high-speed transmission rates. Once data arrives to a central carrier office, information is routed to a broadband remote access server (B-RAS). These units are responsible for authenticating subscriber credentials, validating user access policies, and routing data to their destinations.

DSLAM Classifications

DSLAMs can be classified by the type of xDSL technology they support, by form factor, by architecture, and by deployment location.  

By xDSL Type: Single-Service DSLAMs vs. Multiservice DSLAMs

DSLAMs can be either classified as single-service or multiservice units. Single-service DSLAMs only have the capacity of supporting one xDSL technology. Most single-service system DSLAM units will boast backwards compatibility with previous versions of the xDSL type they support. An ADSL2+ DSLAM for example, will boast backwards compatibility with ADSL2 and ADSL, the two previous generations of the ADSL2+. Multiservice DSLAMs have the capacity of supporting several xDSL technologies. Multiservice DSLAMs allows ISPs or carriers to address the different broadband needs of their customers. For example, a DSLAM chassis that supports VDSL and ADSL line cards gives service providers the advantage of delivering high-speed broadband to customers in short (using VDSL) and long distances ranges (using ADSL). To learn more about the difference between VDSL and ADSL, click here. Multiservice DSLAMs allow ISPs to address scalability, port density and redundant architecture requirements for large-scale deployments.

By Deployment Type

DSLAMs can also be classified by deployment location. A DSLAM designed for outside plant (OSP) deployment such as the VX-M208S, has a smaller subscriber capacity and a smaller form factor in comparison to a DSLAM designed for central office (CO) deployment. OSP DSLAMs are commonly deployed in multi-dwelling units such as apartment complexes or university campuses. These units reside closer to a subscriber’s location and terminate subscriber local loops to achieve faster data transmission rates. “Hardened” OSP DSLAMs provide protection against the elements. CO DSLAMs are located in distribution points and can support up to 10,000 subscriber lines or more. CO DSLAMs typically reside in distributed shelf architectures. These shelf units can host a number of DSLAMs from different vendors and Internet service providers. CO DSLAMs need to fulfill stringent standards due the large number of subscribers they support. Many CO DSLAMs feature a chassis-type form factor with hot swappable line cards. These units allow ISPs to customize their DSLAMs into multiservice units.

By Form Factor

DSLAMs range in size and interface options. Single-service DSLAMs typically deployed in OSP environments, for example, offer a smaller footprint than CO DSLAMs. These OSP DSLAM units are sometimes referred to as pizza boxes to describe standalone units. CO DSLAMs are typically chassis DSLAMs with swappable line cards and uplink modules. Service providers can oftentimes customize these larger DSLAMs with line cards to support multiple xDSL services. This allows them to fulfill different bandwidth demands and subscribers located at varying distances.

By Architecture

DSLAMs can also be classified by architecture. Centralized models reserve a single central uplink card to perform complex traffic processing. Line cards in centralized models hand-off traffic to the uplink card. In comparison to distributed models, line cards in centralized models offer a more basic function. Centralized architectures are designed to support a high number of subscribers. DSLAMs with distributed architectures reserve complex traffic processing for smart line cards that are based on programmable network processors such as linecard traffic processors (LTPs). Uplink cards can be in an Ethernet switch if the unit is used in conjunction with Ethernet backhaul or in a full-featured network processor. Receive a Complementary Consultation  

What is DSL?

DSL provides internet subscribers with high-speed internet access using the same legacy copper lines originally deployed in the 1950’s by traditional telephone lines. DSL relies on DSLAM’s multiplexing capabilities to transmit digital data or analog signals of several subscriber lines using one uplink. Multiservice DSLAMs can support many DSL technologies, but there are currently no DSLAMs that support all xDSL types. DSLAMs can evenly (or symmetrically) or unevenly (asymmetrically) allocate bandwidth between downstream and upstream speeds. One of the major downsides of DSL is that speeds attenuate the farther away a subscriber is located from a telephone exchange or distribution point. But DSL continues to be a popular deployment option due to its low deployment cost and the option to pair with faster cabling options such as fiber. Common xDSL Speeds Comparison Chart

ADSL- Asymmetrical Digital Subscriber Line (ADSL)

ADSL prioritizes downstream traffic and allocates only a small portion of bandwidth for upstream traffic. The original ADSL standard could achieve downstream rates of 8.0 Mbps and upstream rates of 1 Mbps. ADSL2/2+ are the improved version of ADSL. ADSL2 can achieve downstream rates of 12 Mbps and upstream rates of approximately 1.3 Mbps. ADSL2+ can achieve even faster downstream rates at around 24 Mbps and comparable upstream rates with ADSL2. The ADSL standard is normally used for distances of up to 18,000 ft. What is ADSL2

G.lite

ADSL deployments originally required professionally installers to install splitters, or microfilters, to separate the DSL data lines from POTS (plain old telephone connection). G.lite is an ADSL substandard that uses different modulation profiles and does not explicitly require the installation of splitters. G.lite can achieve 1.5 Mbps downstream and 512 Kbps upstream rates (at 10,000 ft). With G.lite, splitters are installed locally inside a subscriber’s homes. The asymmetric standard can achieve distances of up to 18,000 ft.

VDSL- Very High Bit-Rate Digital Subscriber Line (VDSL)

VDSL is optimal for shorter distances and signals quickly attenuate after 6,600ft. VDSL can achieve downstream rates of 55 Mbps and upstream rates of 1.5-2.3 Mbps. VDSL2 can achieve downstream rates of 200 Mbps and upstream rates of 200 Mbps up in the first 1,000ft. While VDSL is considered asymmetric, VDSL is both symmetric and asymmetric. What is VDSL?

SDSL- Symmetric Digital Subscriber Line (SDSL)

Unlike ADSL which unevenly or asymmetrically allocates bandwidth between downstream and upstream traffic, SDSL evenly or symmetrically allocates bandwidth between downstream and upstream rates. With the ability to reach up to 9,800ft, SDSL typically yields around 1.5 Mbps, depending upon the distance of a customer’s equipment. SDSL is ideal for small businesses with more intensive bandwidth use and offers an ‘always on’ connection.

ISDN- Integrated Services for Digital Network

ISDN was the first protocol to integrate data and voice over copper cables and was traditionally used to carry voice for landline communication purposes. The standard supports data transfer rates of 64 Kbps. B-ISDN is an uncommon version ISDN that utilizes broadband transmission and can achieve rates of 1.5 Mbps with fiber optic cables. Additional ISDN substandards include basic rate interface (BRI), primary rate interface (PRI), and narrowband ISDN (N-ISDN).

IDSL- ISDN Digital Subscriber Line

IDSL is a digital transmission-based technology that eliminates the need to travel to a carrier’s central office. The xDSL standard can achieve 128 Kbps over twisted pair copper. Even though IDSL is a subsidiary of ISDN, IDSL allows for always-on connections and offers a more cost-effective option that eliminates setup delays and per minute fees. Transmission of data occurs over the data network as opposed to the PSTN (public switching telephone network).

HDSL- High-bit-rate Digital Subscriber Line

Even though the HDSL standard was first introduced in 1994, HDSL is still widely used by telephone companies and carriers. Performance is comparable to a T1 line though it is more cost-effective. HDSL can travel up to 12,000 ft and deliver symmetric rates of up to 784 Kbps.

Other High-Speed Alternatives To Connect to The Internet

Besides DSL, high-speed broadband can be accessed via coaxial cables, fiber, or wireless connections. The following will overview the different benefits and drawbacks to different internet connectivity methods. Broadband types: pros and cons of DSL,fiber, wireless, and coaxial

Coaxial Cable

Cable originally emerged as a means to deliver access to television programming in mountainous and remote areas. But subscription-based programming did not flourish until the deregulation of the industry in 1984 which spurred carriers to invest “more than $15 billion on the wiring of America” according to this CalCable. But with the widespread adoption of the internet, audiences began to consume content online using popular streaming sites such as Hulu and Netflix. But carriers were able to salvage coaxial lines using DOCSIS standards (data over cable service interface specification). DOCSIS enables carriers to transmit high-bandwidth data using existing cable coaxial wiring used for cable television. DOCSIS standards have significantly evolved and now offer data speeds that are oftentimes faster than DSL. DOCSIS 3.0, can achieve downstream speeds of up to 152 Mbps and upstream rates of up to 108 Mbps. But the newest iteration of DOCSIS 3.1 promises to deliver downstream rates of up to 10 G and upstream rates of up to 1 Gbps in laboratory environments. Real world rates tend to dramatically fluctuate, but improvements like these will continue aiding carriers in providing faster services for their customers. A cable modem termination system (CMTS) in a coaxial network essentially performs the same function as a DSLAM unit in a DSL network. In the same way that a DSLAM feeds subscriber lines to the Internet service provider (ISP), a cable modem termination system (CMTS) feeds the data of hundreds of cable modems and connects users to their ISPs. Cable relies on a shared line architecture and user speeds can drastically decrease during peak usage. However, cable will typically deliver faster rates than DSL. DSL speeds attenuate the farther away a customer is from a distribution point. With coaxial cable connections, however, the distance from a distribution point does not influence speed. Many infrastructures already have coaxial cabling and like DSL, it is relatively inexpensive to connect.

Fiber

Fiber connections offer longer distances and faster transmission speeds in comparison to coaxial cable, wireless, and DSL. Fiber uses light technology to transmit data at up to 1Gbps speeds. Using light technology allows fiber to achieve higher frequencies and data capacities. In comparison to copper-based cabling like DSL and coaxial lines, fiber operates in a near noise-free networking environment with very little interference or energy loss. Fiber optics is also more costly to deploy than DSL or coaxial cabling. Newly built buildings will include twisted pair copper in their infrastructure making it simple for ISPs to provide connectivity using DSL. But fiber is oftentimes deployed after the construction of a building and represents an additional investment. Fiber is also an intrusive medium to deploy—at times damaging subscriber’s property in the most extreme cases. High deployment costs influence carriers to only deploy fiber in high subscriber density areas such as metropolitan areas. To alleviate the high cost of fiber, carriers will oftentimes build hybrid deployments using fiber and twisted pair copper to create FTTC (fiber-to-the-curb) deployments.

WISP (Wireless Internet Service Providers)

Wireless Internet is supported by radio towers that transmit data in the following ranges: 900 MHz, 2.4 GHz, 4.9, 5.2, 5.4, 5.7, and 5.8 GHz. Wireless Internet service providers (WISP) are carriers responsible for providing Internet connectivity to mobile client devices such as cell phones and wireless hotspots. Wireless Internet services are the least common types of deployments. Unfortunately, wireless coverage can be spotty and unreliable. Frequent travelers, for example, may note that performance varies by location during the commute of a train. There are several factors that can influence the performance of a wireless connection including altitude or the physical barriers of a building for example. Receive a Complementary Consultation  

Why DSL Is Still In Use

Twisted copper pairs is a legacy cabling medium that deteriorates with time and can become a liability without proper maintenance. Verizon has been accused of allowing their DSL copper lines to deteriorate so as to pressure residents into adopting fiber. But broadband providers will continue to rely on DSL technology due to low start-up costs. Twisted copper pairs can also be used with fiber to build FTTC (fiber to the curb) deployments using DSLAMs. The most expensive portion of fiber deployment occurs in the local subscriber loop where customer premises are located. To avoid some of the high deployment costs of fiber, carriers will oftentimes build hybrid deployments using copper in the local subscriber loop and fiber in the remaining portion of a network. This form of deployment is known as FTTP (fiber to the premises) or FTTH (fiber to the home). Constant improvements in DSL equipment and chipsets in DSLAMs allow service providers to take advantage of the millions of copper telephone lines that have already been deployed. New chipsets such as G.Fast have been able to achieve up to 1 Gbps at its origin. Improvements such as this will continue to prolong the lifespan of copper pairs.

DSLAM Use Cases

Higher capacity central office (CO) DSLAMs are used in distribution points to continue forwarding packets to their destination. But smaller single-card DSLAMs are also used in customer premises in multi-dwelling units (MDU’s) such as campuses, hotels, businesses and enterprise network environments.

DSLAM Deployment Locations:

  • libraries
  • campuses
  • schools
  • apartments
  • hotels
  • rural areas
DSLAMs optimize high-speed transmission by terminating local subscriber loops and transferring traffic into a high capacity uplink. In other words, connecting a series of modems to a DSLAM allows a higher-quality link such as fiber to take over to connect customers to the Internet.

DSLAMs in Rural Areas

Broadband carriers find rural and remote areas unappealing due to low subscriber density. Areas with low subscriber density offer lower returns of investment in comparison to metropolitan areas that boast higher subscriber density per square mile. The Connect America Funds incentivize broadband service providers to bring high-speed connectivity to rural areas. According to the Federal Communications Commission's (FCC) Connect America Fund (CAF), “approximately 19 million American still lack access” to high-speed broadband. DSL is the preferred type of method in these types of sparsely populated areas due to low startup costs. Internet service providers (ISPs) are able to provide high-speed broadband to a low volume of subscribers using single card DSLAMs such as the VX-M208S or the VX-M2024S. These units are ideal for smaller scale deployments. Different

ATM DSLAMs and IP DSLAMs

DSLAMs rely on ATM and IP packet switching technology to transport data. The following will demystify how the different methods transport information.

Cell Relay

ATM DSLAMs use the ATM protocol to relay data using permanent virtual circuits (PVC’s) to relay data. These PVC’s require configuration to establish a permanent point to point (PPP) connection to a destination using a virtual circuit. The ATM protocol splits data into cells made up of 53 bytes. These cells contain very little routing information due to the PPP nature of PVC connections. ATM networks can transport cells at rates of up to 155 Mbps and 622 Mbps. The ATM protocol establishes a virtual circuit connection from a subscriber to a DSLAM, and then to a B-RAS. The B-RAS then terminates the PPP session and routes traffic to the core network. As broadband began to add more complex data traffic, ATMs began to incorporate a rudimentary ATM switching fabrics, switched virtual circuits (SVCs), and a variety of other traffic management features.

Frame Relay

Broadband now includes many value-added services such as VoIP (voice-over-IP), IPTV (Internet protocol television), VoD (video on demand) and HDTV (high-definition TV). With new concerns for bandwidth, scalability and QoS requirements, IP DSLAMs have managed to consolidate network functions and simplify network deployments. Many IP DSLAMs now have routing capabilities, reducing the number of equipment needed when compared to ATM DSLAM deployments. IP DSLAMs are a cost-effective alternative to ATM DSLAMs. Many service providers opt to build their networks using Ethernet for their backhaul uplinks. Ethernet, such as Metro Ethernet, can be used for both carrier backbone and access network segments. Ethernet DSLAMs, or IP DSLAMs, transmit IP-based data known as frames as opposed to ATM-based packets, or cells. Unlike ATM cell relay, frame relay is a packet switching technology that transmits different sized frames. A frame carries more addressing and error handling identifier tags than ATM packets. Unlike ATM DSLAMs that rely on virtual circuits to relay data to their destinations, IP DSLAMs rely on switches and relay data across constantly-shifting connection paths. However, the frame relay protocol can also be configured to use PVC to forward packets to their destination using permanent pathways as ATM cells do to achieve faster speeds. The growing complexity of broadband traffic such as Triple Play services known as VoIP, IPTV, and HDTV, have made IP-based DSLAMs and IP-Based architectures popular to do their cost-efficiency and simplified network architecture. versa-cta-blog

IP-Based Architectures

Carrier Ethernet, such as Metro Ethernet, can be used for backbone and access network segments. Ethernet standards are constantly being expanded and improved. In fact, the Ethernet Alliance has recently announced new standards for the backhaul of networks:
  • 25 Gbps Ethernet PMD(s) for Single Mode Fiber Study Group
  • 50 GBPS Ethernet Over A Single Lane Study Group
  • Next Generation 100Gbps and 200Gbps Ethernet Study Group
Be sure to visit the Ethernet Alliance website to learn more about these new standards. With constantly evolving Ethernet standards, Ethernet has become an integral component that maintains IP-Based networks cost-effective.

Buying a DSLAM

There are several features that DSLAM buyers will need to take into consideration when weighing different DSLAM options. The main differentiating features are subscriber capacity, throughput, packet loss, latency and jitter.

Subscriber Capacity

DSLAMs provide a range of subscriber capacity. There are three main metrics that dictate subscriber capacity: line density, subscriber and session capacity. Throughput measurements overview a variety of network environment factors that may influence the overall sustainable throughput of a unit including packet sizes, session volumes, and other network environment features such as IGMP snooping, QoS, AAA, and other related features (depending on the capabilities of a DSLAM). DSLAMs support anywhere between a single subscriber to tens of thousands, depending on the type of DSLAM and functionality needed. CO DSLAMs can provide sufficient support for thousands upon thousands of subscribers while OSP DSLAMs can provide sufficient support for as little as one subscriber.

Throughput

Throughput allows carriers to differentiate their service packages from their competitors and is one of the most important factors that carriers take into consideration when deciding which DSLAM to purchase. Though throughput is influenced by a variety of factors, the dominant factor that will determine the performance of a unit will depend on upon the type of xDSL technology used and the location of a customer’s premise. For example, a subscriber that is closer to a central office server of their ISP, will be able to experience faster rates using VDSL2 than a subscriber that lives farther away using the same equipment and xDSL technology. Robust QoS features further improves the accuracy of throughput in real-world settings.

Packet Loss, Latency and Jitter

Broadband has grown in complexity and supports more complex types of traffic such as VoIP, IPTV, and VoD (often known as Triple Play services). These more complex types of traffic are more sensitive to delays or latency and requires more advanced traffic management features to reduce packet loss, latency and jitter. These parameters will influence the performance of a DSLAM. Features such as QoS, Authentication via DHCP Relay, and IGMP Snooping alleviate packet loss. ISPs and network installers can also set the prioritization of voice, video and data traffic to optimize performance. Since voice is more sensitive to delays, incoming and outgoing voice traffic can take priority over data traffic.

Determining the Best DSLAM Units For Your Network

As mentioned before, network installers will need to assess the amount of subscribers they are seeking to serve and the distance ranges they are seeking to cover. DSLAM units come in a variety of sizes with different subscriber capacities. There are a myriad of DSLAM options built for large-scale deployments that can support several thousand subscribers. But there are also single-card DSLAMs that can support a handful of subscribers. DSL performance rates will depend on upon the distance of a subscriber’s location to the central office (CO). DSL performance is mainly dictated by the type of DSL service a DSLAM supports. Installers will most likely choose VDSL/2 services for distances of up to 6,600ft and ADSL2/2+ for distances greater than 6,600 ft. As broadband data has grown more complex, DSLAMs have had to account for value-added triple play services placing greater importance on traffic management features. Common DSLAM features include:
  • Traffic management
  • QoS
  • Authentication via DHCP Relay
  • IGMP Snooping
To demonstrate the range of DSLAM options available, we’ve selected a few examples of different DSLAM equipment types from our product portfolio. These units support varying subscriber capacity and DSL service types.   vx-md4024 VDSL2 DSLAM

24 Port VDSL2 IP DSLAM

Models such as the VX-MD4024 24 Port VDSL2 IP DSLAM are also suitable for small scale deployments. As a network grows in size, additional units from different vendors can be added to a network. These DSLAMs are ideal for multi-dwelling units or external cabinets.   vx-1000hdx ADSL2+ DSLAM

48 Port ADSL2+ IP DSLAM

Devices such as the VX-1000HDx provide longer distances and are designed for access networks. These units are heftier in size measuring around 1.5U.
 Click on the link below to explore our full suite of DSLAM products!
View our DSLAM Products

Chassis-type DSLAM

Chassis-type DSLAMs feature hot-swappable line cards. Service providers can customize these DSLAMs to build multi-service units. Units such as these can feature Gigabit Ethernet (GbE) trunk interfaces and SFP ports for fiber connectivity.

DSLAM Maps

Knowing the approximate location of your nearest DSLAM will help you more accurately gauge the expected speed of your Internet service. But DSLAM maps are very rarely found online. If you’re a potential DSL subscriber, and are searching for a DSLAM map to determine potential speeds, you can contact your Internet service provider. They should be able to give you approximate speeds based on your location.

Configuring a DSLAM

With value-added services such as IPTV (Internet protocol television), VoIP (voice over IP), and HDTV (high definition TV) configuring a DSLAM requires setting the traffic prioritization of voice, video and data traffic. Users will need to configure virtual local area networks (VLANs), QoS, and reserve a set amount of bandwidth for voice—the traffic type most sensitive to latency—on their switches. Uplinks will also need to be connected to the DSLAM Ethernet or fiber port. Users will need to configure data traffic in the following order: First tier: Voice Second: Television Third Tier: Data To preview how to setup a DSLAM, click on the video below:
To view our full DSLAM product portfolio, click here. View our DSLAM Products

Sources:

Understanding DSLAM and BRAS Access Devices by Agilent https://www.quora.com/DSL/Whats-the-difference-between-a-DSLAM-and-an-IP-DSLAM http://www.dslreports.com/forum/r25653574-Need-help-understanding-IP-DSLAM-vs-DSLAM http://www.dslreports.com/faq/6995 https://www.youtube.com/watch?v=3VAmcN8VmIU http://www.informit.com/articles/article.aspx?p=21317  
XDSL speeds

Different xDSL Equipment Overview

DSL has come a long way since its humble ADSL beginnings. The following is the final part in The History of DSL Trilogy. If you missed the Part I discussing the history of DSL, click here.  For a quick overview  of the 6 xDSL technologies in use today, visit Part II of the series.  Receive a Complementary Consultation

Equipment Used For DSL

There are a range of products on the market that deploy DSL services. The following are a few examples of Digital Subscriber Line Access Multiplexers (DSLAMs) and modems that deliver DSL broadband. Visit Part II of this series to learn more about the different types of DSL.

ADSL/2/2+ DSLAMs

Some ADSL DSLAMs are compatible with all three ADSL standards such as the VX-1000HDX and the VX-1000MDX.
best DSLAM

The VX-1000HDX ADSL2+ IP DSLAM unit from Versa Technology is a mini-DSLAM designed for the deployment of access networks.

 
VX-1000MDX

The VX-1000MDX ADSL2+ IP DSLAM unit from Versa Technology is a mini-DSLAM that supports ADSL, ADSL2/2+ AnnexA and AnnexM.

VDSL/VDSL2 DSLAMs

Some VDSL2 IP DSLAMs such as the VX-M2024S and the VX-MD4024 come with ADSL2/2+ ports for added flexibility.  
VX-M2024S VDSL2 DSLAM

The VX-M2024S from Versa Technology is a 1.5U compact 24-port VDSL2 IP DSLAM with 2 Gigabit Ethernet Combo interfaces and built-in POTS/ISDN splitter.

VX-MD4024 VDSL2 DSLAM

The VX-MD4024 is a rack-mountable VDSL2 IP DSLAM. The unit supports two Gigabit Ethernet (GbE) trunk interfaces and 24 VDSL2 ports (ADSLx backward compatible).

VDSL2 Modems

Many VDSL2 modems offers ADSL2+ fallback such as the VX-VER522.
vx-ver522-main-viewWM

Versa Technology's VDSL2 with ADSL2+ fall back 802.11n router has integrated wireless 802.11n draft 2.0 technology, making it possible to provide high-speed wireless data rates of up to 300mbps and superior wireless coverage.

ADSL2/2+

Most ADSL2+ modems support ADSL2 fallback such as theVX-VER170S.  
vx-ver170s-frontWM

The VX -VER170S ADSL2+ bridge/router from Versa Technology provides advanced long Reach/Rate, and crosstalk-free technology.

Limiting Factors

One of the main limiting factors to DSL services is aging copper lines. Companies that seek to compete at fiber speeds like Verizon Communications and AT&T, have been accused of allowing their copper lines to deteriorate so as to replace them with fiber. In fact, Verizon communications has recently sold its wireline liabilities to Frontier Communications, a smaller telecom company that delivers DSL broadband to rural cities.  Another limiting factor to DSL is that subscriber speed directly correlates with how far away subscribers reside from the exchange.

The Future of xDSL

Even though DSL subscribers are declining, ISPs still desire to retain the profitability of copper lines. ISPS are investing in researching new vectoring methods to transmit broadband at faster speeds.  As WinterGreen research reports: “Copper represents an installed infrastructure worth trillions and too expensive to just replace. Fiber is too expensive to use it to replace all the copper.” The utility of copper lines will continue to defy the laws of obsolescence with improved vectoring methods such as G.fast and XG.Fast, which have successfully achieved downlink speeds of 1 Gbps and 5 Gbps respectively. Openreach has already begun trial test runs with the new chipset to determine its integrity in real world settings.  G.fast is still considered bleeding edge technology, but supporting standards such as G.inp promise to stabilize the consistency of signal speeds. To learn more about G.imp click here.  
 

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History of DSL Part 2

A Quick Guide to 6 xDSL Technologies in Use Today

After examining the brief history of DSL, you might be wondering about new multiplexing methods that ISPs have developed to improve transmission speeds via copper lines. The following provides an overview of the most popular types of DSL services in use today. Receive a Complementary Consultation

SHDSL- Symmetric Digital Subscriber Line

SHDSL transmits symmetrical download and upload speeds and is oftentimes compared to ADSL in terms of speed and efficiency. Described as a “business-grade service” SHDSL “comes with guaranteed reserved bandwidth and sync…and has a contention ratio of 1:1”. This guarantees a consistent throughput. SHDSL is not susceptible to congestion. According to Lantiq, “SHDSL-based transceivers can achieve data rates of up to 15 Mbps per copper pair or reach far beyond 15 kilometers (9.3 miles)”.

xDSL SpeedsADSL-Asymmetrical Digital Subscriber Line

Unlike SHDSL, ADSL offers faster download than upload speeds, thus asymmetrical speeds. ADSL reserves more bandwidth for download usage since the typical internet browser consumes more media than he uploads. Having access to faster download speeds more than sufficiently covers the broadband needs of the average user. At its source, ADSL offers downlink speeds of 8 Mbps and can reach as far as 5.5 Km with speed attenuation.

ADSL2- Asymmetrical Digital Subscriber Line

ADSL2 is the second generation of ADSL and offers nearly twice the speed of ADSL. ADSL2 offers a number of improvements including modulation efficiency, coding gain, and dynamic rate adaptation. To view an interactive video about dynamic rate adaptation, click here. ADSL2 requires subscribers to upgrade from an ADSL modem to an ADSL2 modem to adopt the newer standard. Asymmetrical DSL technology can reach download rates of up to 12Mb at its source and can reach as far as 5.5 Km with speed attenuation. Click here for more in-depth information about ADSL2.

ADSL2+

ADSL2+ offers a near two-fold speed improvement over ADSL2.  ADSL2+ boasts a wider bandwidth channel with double the frequency range of ADSL2. ADSL operates in the .14 MHz to 1.1 Mhz frequency range while ADSL2+ operates in the .14 to 2.2 Mhz range. The wider channel bandwidth of ADSL2+ allows it to achieve downstream data rates of 24 Mbps at its source. ADSL2+ can retain downlink rates of 20 Mbps up to distances of 1 km.  For a more in-depth comparison between ADSL2 and ADSL2+, click here!

VDSL-Very High Bit Rate Digital Subscriber Line

VDSL provides considerably faster speeds than ADSL but supports shorter link lengths. VDSL utilizes 25Khz to 12 MHz frequency band and can easily support bandwidth-intensive triple play services such as voice, video, data and high-definition. VDSL2 can achieve up to 52 Mbps at its source and can reliably retain similar data rates up until 300 meters. VDSL however, can reach up to 1,000 meters with attenuated rates.

VDSL2

VDSL2 offers improved vectoring and higher bit rates, as well as faster upload speeds when compared to ordinary VDSL.  VDSL2 vectoring can measure the crosstalk in each binder and generate an anti-phase signal to cancel noise. VDSL2 can provide symmetrical and asymmetrical aggregate data rates of up to 200Mbps downstream and upstream.  VDSL2 occupies frequencies between 2.2 MHz and 12 Mhz. VDSL2 can efficiently reach up to 1.6 km after which performance starts resembling ADSL2+.   XDSL technology has come a long way since its original iteration. To learn more about the history of ADSL, click here
Top 50 Telcom Blogs

The Definitive Top 50 Telecom Blogs and News Sites To Follow

Do you want to become an expert in the telecom industry? Forbes recommends reading daily digests of the top news and blog sites as one of the crucial steps to become an industry expert in your field.  Versa Technology has collected the top 50 sites to help you become an industry expert in the Telecom and computer networking sphere. Do you have other source sites you’d like to recommend? Let us know by leaving a comment below.
  1. Fierce Telecom - Fierce Telecom is an invaluable resource that provides the latest news on telecom companies, backhaul, Ethernet, IPTV, and many other telecom trends. Fierce Telecom is part of the Fierce Market family that covers industries beyond the Telecom sector. All Fierce Telecom sister sites offer an array of resources including live events, webinars, e-books, and many other educational resources.
  2. FierceCable - If you’re a cable provider, visit FierceCable to remain on top of the latest news on voice, video and data service trends.  
  3. Fierce Wireless - Follow Fierce Wireless to access expert analysis of trends in the wireless communications industry.
  4. FierceBigData - FierceBigData targets those in the Enterprise IT sector that work with the exponential growth of data. The site provides news on “data management and analytics, data architecture, big data systems, and other key issues”.  
  5. FierceEnterpriseCommunications - FierceEnterpriseCommunications provides current news in the IP communications to maintain enterprise communication providers up-to-date
  6. FierceITSecurity - FierceITSecurity targets those responsible for maintaining the Cyber Security of their enterprise and is a major news source for topics such as security, malware defense, and many others.
  7. FierceInstaller - FierceInstaller is must-have resource for cabling technicians, outside plant engineers, cell site installers and the many other types of installers in telecom sector.
  8. Light Reading - If the Fierce Market Family didn’t cover so many niches, we’d recommend Light Reading as your number one resource to stay up to date in the telecom sphere. Visit this site to find news and information on anything related to the network communications industry including optical, cable, Ethernet/IP developments, and many other related fields.
  9. Telecomramblings - Telecomramblings is another great b2b resource that provides information on the developments on the infrastructure of the Internet such as backhaul networks, long-haul metro networks, VoIP, unified communications and other industries.    
  10. TelcoProfessionals - TelcoProfessionals is  a great site to network with other professionals in the industry. Resources include news, blogs, summits, and an active community of experts.
  11. Network World - Networkworld aggregates the most important news and blogs in the networking industry. Check out their videos to quickly catching up with the latest trends in high-tech.
  12. EETimes - EETimes focuses on a large sector of the Electronics industry but dedicates a hefty portion of its focus to the wireless & networking sector.
  13. USTelecom - USTelecom is THE Broadband Trade Association that keeps broadband service providers and suppliers informed about the latest broadband news and industry events. If you are interested in a year-round access to professional development events along with the opportunity to collaborate with other Telco professionals, consider joining as a member at their site.
  14. ComputerWeekly - TechTarget acquired Computer Weekly back in 2011. Visitors now have the convenience of browsing TechTarget’s vast knowledgebase directly from ComputerWeekly. ComputerWeekly provides information on any of the IT sectors you may find yourself working in.
  15. LightWave - Light Wave provides b2b information on Network Architecture and Optical technologies.  This site offers a vast library of white appears, videos, webcasts and buyers guides.
  16. Telecom Paper - Telecom Paper is another great resource for finding up-to-date information on the telecom industry offering coverage in the Mobile & Wireless, Internet, Broadcast & Satellite and many more key niches within the Telecom industry.  The research company is based in the Netherlands and will offer limited accessibility to registered members. A one year subscription for a light user will cost you about $212. But this blog offers plenty more free resources. Keep reading!
  17. Telegeography - Telegeography is a market research and consulting firm that provides various online reports.  Research areas include International networks, undersea cables, service providers, and wholesale circuit pricing, (this is another one that might not be worth going to).
  18. TMCnet.com - Tmcnet.com is another great resource for those in the communications and technology industry. The B2b technology site features many industry leaders in the Telecom industry as contributors. Don’t forget to check out their podcast!
  19. Enterprise Networking Planet - If you’re an enterprise IT administrator, Enterprise Networking Planet will provide you with the latest market news and technological advancements relating to routers, software, management tools and information.  Check out their vast library of whitepapers and webcasts.
  20. Telecoms.com - This news portal features international Telecom market news and offers whitepapers and many more resources to keep you up to date.
  21. TelecomEngine - TelecomEngine is a Teleco media group that provides resources beyond market analysis reports. This is another great resource to access insider information on the Telecom markets around the world.
  22. Developing Telecoms - This is another great resource to keep a pulse on the international Telecom markets including Africa, Asia, Central & Eastern Europe, Latin America and the Middle East.
  23. Telecom Lead - Telecom Lead is a Telecom news portal based in India that offers news and stats on the international markets based in Brazil, China, Africa, and the Middle East.
  24. ETTelecom.com - Also based in India, ETTelecom provides another international Telecom news portal that will keep you informed on policies, devices, and the industry in general.
  25. Business Today - Business Today reports the latest news on India’s largest broadband and mobile providers.
  26. TelecomAsia - Telecom Asia brings you the latest Telecom news on the Asian market. Visit Telecom Asia for news on some of the biggest Asian Telecom players including ZTE, Huawei, Fiber Home, and Amdocs.
  27. Telecomstechnews.com - Telecom Tech News provides news and statistics in a range of industries in topics ranging from IoT to Wimax to VoIP. This is an ideal news source site for serving professionals, developers, operators, marketers, outsources and hardware manufacturers.
  28. ItBusinessEdge - IT Business Edge hosts a variety of blogs from industry experts. Get your business edge in IT Management, Data Center, and other essential tools like tutorials, research reports, and other invaluable content for those in the Telecom industry.
  29. SearchTelecom - Like Fierce Telecom, Tech Target covers a broad range of industries that covers  a variety of technology niches. To learn the latest technological and market news in the Telecom industry, visit SearchTelecom. Visit Search Telecom’s to browse through their several niches!
  30. TelecomTimeout Blog - Telecom Timeout Blog is Search Telecom’s very own blog that provides insightful commentary on telecom trends. Have a burning IT/Telecom question? Visit the site and ask the experts! Telecom Timeout offers a vast array of forums, FAQ’s, glossary, and the latest news on the Telecom industry.
  31. SearchNetworking - Another Tech Target niche, SearchNetworking keeps IT professionals updated on the latest news on network infrastructures, backhaul and metro networks, and many more other key topics in the field.
  32. IT Knowledge Exchange - Browse through Search Networking’s blog, IT Knowledge Exchange, that is maintained by networking exporters to provide commentary on the myriad of subjects related to networking.
  33. Whatis.com - Whatis.com is another fun offspring from Tech Target. If you’re interested in becoming a technology word sleuth, sign up for their daily e-mails to receive a tech vocabulary word of the day.
  34. Telco2.0 - Telco2.0 doesn’t have the sexiest web interface, but the blog, maintained by STL Partners, features up-to-date market reports, forecasts, and research papers. STL is a researching and consulting agency that works “at the intersection of the Telecoms-Media-Technology sectors.
  35. Cellular News - Cellular News provides great market watch analysis for the Telecom industry.
  36. Ethernet Alliance - Ethernet Alliance is one of Versa Technology’s favorite sites. Ethernet Alliance provides updates on the latest developments related to Ethernet Standards. Browse through their webinars, videos, whitepapers and press releases and don’t forget to visit their blog to stay in the loop.  
  37. ITNEWS - IT News provides a plethora of information relating to everything related to IT. Follow their news portal to learn about networking, IP communication, cloud computing, operating systems, virtualization, and many more topics.
  38. Jon Arnold’s Analyst 2.0 Blog - Based in Ontario, Canada, John Arnold has been writing about the IP communications sector since 2008. He heads his own independent telecom analyts and marketing strategy consulting firm.  If you work for the communications sector, visit his site for his commentary on new Telecom tech trends.  
  39. Amy Engineer - Amy Renee describes herself as “a network engineer that is recovering from having joined the “dark side” and done exclusively voice for about three years.” AmyEngineer.com chronicles the lessons she’s learned now that her job involves aspects beyond voice.
  40. High Speed Experts - High Speed Experts is a news portal that provides market information and consumer trends on wired and wireless broadband.
  41. The Register - The Register is a UK-based news source site that provides information on science and technology. The Register provides information on networking, data centers, new software, security and many more topics.
  42. KrebsonSecurity - If you’re in charge of maintaining your enterprise network secure, KrebsonSecurity blogs provides the latest news on cybercrime. Brian Krebs is now a New York Times Best Seller having written “Spam Nation: The Inside Story of Organized Cybercrime-from Global Epidemic to your Front Door”
  43. CIO Dashboard - If you’re a Chief Information Officer (CIO) or Information Technology (IT) Director, Chris Curran’s blog has got you covered. CIO Dashboard is the virtual space “Where Technology Leaders Talk”.
  44. Forrester - Forrester is a well-known research company that provides custom market analysis reports and growth strategies. But Forrester also provides great information for CIOs in their CIO blog that features multiple industry experts.
  45. Netwrix Blog - Based in Irvine, California, Netwrix Blog provides a great resource for those concerned with maintaining their IT systems compliant and secure. The corporation is an IT auditing company and their blog keeps IT personnel updated on the latest compliance news.
  46. Data Center Knowledge - Without data centers, we wouldn’t have the luxury of boasting at least 1,2000 Pegabytes worth of information (that’s approximately 1.2 million terabytes according to online sources).  Stay up to date on industry-related news on data-centers with Data Center Knowledge.
  47. Converge! Network Digest - Sign up for Converge! Network Digest’s newsletter to receive daily notifications of international networking news, including wireless and optical technologies.
  48. ConnectWorld - Unlike Converge! Network Digest, Connect World provides expert analysis on current networking trends (as opposed to providing a general market watch).
  49. The Guardian - The Guardian is a British national newspaper that has been a well-respected media group since 1821. Though it has undergone many name changes, the site provides news on Britain telecom companies and great commentary columns. 
  50. Wireless Week - Wireless Week is the go-to-site to get the latest information on devices, carriers, and apps in the wireless industry.

Honorable Technology Mentions

Though we kept our list strictly related to Telecom, we felt compelled to share some great B2C sites besides the obvious Mashable and TechCrunch recommendations (both great sites for tech enthusiasts might we add). Keep reading to explore our Honorable Mentions!
  • The Next Web- Follow The Next Web to get international news on the latest technology and web developments. If you're looking to hone your SEO skills, check out their TNW Academy as well as their TNW Deals and Conferences!
  • Gigaom - Sometimes it’s worth gaining self-awareness of how you and you’re customers are using broadband technologies as consumers. Gigaom is a great resource that will keep you up-to-date on broadband application trends.
  • A Smarter Planet Blog - IBM has again proven itself as a visionary company with its latest venture, IBM Watson. IBM describes Watson as a cognitive assistant “that uses natural language processing and machine learning to reveal insights from large amounts of unstructured data”. In other words, IBM is search engine much like Google and Siri, but on steroids. Visit the site to learn more about the future of Watson’s search capabilities.
  • IEEE Spectrum -  IEEE Spectrum provides the latest discoveries and developments on physics, science, and robotics. If you love futurism, you’ll love this site! IEEE is one of the most well-respected professional association for Engineers boasting over 400,000 members worldwide.  IEEE also oversees the standardization of Ethernet standards as explained here.
  • Fashioning Tech -Wait, fashion and tech are two completely worlds right? Well, if you’re curious about what happens when the fashion and tech worlds collide, check out Fashioning Tech. Take a sneak peek into your future wardrobe with the latest information on smart fabrics, wearables, and other tech innovations in fashion.
  • How To Geek - Ensure to maintain your inner Geek up to date with How To Geek. How To Geek offers tutorials on Apple, Android, and Microsoft platforms and offers a very active forum where you can beleaguer other geeks with your questions.
Did we miss a site? Let us know and leave us a comment below. Don’t forget to follow us on Facebook, Linkedin, and Twitter!  
History of DSL - Part 1

Behind the Obscure History of DSL

If fiber and cable provide faster data rate transmission speeds than DSL services, have you ever wondered why many ISPs offer DSL?

Why We Need DSL

Digital Subscriber Line (DSL) is a type of access technology that delivers high-speed data via legacy copper lines. Internet Service Providers (ISPs) will oftentimes opt for DSL technology to extend the life of legacy copper lines and forego costly infrastructure investments. This post is part of a three-part series that overviews the History of DSL, Different DSL Types, and Different xDSL Equipment Types. Click here for Part II of the series which overviews the different DSL technologies available. Receive a Complementary Consultation Telephone companies initially deployed copper lines to support a booming analog telephone industry.  But with the emergence of new communication modes such as cellular data and the Internet, the demand for landline phones plummeted. As a result, telephone companies pivoted into becoming ISPs and repurposed copper lines to deliver high-speed broadband. But faster access technologies such as cable and fiber have caused DSL’s market share to steadily decline. According to TheNextWeb “DSL is the second-ranked access technology... At the end of June 2013, the 31 million DSL connections, or 34 percent of the fixed broadband market, lost 258,000 lines”. The future of DSL faces a paradox —while deployments are declining, the demand to deliver faster speed via copper lines is on the rise. New copper transmission methods such as G.Fast have achieved up to 1 Gbps in laboratory settings. Evolving DSL technologies such as G.Fast will prolong the utility of the legacy infrastructure. In addition, copper cables can be paired with fiber to create Hybrid Fiber-Coaxial (HFC) deployments, a more cost-efficient alternative to Fiber-To-The-Curb (FTTC) deployments. Though DSL is a mature technology, DSL is by no means obsolete.
 

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The History of DSL

One of the Fathers of DSLEven though telephone companies such as Bell Systems were reaping profits from the monopolization of their industry, the profitability of emerging cable companies lured telephone companies to research new ways to transmit video across their existing copper lines. Once engineers discovered how to transmit digital signals via copper by using a higher frequency, they faced another setback — symmetrical download and upload speeds caused significant interference that delayed data transmission rates. Joseph W. Lechleider, known as one of the fathers of DSL, became part of Bell Labs in 1955. But it was not until the early 1980’s that he proposed to unevenly allocate bandwidth between download and upload speeds. Now known as Asymmetrical DSL, the new technology significantly eliminated electrical interference in copper lines. Unfortunately, the invention failed to create viable competition for cable. Asymmetrical DSL had to wait until the dawn of the Internet to prove its utility. Initially, dial-up speeds more than satisfied early internet browsing functions. But as websites grew more complex and began to use more data-rich content, dial-up speeds would no longer suffice.  Phone companies now had to compete with cable, satellite, and other broadband providers that offered faster data rates. That is when Joseph W. Lechleider’s invention finally came into play. ADSL allowed phone companies to retain a portion of their subscriber-base by boosting data speeds at a fraction of a cost if they were to upgrade to fiber or cable. At the same time, telecom companies did not have to invest in replacing their copper line infrastructures with other expensive (albeit faster) alternatives. To find out more about the most popular types of DSL technology in use today, stay tuned and follow us on Facebook, Twitter, or Linkedin to receive updates for Part II of this series.
What is WLAN roaming?

How to Improve Wi-Fi Reception by Boosting Roaming Aggressiveness

Wireless Local Area Networking (WLAN) automatically connects your client device to an access point (AP) with the strongest signal in an RF environment whose access points have the same SSID. But did you know that you can boost your wireless roaming aggressiveness to increase the frequency at which your client device will search for nearby AP’s broadcasting a better signal quality? Keep reading to find out how! Receive a Complementary Consultation  

What is WLAN Roaming?

WLAN roaming automatically connects your client device to an access point with the strongest signal in an RF environment. WLAN Roaming StandardsWireless network cards in client devices continuously listen for nearby APs with the same SSID. When a client device approaches an alternative AP with a stronger signal, the client can connect to this new AP without triggering service interruptions in e-mail and web applications. (Voice data however, is more susceptible to dropping frames when a client device roams onto a new AP.) WLAN roaming prevents the user from having to re-log back into a Wi-Fi network with the same SSID when it associates with a new AP. This makes it simple for a WLAN client to take their laptop from a sales department for example, and bring it into different locations, such as a warehouse, without having to re-login to a different wireless access point.    

How does WLAN roaming work?

When a wireless client device approaches an AP with a stronger signal, the client device must associate with the new AP and disassociate its connection from the old AP. This process is known as the “handoff” process that occurs automatically.  The “handoff’ process consists of the following steps: Step 1: Scanning When the RSSI (Received Signal Strength Indicator) values begin to drop in a client device, it will search for nearby APs with the same SSID that are broadcasting a stronger signal. Step 2: Authentication If the client device finds an available AP, it sends a request to access the new AP. The client device patiently waits to get approved or rejected by the new AP. Step 3: Re-Association If the new AP approves the request, the client will send a re-association request and complete the hand off process by disassociating from the old AP. How long does the handoff process take? The handoff process is typically unnoticeable by the user and takes less than ½ a second.

What is roaming aggressiveness and how can it improve my wireless reception?

Roaming aggressiveness refers to the interval time and conditions that will trigger a wireless network card to search for and connect to an alternative AP. Boosting your roaming aggressiveness increases the rate at which your network card will seek out an AP with a stronger signal. Adjusting roaming aggressiveness adjusts the sensitivity of your wireless network card to nearby APs.

Who can benefit from adjusting roaming aggressiveness?

Users using a shared Wi-Fi network in a small business, enterprise, campus, or a home with multiple access points can benefit from WLAN roaming.

Are there any downsides to adjusting wireless roaming aggressiveness?

The only downside is that there is no quick way to simultaneously adjust the wireless aggressiveness of several client devices. IT departments in a campus that lends laptops for example, will need to set up the wireless aggressiveness of these client devices individually.

How Do I setup Roaming Aggressiveness on my computer?

Click the video to learn how to setup your roaming aggressiveness! https://www.youtube.com/watch?v=5WOR6I_haDk The following steps will show you how to change your roaming aggressiveness on Windows PC:
  • Navigate to the Start Menu to access your Control Panel
  • Click on Network and Internet
  • Click on Network and Sharing Center
  • Under Connections select Wi-Fi
  • Click Properties
  • Select Client for Microsoft Networks
  • Click Configure
  • Click the Advanced Tab
  • Select Roaming Aggressiveness
  • Select your preferred Value from the drop down menu.
Please note: If you are using a Ralink Wi-FI network adapter, click Roaming Sensitivity and select your preferred Value from the drop down menu. Ralink uses the term roaming sensitivity instead of roaming aggressiveness. Setting your roaming aggressiveness to a higher value will trigger your client device to look for APs more frequently. Your client device will not roam when set to the lowest setting unless it experiences severe link quality degradation.

Will this tutorial work with any laptop?

This tutorial will work for laptops that have Intel and Realtek networking cards.

How do I setup Roaming Aggressiveness on my phone?

Not all cell phones have been natively optimized to set up roaming aggressiveness. If your cell phone uses an Android platform, you may be able to install WiFi Roaming Fix, a third-party app that allows users to tinker with their roaming aggressiveness. For a more in-depth tutorial to Wi-FI Roaming Fix, click here. Did you know that Elon Musk is supporting an entrepreneurial initiative to build micro satellites that will transmit Internet access “to the unfettered masses”? Click here to find out more!
Internet of Things Infographic

How much Data will The Internet of Things (IoT) Generate by 2020?

The Internet of Things (IoT) has exploded over these past three years, and according to Gartner research, 25 billion connected “things” will be connected to the Internet by 2020. With the influx of smart technology, IPV6 will provide enough IP addresses to more than sufficiently cover the evolving digital life of consumers. The Smart Homes sector alone is predicted to be a $490 billion market. But consumer-brand manufacturers will not be the sole beneficiaries of the IoT explosion. Gartner predicts that the manufacturing, healthcare, and insurance industries are the top three industries positioned to profit the most from the IoT sector. IoT has given our physical inanimate world a “digital nervous system”, a term coined by Bill Gates & Judith Dayhoff. The vision anticipates a deluge of information generated from smart appliances to smart infrastructures. This already emerging hyper-connected environment will monitor, measure, and automates tasks and increase the demand for big data analytics. The following infographic provides a sneak peek into the exponential expansion of the IoT movement.     IoT infographic
adsl2/2+ FAQ

The 11 Most Frequently Asked Questions About ADSL2 & ADSL2+ Answered

ADSL2 and ADSL2+ technologies have enabled ISP providers to provide their customers with high-speed broadband via legacy copper lines.  We've compiled a list of  the 11 most commonly asked questions about ADSL2 & ADSL2+ to demystify the Digital Subscriber Line (DSL) technologies. If you’re interested in learning more about VDSLs, visit our VDSL/2 FAQ here. Receive a Complementary Consultation

1. What is ADSL2/ADSL2+?

ADSL2 and ADSL2+ are DSL technologies that deliver high-speed broadband using Plain Old Telephone Services (POTS). Copper telephone wires consist of at least 25 or more twisted wire pairs making transmission signals susceptible to crosstalk. ADSL2 and ADSL2+ utilize sophisticated modulation technologies to eliminate noise and interference in transmission signals. This allows for relatively error-free transmission via legacy copper lines.

2. How fast is ADSL2?

Actual speeds vary depending on networking environments and copper loop lengths. ADSL2 can achieve downstream data rates of up to 12 Mbps speeds at its source while ADSL2 can achieve up to 24 Mbps. ADSL2/2+ are best suited for longer loop lengths. ADSL2 can reach distances of up to 5,000 meters while ADSL2+ can achieve up to approximately 6,000 meters. Refer to the chart below to compare ADSL2, ADSL2+, and VDSL2 speeds. ADSL2/2+ vs. VDSL Speed Comparison Chart

3. What is the farthest ADSL2/2+ can reach?

ADSL2 can reliably support high-speed broadband to loop lengths as far as 5,000 meters while ADSL2+ can achieve slightly longer distances at 6,000 meters.

4. What are some ADSL2 improvements?

ADSL2 improves:
  •         Modulation Efficiency
  •         State Machine Initialization
  •         Coding Gain
  •         Signal Processing Algorithms
  •         Framing Overhead Reduction
  •         Seamless Rate Adaptation (SRA)
Seamless Rate Adaptation (SRA) allows the transceivers to adjust transmission rates according to changing networking conditions in real-time. SRA is a functionality that allows ADSL2 to decouple packets in the modulation layer while maintaining the framing layer parameters intact. This preserves the synchronicity of the information transmitted while modulation rates are adapted.  

5. Are ADSL2/2+ DSLAMs energy-efficient?

Yes. Most ADSL units provide consistent power feeding which not only wastes energy and resources but also increases heat dissipation which can damage equipment after prolonged usage. ADSL2 provides two energy-efficient power modes: L2 and L3 low-power modes to help conserve energy.  The L2 low-power mode can adjust power based on the traffic demands of an individual-per-use-case. ADSL2 units will kick into full power mode during traffic intensive applications such as occurs when downloading large files and revert back to L2 low-power mode when the surplus power is no longer necessary. The L3 low-power mode puts the transceiver at the Central Office (CO) to sleep after a period of inactivity.  

6. How does ADSL2/2+ achieve high data rates?

One of the features that enables ADSL2/2+ to achieve high data rates is channel bonding. ADSL2/2+ has the capacity to bond several telephone phone lines together to achieve higher bandwidth. ISPs can bond several channels to achieve a wider bandwidth and increase downstream and upstream data rates. Channel bonding resembles the process of adding more lanes to a freeway so that it can support more traffic. This flexibility enables Internet Service Providers (ISPs) to offer different tiered data rate services to subscribers.

7. Are ADSL2/2+ units compatible with previous versions of ADSL2?

Units with the “ADSL2 fallback” feature provide support for previous versions of ADSL standards. Units will revert to previous standards if connected to devices that support older standards so as to preserve compatibility.  

8. What is the difference between ADSL2/ADSL2+?

ADSL2 and ADSL2+ are variations of the same technology. ADSL2 utilizes frequencies between .14 MHz and 1.1 Mhz. ADSL2+ offers double the frequency range, between .14 Mhz and 2.2 Mhz. The wider channel bandwidth of ADSL2+ doubles its downstream data rates. ADSL2+ technology also has the capability of eliminating crosstalk. Since ADSL operates between the .14 to 1.1 Mhz frequency range, ADSL2+ will automatically transmit signals on the 1.1 to 2.2 range to prevent crosstalk. This functionality is especially useful when both ADSL2 and ADSL2+ services are present in the same binder on course to a customer’s premises.

9. What is the difference between Annex A vs. Annex B?

ADSL over POTS, more commonly known as Annex A, is used in North America. Europe on the other hand, utilizes Annex B which delivers ADSL over ISDN.  Annex A and Annex B provides approximately  24 D / 1.4 U Mbps rates.

10. What is the difference between Annex A vs. Annex M?

Also known as ADSL2 M and ADSL2+ M, Annex M provides a slight improvement in upstream rates when compared to Annex A. Annex M yields up 3.3 Mbps upstream data rates as opposed to the typical upstream rates of 1.4 Mbps in Annex A.

11. How old are the ADSL2/ADSL2+ standards?

The G.992.3 and G.992.4 ADSL2 standards were introduced in July 2002. The G.992.5 ADSL2+ standards received official standardization in 2003. Did you know that copper lines can now transmit gigabit speeds in laboratory settings? Find out more about the up and coming G. Fast technology here.
Li-Fi in Hospitals

They Tried to Transmit Brain Scans Using Li-Fi LED Lights And it Worked!

Li-Fi is a relatively new connection method pioneered by Researcher Harald Hass from the University of Edinburgh that can connect users to the internet using LED Lights. Receive a Complementary Consultation But researchers from Pukyong National University seek to research and adapt this new technology for medical usage. Successful Li-Fi implementation in hospital environments will make it possible to eliminate the need for medical devices to rely on wired connections to achieve internet connectivity.

Li-Fi Use Cases in Medical Environments

Researchers have been able to successfully transmit electroencephalogram (EEG) brain signals via Li-Fi.  IEEE spectrum reports that “power ranged from one half to 100 millivolts, and frequencies between one half and 45 hertz”. RGB sensors were used to amplify these weak signals and to filter distortions. The research team has also been able to obtain Electrocardiogram (EKG) readings — a medical device that reports the electrical activities of the heart.  Li-Fi could also potentially support Electrooculography (EOG), a technique that measures the distance between the front and back end of the eye.Li-Fi in the Hospital

Li-Fi Outperforms Wi-Fi Hands Down

Li-Fi, short for Light Fidelity, avoids the crowded RF spectrum and can transmit information at a faster rate than wi-fi. Gizmag reports that researchers from the Autonomous Technological Institute of Mexico (ITAM) have successfully been able to “transmit audio, video and internet at rates of up to 10 gigabits per second”.

But Researcher Harald Haas has taken his technology one step further and is experimenting with replacing LED lights with laser diodes to achieve “beyond 100 Gb/s.”

Advancements in Li-Fi technology might just make your next visit to the doctor a wireless affair powered by Li-Fi LED lights.  
Fastest Ethernet Extender

Fastest Ethernet Extender Achieves Wire Speed of 300 Mbps

Versa Technology is proud to announce that we will be offering the VX-VEB160G4 (V2), an Ethernet Extender Kit that can achieve transmission rates of up to 300Mbps (190 Mbps DS / 110 Mbps US).  The VX-VEB160 (V2) is the fastest Ethernet Extender Kit available in the market today with a near two-fold improvement in performance over the first generation (100 DS/100 US Mbps). The second generation Ethernet Extender Kit, the VX-VEB160G4 (V2), allows users to achieve near fiber-like speeds via existing copper lines. These units give network administrators an appealing alternative to fiber deployment. Receive a Complementary Consultation  

Different Modes For Different Applications

Our fastest ethernet extender gives users the ability to customize the performance of their units. With two selectable VDSL2 profiles, users can choose between Profile 30’a High Throughput Mode and Profile 17a’s Long Reach Mode. The following chart summarizes the different transmission speeds the VX-VEB160G4 (V2) can achieve:
Fastest Ethernet Extender

The VX-VEB160G4-V2's Speed Performance under 17a and 30a modes.

Our second generation Ethernet Extender Kit makes it simple to upgrade a network with its plug-and-play installation. By simply connecting the VX-VEB160G4 (V2) to a network and the desired network device, network administrators can effortlessly  add up to 9,000 meters and still achieve up to 4 (Mbps). This unit makes it simple to extend the distance of a network connection allowing users to bypass the standard 100m Ethernet limitation with a simple plug-and-play installation.

Industrial Performance That's Simple To Use

The VX-VEB160G4 (V2) is ideal for industrial environments with the ability to support wide operating temperatures ranging between -40°C to 75°C. These units offer stable performance in harsh environments giving network administrators the ability to extend networks at any location. The unit features 4 Gigabit interfaces (RJ-45 connector) and 1 VDSL2 interface (RJ-45 connector) enclosed in a metal encasement.
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