Managing Telephone Numbering Resources - Difficult Terrain Ahead?
There are three significant regulatory requirements with respect to carrier management of telephone numbering resources that are lurking over the horizon because of the introduction of Thousands-Block pooling.
The first is the ability to accept and input into TN inventory systems blocks of one thousand Telephone Numbers (TNs) instead of Central Office codes, i.e., blocks of ten thousand TNs.
The second requirement requires TN inventory systems to determine TN utilization in an Exchange Area, which is a new precondition to obtain additional number blocks.
The Third relates to the mandatory return of excess TN inventory.
Obtaining Additional TN Resources
To encourage numbering efficiency and for the early identification of carriers that are not efficiently utilizing numbering resources, Canadian carriers must meet two criteria to obtain additional (growth) TN resources in an Exchange Area as follows:
(i) demonstrate 75% TN utilization in an Exchange Area with every request for additional numbering resources unless accompanied by a CRTC or CRTC staff waiver of the utilization criterion. This recommendation was approved in Telecom Decision CRTC 2025-252 with an effective date in 2027,
(ii) the forecasted months-to-exhaust of existing inventory of available TNs must be no more than 12 months in the Exchange Area assuming no jeopardy condition exists – this is a requirement that existed before Thousands-Bloc Pooling, and
(iii) where Thousands-Block Pooling is in effect, carriers may be required to accept Thousands-Blocks from the Canadian Numbering Administrator (CNA) which have contamination.
Canadian number resource holders will need to be able to correctly intake into inventory contaminated Thousands-Blocks without causing double TN number assignments, i.e., not assigning TNs that are still assigned by the carrier that donated/returned the Thousands-Block. Additionally, carriers will need to be ready to quickly compute utilization of numbering resources in an Exchange Area using a prescribed formula that includes a definition of End User (“End User”), which is defined as a residential, business, institutional, or government entity that subscribes to a service, uses that service for its own purposes, and does not resell such services to other entities. The prescribed definition of End User in turn requires an understanding within the inventory system of which TNs are assigned to resellers.
Are your TN inventory systems ready to receive new Thousands-Blocks? Can your inventory system appropriately compute TN utilization, which is a pre-condition to obtaining additional TN resources?
Return of Excess TN Inventory
In the US, the criteria for the mandatory return (or reclamation) of telecommunications number blocks are strictly governed to prevent TN hoarding and ensure efficient public resource management. Carriers are strictly prohibited from stockpiling idle TNs for future use. Under 47 CFR § 52.20, carriers must maintain no more than a six-month inventory of available TNs in any given rate center or service area.
In the most recent iteration of the CRTC-approved Canadian Thousands-Block (NXX-X) and Central Office Code (NXX) Assignment Guideline (Canadian TBCOCAG), a CO Code Holder or Thousands-Block Holder may return Thousands-Block(s) to the CNA if they are holding excess inventory. Any Thousands-Block selected for donation/return must not have more than 100 TNs that are not currently available for assignment, including TNs assigned to customers, ported-out TNs and TNs used for administrative or routing purposes. The use of the word “may” is problematic as it does not absolutely mandate the return of excess TN inventory. However, it is consistent with the CSCN recommendation in CNRE145A that “LECs and wireless carriers adopt a voluntary block donation process as part of the initial implementation of TBP”. It is generally understood that the optional requirement to return excess TN inventory will become mandatory in the future, similar to requirements in the US.
So what does this mean for a carrier with a TN Inventory system? For starters, any new TN inventory system should allow you to query TN usage at the Thousands-Block level to immediately identify suitable Thousands-Blocks for return to the CNA.
Second, the inventory system should also enable you to compare Thousands-Blocks to see which blocks are easier to return. For example, a Thousands-Block with a Location Routing Number (LRN) would require far more effort to return than a block without an LRN. In another example, consider two Thousands-Blocks with the same contamination level. A block with more ported-out numbers and fewer TNs in use by current customers is easier to return.
Third, the system should let you see exchange-level utilization and forecast data (based at least in part on historical rates of TN assignments) to validate whether you need to be returning TN resources.
Are your inventory systems up for the coming challenges of managing TN resources?
