CenturyLink ATM Service

The security, reliability and privacy your business demands

CenturyLink Asynchronous Transfer Mode (ATM) Service uses state-of-the-art networking technology that enables multi-service solutions to encompass virtually all of your applications. CenturyLink ATM Service runs over a secure, private network and is backed by class of service (CoS)/quality of service (QoS). ATM technology ensures that the most critical traffic receives the greatest resources and the best service. It is designed for multiple locations, using multiple applications within an enterprise network.


ATM services provide a high-speed, secure and reliable solution that integrates your data, voice and Internet traffic over a single network. CenturyLink designs broadband solutions to fit your business needs that can include various ATM Service categories including:

  • Constant bit rate (CBR)
  • Variable bit rate real time (VBRrt)
  • Variable bit rate non-real time (VBRnrt)
  • Available bit rate (ABR)
  • Unspecified bit rate (UBR)

ATM Service uses high-speed ATM networking technology to bundle information into fixed segments called cells, based on industry standards governed by the ATM Forum. The ATM protocol supports many different business applications within an enterprise network, prioritizing each application based on its bandwidth and QoS needs. ATM Service supports speeds from 1.544 Mbps to 622 Mbps. An ATM network can be IP-enabled using optional Smart PVC technology. Smart PVC offers network-based IP-enabled functionality that provides efficient, scalable, high-performance any-to-any connectivity. ATM Service requires the use of customer premises equipment (CPE) that puts customer data into cells suitable for transmission over the CenturyLink ATM network. The CPE must conform to industry standards and be purchased separately from ATM Service.


  • Delivered over a redundant, secure and scalable fiber-optic network
  • Standards-based service levels and QoS objectives to support time-sensitive, mission-critical and burst traffic
  • Inter-working with CenturyLink Frame Relay, CenturyLink IQ Networking and LAN Switching Services
  • Scalable port speeds from 1.544 Mbps to 622 Mbps, including inverse multiplexing over ATM (IMA)
  • Protocol transparent
  • International connectivity to over 30 countries
  • Competitive service level agreements (SLAs)
  • IMA 2xDS-1 to 8xDS-1
  • IP-enabled Smart PVC
  • Web-based customer tools:
    • Control Center for instant access to statistics, alarms management and configurations (based on configuration and location)
    • E-Care for entering and monitoring your trouble tickets (based on configuration and location)


  • Proactive monitoring and network maintenance 24/7
  • Ability to prioritize traffic based on application needs using QoS
  • Supports multiple locations
  • Ability to prioritize traffic based on application requirements
  • Improves cost of ownership by consolidating different business applications on one network
  • Smart PVCs offer simplified, any-to-any connectivity provided via a single enterprise PVC at each customer location (based on configuration and location)

How it works

Customer information travels across a single physical access link (local loop) connecting the customer to the CenturyLink network at an ATM service point. The information (data, video, Internet and/or voice) is segmented into fixed−length cells of 53 bytes (five-byte header and 48-byte user payload). This fixed-length cell gives ATM its efficiency at transporting data quickly. At the ATM service point, information is sent across virtual logical connections simultaneously to multiple destinations. These virtual connections are logical—they are defined in software or in the memory of networking devices. The ATM switching hardware knows where each cell begins and ends. The cell-addressing information is always in the same place, the cell header. By reading some basic information in the cell header, the CenturyLink ATM switch knows where to send the information. The cell header identifies the logical connection and the information is delivered to its destination. The switching hardware makes the routing decision only at connection setup and does not have to make a routing decision for each cell.