PRI - Single Number Service (SNS) Overview:

PRI - SNS is a LATA wide PRI service that is currently available in 31 LATAs within Verizon. (The 31 LATAs are all in the former Bell Atlantic region.) With this service, an ISP could connect to each LATA at one of the designated Interconnection Points in that LATA and would then identify the quantity of PRIs to be terminated at each of the defined Sector Hubs in each of the chosen LATAs, with a requirement to connect to Verizon with a minimum of one PRI in each sector.

Either a 500-699 number assigned by Verizon, or a 555 TN assigned by the North American Numbering Plan Administration (NANPA) would be selected by an ISP. Verizon, using its Advanced Intelligent Network (AIN) platform, would route the call based on a combination of the dialed TN plus the originating TN to the designated sector hub. Calls would then complete over the PRIs connected at the sector hubs via the Interconnection Point to the designated ISP POP.

Customers dialing the 500-699 TN must follow the same dialing requirements as an 800 TN. In many areas, the dialing plan requirement is 1+500-699. Customers dialing the 555 number must follow local calling rules for completing a local call. For example, if there is mandatory 10-digit local dialing, as in Maryland, the user must append the 555 number with the local NPA (e.g., 301-555-2NET). If a local area allows 7-digit local calling, as in Northern Virginia, the customer can dial 555-2NET.

All calls made to the 500-699 or 555 number will be toll free, with no charge over that of a regular local call being charged. For example, if the subscriber pays some type of message unit for a local call, that same charge would apply. If the subscriber has flat rate unlimited service today, no incremental charge would be assessed. Alternately, if the customer has an ISDN line, normal usage charges would apply as well.

CAVEAT: CLECs and Independent Telcos are not required to pass 555 or 500 calls to Verizon. Your customers in those areas would be required to dial a local access TN, or an 800 number, to reach the sector hub for the call to complete. The ISP can, however, use the same 500 or 555 number throughout the entire BA footprint as service is available. In addition, if the ISP chooses to subscribe to PRI-SNS in one LATA, and IPRS with ISNA (Internet Single Number Access) in another LATA, the same 500 or 555 TN can be used with both network solutions.

Interconnection Points, Sector Hubs, & Hub Hopping Configuration:

Each Verizon LATA has several key elements associated with the PRI-SNS deployment:

• Interconnection Point: (ISP) would choose from the Verizon provided Interconnection Point table the closest location to their POP and connect the appropriate quantity of DS3s necessary to support their PRI demand for the LATA.
  
• Sector Hubs: (ISP) would identify the quantity of PRIs required to meet their forecasted demand in each of the Verizon Sector Hubs. Verizon would route all traffic originating from that sector to the PRI trunk group connected to the Sector Hub switch.
  
• Hub Homing Table: Verizon has identified the subtending central offices in each Sector Hub in the Hub Homing Table. In the case that there are remote switches deployed in a given LATA, they follow their associated host switch from a hub homing assignment perspective.
  
• Hub Hopping Table: Each Verizon end office has been associated with a primary hub as identified in the Hub Homing Table. If all PRI ports are busy in that hub, each primary hub has been associated with a maximum of two Alternate Hub locations to which the call will attempt to complete. If capacity is full at both the primary and alternate hub locations, the call will fail, and a busy signal will be returned. This routing configuration is illustrated in the Next Event List Hub Hopping Table. This functionality is planned for a future release date to be determined.
  
• Lead Telephone Number: (ISP) would be assigned a local lead TN associated with each sector hub. (ISP) can use this number to reach their PRIs for access (as in the case of a CLEC switch customer, independent Telco customer, or long distance access) or for diagnostic reasons.
• Default Routing: As identified in the Hub Homing Table, each end office is uniquely associated with one Sector Hub. Based on routing tables built in the Advanced Intelligent Network ISCP, any 500-699 or 555 call originated in an end office will be routed to the designated Sector Hub switch. In the event that the routing table does not recognize the originating TN, and a valid number was dialed, the call will route to a designated Default Sector Hub location for that LATA. The Default Hub location is identified in the Sector Hub table.

Service Transition:

In order to minimize any disruption of service to the ISP's customers, Verizon would redirect the (Verizon) assigned lead dial access numbers currently in use today to the new PRI trunk groups by using the AIN 10-digit trigger. As a future enhancement, for those TNs assigned to the ISP by CLECs (TCG, Brooks Fiber, NE PA Telephone, TC NY NJ, Peco Hyperion, etc.), Verizon would trigger on the dialed numbers using the Local Number Portability (LNP) platform and direct those calls to the new PRI trunk groups. Once the conversion was complete, all traffic would be directed to ISP over the PRIs terminated in each sector hub, and the old PRIs could be disconnected. Verizon would be able to provide ISP with a Hub Homing Table to NPA-NXX Cross-Reference Table to assist in the sizing of the PRI trunk groups.

For more information regarding ISDN PRI:

Former GTE customers please click here
Former Bell Atlantic customers please click here