Wholesale: Products & Services

CenturyLink Commercial Dark Fiber (CDF) - V7.0

Note: This product is also known as Qwest® Commercial Dark Fiber (QDF)

History Log

Product Description

CenturyLink Commercial Dark Fiber (CDF) is the wholesale, commercially negotiated replacement product for our CLEC partners' existing, embedded Unbundled Dark Fiber (UDF) base, which in certain circumstances is no longer available per the 2005 Triennial Review Remand Order (TRRO), FCC 04-290 (WC Docket No. 04-313 and CC Docket No. 01-338). CDF is not available for new installation.

CenturyLink Commercial Dark Fiber (CDF) is offered ONLY where and when TRRO rules for non-impairment have been met and CenturyLink is no longer obligated to provision UDF.

CenturyLink Commercial Dark Fiber (CDF) is a deployed, unlit strand or pair of fiber optic strands that connects two points within CenturyLink's network within the same LATA and state. CDF is a single, existing transmission path that terminates on a CenturyLink Fiber Distribution Panel (FDP) or equivalent, between two non-impaired CenturyLink Wire Centers or between any CenturyLink Wire Center and an end user premises, Meet Point or CLEC switch.

CenturyLink Commercial Dark Fiber (CDF) has been provisioned in the following configurations:

  • CenturyLink Commercial Dark Fiber Interoffice Facility (CDF-IOF) is a deployed route between two CenturyLink Wire Centers.
  • CenturyLink Commercial Dark Fiber Loop (CDF-Loop) is a deployed route between a CenturyLink Wire Center and the end-user premises.
  • CenturyLink Commercial Dark Fiber MCDF/ECDF (CDF - MCDF/ECDF) is a deployed route between a CenturyLink Wire Center, and Meet Point facility or CLEC switch.
  • CenturyLink Commercial Dark Fiber Suploop (CDF - Subloop) is a deployed route that is any fractional portion of a Loop.


CenturyLink Commercial Dark Fiber (CDF) is available throughout CenturyLink QC only in offices defined by the FCC as 'non-impaired' where it has been previously provisioned for a CLEC. See 47 U.S.C §§ 51.319(e)(2)(iv). CLECs are not impaired without access to CDF-Loop, dark fiber entrance facilities and without access to CDF-IOF facilities between "non-impaired wire centers". See 47 U.S.C. § 51.319(a) (6).

To view those CenturyLink wire centers that meet the non-impairment criteria established in the TRRO, see CenturyLink Non-Impaired Wired Center Lists for Loops and Dedicated Transport in the Wholesale Interconnection Agreements & Amendments PCAT

CDF is available only on the embedded base of dark fiber services that were in place as of 11/15/05. CDF is available on your embedded base that is in the same state and in the same Local Access and Transport Area (LATA).

Terms and Conditions

CDF products are business-to-business arrangements provided in accordance with commercially negotiated Master Services Agreements (MSAs) between CenturyLink and interested CLEC customers.

Your Commercial Agreement must specifically contain the configuration type prior to retaining the CDF.

Technical characteristics, including Network Channel/Network Channel Interface (NC/NCI™) codes are described in Technical Publication, CenturyLink Commercial Dark Fiber, 77383.


Rate Structure

Long-term contracts are not available. Recurring charges bill on a month-to-month basis, and are comprised of the following elements:

  • CDF-IOF Termination (fixed rate element, per fiber strand or pair)
  • CDF-IOF Fiber Transport (per fiber strand or fiber pair)
  • CDF-IOF Fiber Cross Connect (a minimum of two per fiber strand or fiber pair)
  • CDF-Loop Termination (fixed rate element, per fiber strand or pair)
  • CDF-Loop Fiber (per fiber strand or fiber pair)
  • CDF-Loop Fiber Cross Connect (per fiber strand or fiber pair)
  • CDF-MCDF Termination (fixed rate element, per fiber strand or pair)
  • CDF-MCDF Fiber Transport (per fiber strand or fiber pair)
  • CDF-MCDF Fiber Cross Connect (a minimum of two per fiber strand or fiber pair)
  • CDF-ECDF Termination (fixed rate element, per fiber strand or pair)
  • CDF-ECDF Fiber Transport (per fiber strand or fiber pair)
  • CDF-ECDF Fiber Cross Connect (a minimum of two per fiber strand or fiber pair)

NOTE: CDF Loop rates are applied to service between a CenturyLink Wire Center and End User premises, CLEC switch and Meet Point arrangements.


Rates are available in the Rate Sheet of your MSA.

Tariffs, Regulations and Policies

Tariffs, regulations and policies are located in the state specific Tariffs/Catalogs/Price List.

CenturyLink provides you with access to deployed CDF facilities. You will continue to be responsible for obtaining, maintaining and connecting electronic equipment to both ends of the CDF, and you will continue to be able to use the regenerating equipment that already exists in the facility, if any. CDF technical parameters and related design requirements are described in Technical Publication, CenturyLink Commercial Dark Fiber, 77383.

When CDF is disconnected, the CDF must be returned to CenturyLink in the same condition it was originally provided to you.

You are required to notify and ensure that all of your end-users are disconnected from the CDF prior to your requested disconnect due date.

Optional Features

No optional features are available with CDF.


Features Benefits
CenturyLink's industry-leading telecommunications network and infrastructure.
  • Reliability: Established and highly dependable
  • Volume: CenturyLink transmits approximately 240 million calls across our network daily
  • Experience: An industry leader for over a century.
Products and Services
  • CDF is one of CenturyLink's groundbreaking, commercially negotiated agreements that provide continuity and certainty about the availability of a functionally equivalent replacement for UDF services in non-impaired offices.
Unlimited bandwidth capabilities
  • You can create multiple high bandwidth signals for your end users.


CDF products provide you the opportunity to retain unlimited bandwidth capabilities at competitive, commercially negotiated rates.


Product Prerequisites

If you are a new CLEC and are ready to do business with CenturyLink using alternative products, view Getting Started as a Facility-Based CLEC and Interconnection Agreement (ICA)

In order for CLECs with existing UDF services to request CDF, ICA Amendments to remove non-impaired UDF as well as execution of a MSA are necessary. CDF MSAs are available for execution and currently expire December 31, 2010. To begin the contract amendment process, refer to Commercial Agreements

The transition to CDF from UDF will be efficient. Once you sign an MSA and submit the necessary ASRs which identify circuits included under CDF, CenturyLink will implement rate changes to its billing systems. You will initially receive an invoice crediting you for UDF rates to the Effective Billing Date (EBD) stipulated in the MSA and/or Exhibits. Concurrently, your invoice will be debited for the new commercial Dark Fiber rates to the same EBD.


Pre-Ordering section does not apply to CenturyLink Commercial Dark Fiber.


Requests to convert UDF to CDF and disconnect CDF products use the Access Service Ordering Guidelines (ASOG) forms. Form and field entry requirements are described in the ASOG. The Ordering and Billing Forum (OBF) nationally agree upon the ASOG forms

CDF service requests are submitted using the following Access Service Ordering Guidelines (ASOG) forms:

Access Service Request (ASR) X X
Additional Circuit Information (ACI) X X
Transport Form X X
Service Address Location Information (SALI) form   X

Although additional forms and fields are required, the following field entries identify the order as a CDF product.

Form Name Field Name Definition Valid Entry
ASR REQTYP Request Type. S
SPEC Service and Product Enhancement Code will be populated with the type of CDF being ordered. CDF IOF = UDFTSP
CDF Subloop = UDFSLP
If CDF IOF/CDF Loop premises combination Converting Loop to CDF Loop=UDFLP
Converting IOF and Loop to CDF=UDFTSP
Plus the following in Remarks:
"This is a CDF IOF/CDF Loop premises combination"
TEL NO (IMPCON) Telephone number for the CDF continuity testing contact This field allows 17 numeric characters (including 3 preprinted hyphens)

Maintenance and Repair

CenturyLink cannot monitor CDF inadvertent service disruptions. Such monitoring is normally completed using electronic equipment connected to the fiber provided by you. However, in the case of a major cable failure, CenturyLink will take immediate action to restore all fiber-based services in a cable sheath.

You are responsible for trouble isolation before reporting trouble to CenturyLink. Joint testing between you and CenturyLink may occasionally be necessary to isolate trouble. Both parties will perform cooperative testing to identify where trouble points exist. You are responsible for repairing your cross connections; CenturyLink cross connections will be repaired by CenturyLink.

If it is determined that the CDF does not meet the minimum fiber parameters of Technical Publication, CenturyLink Commercial Dark Fiber, 77383 and the trouble is in the CenturyLink CDF facility, CenturyLink will attempt at no additional cost to repair the CDF as it relates to CenturyLink cross connects and jumpers. If CenturyLink cannot repair the CDF to meet these minimum parameters, CenturyLink will replace the CDF at no additional cost, if suitable CDF pair(s) are available.

General maintenance and repair activities are described in the Maintenance and Repair Overview.


Carrier Access Billing System (CABS) billing is described in Billing Information - Carrier Access Billing System (CABS).


View additional CenturyLink courses by clicking on Course Catalog.


CenturyLink contact information is located in the Wholesale Customer Contacts.

Last Update: January 30, 3017