Digital Subscriber Line (DSL) Interview Questions & Answers

Digital Subscriber Line (DSL) Interview Questions

Do you like to switch your career? Here's our recommendation on the important things to need to prepare for the job interview to achieve your career goals in an easy way. Digital Subscriber Line (DSL) a technology for bringing high- bandwidth information to homes and small businesses over ordinary copper telephone lines. It transmits data faster over traditional copper telephone lines. Candidate should have good command on all functionalities to be done. There is huge demand for jobs related to Digital Subscriber Line (DSL). One can check the availability of the job across cities including Mumbai, Delhi, Bangalore, Pune and Hyderabad. Follow Wisdomjobs page for Digital Subscriber Line (DSL) job interview questions and answers page to get through your job interview successfully.

Digital Subscriber Line (DSL) Interview Questions And Answers

Digital Subscriber Line (DSL) Interview Questions
    1. Question 1. What Is Dsl?

      Answer :

      DSL stands for Digital Subscriber Line. It is a copper loop transmission technology that satisfies bottleneck problem often associated with the last mile between the network and service providers.

    2. Question 2. What Are The Benefits Of Dsl?

      Answer :

      Fast Access - DSL allows you to access the Internet up to 35 times faster than a 28.8k dial-up modem. This means web sites will appear much faster, especially those with large graphics. Your e-mail will arrive and be sent much quicker, and advanced business applications are possible, like web hosting and e-commerce.

      Always On - DSL is a dedicated service, meaning it is always on, so there is no need to dial up to connect to the Internet. No more busy signals and no more waiting to connect. Simply click a desktop icon and you're online.

      Inexpensive - DSL offers high-speed Internet access at a fraction of the cost of other dedicated services, such as a T-1 line. T-1 lines can cost over $1,000 per month, while DSL is priced so that small and medium-sized businesses can afford to buy it.

    3. Question 3. What Do You Understand By "attenuation" In Dsl Technology?

      Answer :

      The dissipation of the power of a transmitted signal as it travels over the copper wire line. In-home wiring also contributes to attenuation.

    4. Question 4. What Is Meant By Upstream And Downstream?

      Answer :

      Downstream means downloading information from the Internet to your computer. Information travels downstream when a web page is loading on your computer screen, or you open e-mail messages that someone sent you.

      Upstream means sending information from your computer to the Internet. Information travels upstream when sending e-mail messages, hosting a web server, providing video streaming, or holding a video conference. If you have ever tried to send an e-mail with a large attachment, like pictures, large spreadsheets, or electronic presentations you understand how a sluggish upstream connection can really slow down your business.

    5. Question 5. What Do You Understand By "bridged Taps" In Dsl Technology?

      Answer :

      These are unterminated extensions of the loop, which cause additional loop loss with loss peaks surrounding the frequency of the quarter wavelength of the extension length.

    6. Question 6. Why Should I Use Instead Of My Phone Or Cable Company?

      Answer :

      There are many advantages to using SYIX.COM over other options. SYIX.COM DSL has been providing Internet Access as a Primary business since 1995 - It's what we do! We do not try to offer you other services such as pay per view movies or long distance services. When we focus on one thing we can provide a level of service you may not get elsewhere. This is the personal level of service. When You call SYIX.COM you will have your call answered by a real person. Our tech support team has the experience to be able to help you. Are committed to providing the highest quality DSL service to our customers.

      • SYIX.COM specializes in providing Internet service.
      • In addition to residential ADSL service SYIX.COM offers a true business class SDSL service. Most local phone companies focus only on ADSL service for residential users.
      • SYIX.COM monitors their network 24x7, which means our customers benefit from high-quality service. 
      • End-users can count on SYIX.COM DSL to work when they need it, without worrying about network downtime or poor quality service.

    7. Question 7. What Is "cross Talk" In Dsl Technology?

      Answer :

      The interference between two wires in the same bundle, caused by the electrical energy carried by each of them.

    8. Question 8. Do I Need To Upgrade My Computer To Use Dsl?

      Answer :

      A Network Interface Card (NIC or Ethernet card) must be installed in your computer. A simple 10BaseT Ethernet NIC will work. Once the NIC is installed it provides a (rj45) jack on the back of the computer allowing you to connect your new DSL modem or router to the computer.

    9. Question 9. Explain Dsl Home?

      Answer :

      DSL Home is an initiative taken by DSL-Forum. To define requirements related to home devices like residential gateways, VoIP devices and local & remote management of home devices.

    10. Question 10. Does Dsl Require Special Equipment?

      Answer :

      Yes. DSL requires that the customer use a special DSL bridge or router (modem - cpe). SYIX.COM sells the DSL Bridge or router you need to get connected to DSL. There are different options available based on the type of service you purchase.

    11. Question 11. Which Services Can Be Enabled By Dsl Home?

      Answer :

      Voice, video, data, including IPTV, video on demand, content on demand, etc...

    12. Question 12. Which Protocol Is Used For Dsl Remote Management?

      Answer :

      DSL Home remote management protocol (TR-69) and its extensions are access agnostic.

    13. Question 13. What If I Want To Upgrade My Dsl Connection To A Faster Speed?

      Answer :

      Call us and we will advise you of options at your location. Normally, you will be able to upgrade to a higher speed service without needing to upgrade your equipment.

      For example: the equipment used for 192 Kbps SDSL is the same equipment used for 1.1 Mbps DSL. However, IDSL, ADSL, and SDSL equipment is not cross functional (an ADSL router would not work on an SDSL line).

    14. Question 14. Which Protocol Is Used For Dsl Local Management?

      Answer :

      The TR64 protocol is used for DSL local management.

    15. Question 15. How Does Dsl Compare To 56 Kbps Analog Modems?

      Answer :

      DSL is significantly faster than a 56 Kbps modem. Also, DSL is always on so there is no need to dial up to connect to the Internet. And because the connection is dedicated you will be able to host a web server whereas this is not feasible with a dial-up connection. DSL also makes it easy to connect multiple computers to one high-speed line to share the speed on that line among an entire office.

    16. Question 16. What Do You Understand By Tr 111?

      Answer :

      TR 111 allows TR 69 remote management for the devices in the Home Network (HN).

    17. Question 17. How Does Dsl Compare To Cable Modems?

      Answer :

      Although cable can be appealing because of its price, there are some inherent drawbacks to cable modem service. First, the cable network is shared, which means as the number of cable users increases the speed on each individual's line decreases. Second, a shared network is inherently less secure than a dedicated service like DSL, as neighboring cable customers can more easily intercept data or hack into another user's computer. Third, the upstream speed on a cable modem is generally no higher than 128 Kbps. Thus, cable modems are unable to provide acceptable levels of speed or security for business purposes.

    18. Question 18. Explain Tr98 And Tr133?

      Answer :

      TR-98 and TR-133: Configuration and Management of Service differentiation (QoS) parameters in the CPE devices through TR-69 and TR-64 respectively.

    19. Question 19. How Does Dsl Compare To A T-1 Line?

      Answer :

      T-1 lines provide access speeds of 1.544 Mbps. The decision between DSL and T-1 access when DSL is readily available is a straightforward one due to pricing. Normally, for the same high bandwidth access, a business will pay significantly more every month for a T-1 line than it would for DSL. Additionally, installation of a T-1 line is generally far more expensive than installation and setup of DSL services.

    20. Question 20. What Is Purpose Of Tr-104, Tr-106, Tr-122, Wt-135, Wt-140, And Wt-142 Protocols?

      Answer :

      • TR-104 Data model for VoIP services is available for Video services too.
      • TR-106 defines the common data model template. Defines the baseline object structure and set of accessible parameters for a TR-69 device.
      • TR-122 defines Voice ATA Requirements.
      • WT-135 is the object model for the STB device.
      • WT-140 is the Object Model Network Storage Device.
      • WT-142 is the framework for TR-069 enabled PON device.

    21. Question 21. How Does Dsl Compare To Isdn?

      Answer :

      DSL will be the cause of ISDN's demise for several reasons:

      • ISDN is only available in two speeds: 64 Kbps and 128 Kbps, both of which are significantly slower than most DSL connections.
      • ISDN sometimes offers dedicated, always-on access but not always. Often, ISDN is subject to additional per-minute fees. Monthly ISDN fees can easily be in the hundreds of dollars.
      • DSL is easier and less expensive to install than ISDN.

    22. Question 22. What Type Of Backbone Equipment Are You Using To Provide Dsl Service?

      Answer :

      SYIX.COM uses an ATM (Asynchronous Transfer Mode) backbone and a DSLAM (Digital Subscriber Line Access Multiplexer) to deliver your service. This equipment is located in Telephone Company Central Offices the DSLAM is manufactured by New Bridge.

    23. Question 23. What Are The Services Offered By Dsl Home- Tr-69?

      Answer :

      The following services are offered by DSL Home TR-69:−

      • Remote management of the devices in a secure manner (uses SSL/TLS based security)
      • Real-time provisioning of services via auto-configuration
      • Status and performance monitoring
      • Diagnostics
      • Access Control
      • Notification
      • Firmware upgrade

    24. Question 24. What Are The Services Offered By Tr-064?

      Answer :

      The following services are offered by TR-064:

      • Adopts the UPnP v1.0 architecture and extends the UPnP IGD v1 specification (with some restrictions).
      • A management application (TR-64 control point) runs on a PC and it pushes the service provider and the customer specific configuration to a CPE. This happens when the CPE adds to the network.
      • More useful during the initial installation of new CPE devices and when there is WAN side connectivity issues.

    25. Question 25. Difference Between Tr69 And Snmp?

      Answer :

      SNMP stands for Simple Network Management Protocol. Use of SNMP requires opening of SNMP port through NAT as most of the home gateways use NAT and the devices being managed could be behind NAT. In SNMP, the request to get/set any parameters is always initiated by the manager hence the port has to be opened on the CPE to get the request. In TR-69, a TR-69 session is initiated by CPE and the server uses the same session to send get/set requests. That does away with opening of the port explicitly in NAT environment.

      TR-69 also defines a way where ACS can send the request to CPE and this part is taken care by TR-111 part2 transparently. Most of the SNMP implementations existing today do not implement SNMPv3, hence the messages exchanged over SNMP is not very secure. In TR-69, the security is taken care through the SSL/TLS or HTTP based authentication schemes. Most of the TR-69 implementations as of today implement SSL/TLS.

    26. Question 26. What Are The Components Of The Dsl System?

      Answer :

      Following are the components of the DSL System:

      • Transport system
      • Local Access Network
      • Multi Service DSLAM
      • DSL Modem/ Router
      • POTS Splitters and Micro filters

    27. Question 27. Explain The Local System In A Dsl System?

      Answer :

      The local access network uses inter-CO local carrier network as a foundation. To provide connectivity between multiple service providers and users of multiple services, additional hardware may be required. Frame Relay switches, ATM switches and / or routers may be provisioned in the access network for this purpose.

      Increasingly, ILECs and PTO are looking for ATM equipment to fulfill this role, and next generation DSLAM include ATM switching to accomplish it.

    28. Question 28. Explain The Multi Service Dslam In Dsl System?

      Answer :

      Residing in the CO environment (or in a space of near virtual collocation), the DSLAM is the cornerstone of DSL solution. Functionally, the DSLAM concentrates the data traffic from multiple DSL loops on the base network for connection to the rest of the network.

      The DSLAM provides backhaul services for the packet, cell and / or circuit-based applications through concentration DSL ON 10Base-T lines, 100Base-T, T1 / E1, T3 / E3 ATM or outputs.

    29. Question 29. Explain The Dsl Modem/ Router In Dsl System?

      Answer :

      The criterion for assessment modem / DSL Router is the customer site equipment to connect the service user to DSL loop. The end point of DSL is generally 10/100Base-T, V.35, ATM, or T1 / E1, with new generations of consumer products also support methods such as USB, IEEE 1394 (Fire wire) and factor internal PCI form.

      Additionally, CPE parameters are being developed with additional ports designed to support specific applications, such as RJ11 ports for support of voice (for e.g. IADs for service VoDSL), ports Video for video services based on DSL, and new networking interfaces such as Home Phone line Networking Alliance (HomePNA) or wireless network such as 802.11 wireless Ethernet interfaces.

    30. Question 30. Explain The Pots Splitter In Dsl System?

      Answer :

      POTS splitters option lie in both CO and service user’s slots, allowing the copper loop to be used for media transmission simultaneously for DSL high-speed data and the single line telephone service, when the DSL variant used these services.

    31. Question 31. Explain The Micro Filter In Dsl System?

      Answer :

      Micro filter is a filter "low pass" that allows voice-band services to be transmitted while filtering the high frequencies used by DSL and eliminates interference.

    32. Question 32. What Do You Understand By The Adsl Technology?

      Answer :

      The following points explain what ADSL technology is:−

      • Discrete Multi-Tone (DMT) modulation used by all ADSL standards for physical layer.
      • Divide the frequency band into many small channels.
      • QAM modulation on each channel.
      • Different bits assigned to each channel in terms of SNR.

    33. Question 33. What Do You Understand By The Radsl Standards?

      Answer :

      The working Group T1E1 ANSI established a standard known as ANSI TR59 RADSL. The FCC has specifically cited RADSL as a technology that is spectrally compatible with voice and other DSL technologies in the local loop.

    34. Question 34. What Do You Understand By The Multimate Symmetric Dsl?

      Answer :

      Beyond the bandwidth of 144 Kbps provided by IDSL, there are new technologies that have emerged that can be better-classified office / small office and residential home (SOHO) possibilities. These technologies offer operating ranges between 128 Kbps and 2.048 Mbps.

      For symmetric applications, MultiMate SDSL (M / SDSL) has emerged as a valuable technology to meet the requirements of carriers to deliver Time Division Multiple (TDM) services on an almost ubiquitous base. Based on the single pair SDSL technology, M / SDSL supports changing rate of command line transceiver and thus the operating distance of the transceiver.

      This version of the CAP supports eight separate rates for a service 64 Kbps / 128 Kbps to 29 kft (8.9 km) 24-gauge wires (5mm) and 15 kft (4.5 km) at a speed of 2 Mbps in full. With a capacity of AutoRate (similar to RADSL), symmetric applications can now be universally deployed.

    35. Question 35. What Are The Benefits Of Reach Dsl (rdsl)?

      Answer :

      Following are the benefits of RDSL:−

      • No POTS splitter is required at the customer premises.
      • In addition to ADSL systems, which can generally reach distances below 18 000 feet from the central office, the Reach DSL systems extend well beyond services 20,000 feet, with some power plants above 30 000 feet.
      • Lower product cost – Since ReachDSL products utilize "off the shelf" rather than customized Digital Signal Processors (DSPs).
      • Dynamic bandwidth allocation – Allows the service to be customized for different applications.

    36. Question 36. What Are The Benefits Of Adsl2?

      Answer :

      Following are the benefits of ADSL2:−

      • ADSL provides up to 8Mbps/800Kbps data rate (possibly 12M/1.2M)
      • Reach of 18-20 kf 26 AWG (about 6000m)
      • No seamless rate change
      • No power saving mode when there is no user activity
      • No 1-bit per bin and partial byte per symbol
      • Fixed 64Kbps overhead channel rate (Framing Structure 3)

    37. Question 37. What Are The Benefits Of Adsl2+?

      Answer :

      Following are the benefits of ADSL2+:−

      • ADSL2+ provides up to 24Mbps/1Mbps data rate
      • Seamless rate adaptation when SNR change
      • Power Management greatly reduce power consumption
      • 1-bit per bin and partial byte per symbol improves reach
      • Reach of 20-22kf 26AWG (about 7000m)
      • Variable overhead channel rate meets user need
      • Loop diagnostic function during training

    38. Question 38. Explain The Benefits Of Adsl2/2+?

      Answer :

      ADSL2 and ADSL2+ deliver next generation features to improve the DSL deployment business case:−

      • Higher Rates
      • Extended Reach
      • Improved Stability
      • Power Management
      • Enhanced Spectral Compatibility

    39. Question 39. Explain The Features Of Adsl2+?

      Answer :

      The following points explain the features of ADSL2+:−

      • Doubles downstream spectrum from 1.1MHz to 2.2 MHz with downstream bin number increased from 256 to 512.
      • Maximum downstream data rate increase from 8Mbps to 24Mbps.
      • Improved performance at short loop length (more on this under Spectrum Management topic).
      • Wider range for SRA and Power Management - from 32Kbps to 24Mbps.

    40. Question 40. What Do You Understand By The Vdsl Access Technology?

      Answer :

      VDSL stands for Very High Bit Rate Digital Subscriber Line. It is the technology that has the highest rate of DSL. Operating at speeds up to 52Mbps, VDSL is the next generation of DSL technology with higher throughput and requirements for implementing simpler than ADSL.

      VDSL began its life being called VDSL, but was renamed VDSL by the ANSI working group T1E1.4. The main reason T1E1.4 decided VDSL on ADSL was that, unlike ADSL, VDSL is both symmetric and asymmetric. VDSL is nearly ten times faster than ADSL and is over thirty times faster than HDSL. The tradeoff for increased speed loop length: VDSL has a shorter reach in the loop.

    41. Question 41. What Do You Understand By Asymmetric Vdsl?

      Answer :

      VDSL is designed to offer a multitude of asymmetric broadband services, including digital television broadcasting, video on demand (VoD), high-speed Internet access, distance learning and telemedicine, to name a few.

      The delivery of these services requires the downstream channel to have a higher bandwidth that the channel upstream and is asymmetrical. For example, HDTV requires 18 Mbps for video content downstream. Upstream, however, it does not require the transmission of signaling information (e.g., change of channel or program selection), which is of the order of kbps.

    42. Question 42. What Do You Understand By Symmetric Vdsl?

      Answer :

      VDSL is also designed to provide symmetrical services for small and medium business customers, business enterprise, high-speed data applications, video conferencing and tele-applications, etc. Symmetric VDSL can be used to provide short-haul T1 replacements NXT1 rate and supports a host of other business applications.

    43. Question 43. What Are The Key Features Of Vdsl?

      Answer :

      Following are the key features of VDSL2.

      DMT modulation:−

      • Same as ADSL
      • Bandwidth increased from 30 MHz (14x ADSL2+)
      • Up to 4096 tones (8x ADSL+!)

      Worldwide Versatile Standard:−

      • 8 Profiles defined for different services
      • Different band plans for different regions
      • Variety of PSDs to optimize spectral compatibility

      Support for a variety of Services:−

      • Integrated Quality of Service features
      • ATM as well as Ethernet payload
      • Channel bonding for extended reach or rate

    44. Question 44. What Do You Understand By Dmt?

      Answer :

      Discrete Multi-Tone (DMT) is a method of separating a Digital Subscriber Line (DSL) signal, so that the usable frequency range is separated into 256 frequency bands (or channels) of 4.3125 KHz each.

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