700 West Mineral Littleton, CO 80120

First Implementation Date: April 10, 1995 Update & Replacement of Network Disclosure Announcement 391.
This document adds additional functionality to Qwest's ATM Cell Relay services. In addition to the DS1 (1.544 Mbit/s), DS3 (44.736 Mbit/s) and OC-3 (155.520 Mbit/s) interfaces, OC-12 (622.08/Mbits/s) and IMA (of 3.088, 4.632, 6.176, 7.72, 9.264, 10.808, or 12.352 Mbit/s) have been added. This update provides additional locations where QWEST plans to deploy Asynchronous Transfer Mode Cell Relay Service (ATM CRS) interfaces including the initial locations for OC-12.  This disclosure replaced Network Disclosure 391. An asterisk in the left margin denotes a change or addition from the previous release.
Summary:	QWEST offers Asynchronous Transfer Mode Cell Relay Service (ATM CRS). Customers access the QWEST ATM CRS via a User-Network Interface (UNI). The UNI is a physical interface between the customer and the QWEST ATM CRS network, but does not determine the bandwidth and throughput available. ATM CRS is a connection-oriented, cell-based switching technology that provides customers with high-speed, low delay information transfer capacity suited for data intensive business computing applications that require near-real-time mixed media communications among multiple locations. QWEST ATM CRS is implemented using Asynchronous Transfer Mode (ATM) cell transfer protocols. This technology provides high efficiency and flexibility because it provides “virtual channels” instead of dedicated physical channels. ATM CRS User-Network Interface: QWEST now supports four UNI physical connections with the maximum bandwidths of 1.544 Mbit/s (DS1), 44.736 Mbit/s (DS3), 155.520 Mbit/s (OC-3), and 622.08  Mbit/s (OC-12).  OC-12 is supported at indicated locations only and is subject to availability.  Qwest also supports IMA (Inverse Multiplexing over ATM) access speeds 3.088, 4.632, 6.176, 7.72, 9.264, 10.808, or 12.352 Mbit/s (this is available wherever ATM has been deployed). ATM CRS Broadband ISDN Inter-Carrier Interface: Carriers can access QWEST's ATM CRS via a Broadband ISDN Inter-Carrier Interface (B-ICI). The B-ICI is the demarcation point that designates the network boundary between service providers. The B-ICI will connect the ATM CRS network to Interexchange Carriers and VANS to provide inter/intra LATA connectivity. Initially, ATM CRS will support two B-ICI physical connections with the maximum bandwidths of 44.736 Mbit/s (DS3) and 155.520 Mbit/s (OC-3). The B-ICI acts as the physical connection to the QWEST ATM CRS network from another cell relay network, but does not determine the bandwidth and throughput available. Permanent Virtual Connections (PVCs): ATM CRS is based on Permanent Virtual Connections (PVCs). No dynamic call establishment or call termination is associated with a PVC. PVC connections are relatively static and are established during the provisioning process. At any time, these connections or paths can be changed via a subsequent provisioning process. Each Permanent Virtual Connection (PVC) ATM CRS is specified as supporting either Constant Bit Rate (CBR), Variable Bit Rate Real-Time (VBRrt), Variable Bit Rate Non Real-Time (VBRnrt), Available Bit Rate (ABR), or Unspecified Bit Rate (UBR) traffic: Constant Bit Rate (CBR) is intended for real time applications that need fixed amount of bandwidth and cannot tolerate any delay. Variable Bit Rate real-time (VBR-rt) is intended for time sensitive applications that need high delivery rate and low delay while allowing for application and network bursts. Variable Bit Rate non real-time (VBR-nrt) is designed for non-real time applications with "bursty" traffic characteristics and able to tolerate delay variation. Available Bit Rate (ABR) supports applications with high throughput at low cell loss of very "bursty" traffic through feedback network congestion control mechanisms. Unspecified Bit Rate (UBR) supports connections which do not specify traffic related service guarantees and is considered a "best effort" service category. UBR is intended for non-real-time applications and provides no service guarantees. VBRrt and ABR traffic are available on DS3, OC-3, or OC-12 access links (i.e. not available on DS1 or IMA connections). The traffic parameter for CBR and UBR connections is the Peak Cell Rate (PCR), which specifies the highest cell rate a customer is provided on a connection. UBR connections do not specify traffic related service guarantees. No numerical commitments are made by QWEST with respect to the cell loss or cell transfer delay for UBR traffic.  ABR traffic also uses the PCR, but adds a Minimum Cell Rate parameter as a feedback mechanism.  VBRrt and VBRnrt connections utilize the PCR, Sustained Cell Rate (SCR) and Maximum Burst Size (MBS). The SCR defines the “average rate” of a connection over a time interval. The traffic parameters chosen by the customer for their CBR. VBRrt, VBRnrt, ABR, and UBR connections are what define the bandwidth and throughput for a UNI. The UNI physical interface of 1.544, 44.736, 155.520, or 622.08  Mbit/s provides the physical connection, but PCR and SCR which define throughput, are the better measurement of the connection capability available to the customer.  IMA  utilizes increments of the DS1 interface (1.544 Mbit/s), and is available in increments of 2 through 8 DS1s. Two types of logical connections (PVCs) are provided by the QWEST ATM Service: Virtual Channel Connections (VCCs) and Virtual Path Connections (VPCs). A VCC exists between two switching points. A VPC is a collection of VCCs switched together as one unit in which the customer has the ability to manage the attributes of the individual VCCs within a contracted aggregate bandwidth. (See Section 3.3 for additional detail.) The single connection topology provided for each connection type is a point-to-point connection that allows bi-directional communication between two end-systems. Virtual Circuit Aggregation: This service is no longer available.
Locations and Timing of Deployment:	ATM Service Points are geographic locations, designated by QWEST, as entry points into the QWEST ATM Service Network.  A list of ATM Service Points can be found under each state specific link located on http://www.qwest.com/disclosures/netdisclosure400/index.html. Wire Centers not listed as ATM Service Points are still accessible using the Private Line Tariff. Mileage and other construction charges may apply.  If the interface changes in the future, QWEST will issue a new Network Disclosure. In addition, any new ATM Service Points will be added to this Network Disclosure 400 and the QWEST Network Disclosure web site. ABR/VBRrt is available at all ATM locations, but limited to UNI Physical interfaces of DS3 and higher.
Interface Requirements:	The ATM Service UNI 622.08 (OC12) Mbit/s and 155.520 (OC-3) Mbit/s, specifications are described in: The ATM Forum, ATM User-Network Interface Specification, Version 3.1, June 1995, (ISBN). This document can be obtained by contacting a local technical bookstore or direct from Prentice Hall. Prentice Hall can be contacted at: Phone: (415) 949-6700 Internet: http://www.atmforum.com Fax on demand: (415)688-4318 OC-12 is supported at indicated locations only. QWEST will not implement this entire interface specification and the exceptions are provided on Attachment #1. The above UNI specification involves those protocols which are either terminated or manipulated at the user-network interfaces. Based on ATM bearer service capabilities defined by the American National Standards Institute (ANSI) and International Telecommunications Union (ITU) standards (acknowledged by the Bellcore Technical References listed on page 5), the UNI protocol layers involved at all UNIs are limited to the Physical and ATM Layers. Section 2 provides the Physical Layer Interface Specifications. Section 3 provides the ATM Layer Specifications. The ATM-CRS UNI, 44.736 (DS3) Mbit/s specifications are described in: ATM Forum Technical Committee, DS3 Physical Layer Interface Specification, March 1996, af-phy-0054.000. This document can be obtained by contacting the ATM Forum at: Phone: (415) 949-6700 Internet: http://www.atmforum.com Fax on demand: (415) 688-4318 The ATM-CRS UNI, 1.544 (DS1) Mbit/s specifications are described in: ATM Forum Technical Committee, DS1 Physical Layer Specification, September 1994, af-phy-0016.000. This document can be obtained by contacting the ATM Forum at: Phone: (415) 949-6700 Internet: http://www.atmforum.com Fax on demand: (415) 688-4318 ATM CRS Broadband ISDN Inter-Carrier Interface specifications are described in: The ATM Forum, Broadband ISDN Inter-Carrier Interface (B-ICI) Specification, Version 1.1, September 1994, af-bici-0013.003. QWEST will not implement this entire interface specification and the exceptions are provided on Attachment #1. The B-ICI specification involves those protocols which are either terminated or manipulated at the network-network interfaces. Based on the ATM bearer service capabilities defined by the American National Standards Institute (ANSI) and International Telecommunications Union (ITU) standards (acknowledged by the Bellcore Technical References listed on page 5, the B-ICI protocol layers involved at all B-ICIs are limited to the Physical and ATM layers. Section 3 provides the Physical Layer Interface Specifications. Section 4 provides the ATM Layer Specifications. The B-ICI document is available by contacting the ATM Forum at: Phone: (415) 949-6700 Internet: http://www.atmforum.com Fax on demand: (415) 688-4318 Virtual Circuit Aggregation Additional technical information the aggregation of Virtual Circuits for DSL Subscribers is contained in QWEST Technical Publication 77392, "Qwest DSL Services". Other Technical Publication References Bellcore Technical Advisory, TA-TSV-001408, Generic Requirements for Exchange PVC Cell Relay Service, Issue 1, August 1993. Bellcore Technical Advisory, TA-TSV-001409, Generic Requirements for Exchange Access PVC Cell Relay Service, Issue 1, November 1993. Bellcore Technical Advisory, GR-1110-CORE, Broadband-ISDN Switching System Generic Requirements, Issue 1, Revision 1, April 1996. Bellcore Technical Reference TR-NWT-001112, Broadband-ISDN User to Network Interface and Network Node Interface Physical Layer Generic Criteria, Issue 1, June 1993. Bellcore Technical Advisory GR-1248-CORE, Generic Requirements for Operations of ATM Network Elements, Issue 3, August 1996. Bellcore Special Report SR-3330, Cell Relay Service Core Features, Issue 2, December 1996. Bellcore documentation can be obtained by contacting: Bellcore Customer Relations 8 Corporate Place, Room 3A-184 Piscataway, NJ  08854-4196 (800) 521-CORE
Additional Information:	Any customer premises equipment vendor/manufacturer or enhanced services provider desiring additional technical information in conjunction with these interfaces provided by QWEST may contact: William Janeck Lead Internet Engineer Network Services Qwest Corporation 700 W Mineral Ave, SD E1410 Littleton CO 80120-0000 United States William.Janeck@qwest.com Office: 303 707-3678 Pager: 303 201-2507 Fax: 303 707-9024

Questions regarding Network Disclosure information can be referred to the individual listed on the Disclosure Announcement, or contact Jamal Boudhaouia, CenturyLink's Manager of Network Disclosures at Jamal.Boudhaouia@CenturyLink.com or (303) 707-8561.