Draft Policy ARIN-2025-6

Fix Formula in 6.5.2.1c

Status: Under Discussion
Shepherds: William Herrin, Gus Reese

Current Text (3 September 2025)

Problem Statement:

Sections 6.5.2.1 explains the initial IPv6 ISP/LIR allocation in a way that is difficult to follow and the formula in section (c) does not match the remainder of the text.

Policy Statement:

In 6.5.2.1c, replace:

“This calculation can be summarized as /N where N = P-(X+Y) and P is the organization’s Provider Allocation Unit X is a multiple of 4 greater than 4/3serving sites and Y is a multiple of 4 greater than 4/3end sites served by largest serving site.”

with:

“This calculation can be summarized as /N where N = P-(X+Y) and P is the organization’s Provider Allocation Unit, X is a multiple of 4 greater than 4/3log_2(serving sites) and Y is a multiple of 4 greater than 4/3log_2(end sites served by largest serving site).

In 2.15 and 2.16, replace “provider assignment unit” with “provider allocation unit.”

Comments: “Provider assignment unit” in section 2.15 was intended to match “Provider Allocation Unit“ in this policy section, but the words fell out of sync.

Timetable for Implementation: Immediate

Staff and Legal Review (9 September 2025)

Staff Understanding: NRPM section “6.5.2.1. Size” describes requirements for the size of IPv6 allocations to ISPs/LIRs. Sub-section “c” defines how to calculate the largest allocation justified by the requestor. Accompanying the text description is a mathematical formula that intends to summarize the calculation as “/N where N = P-(X+Y) and P is the organization’s Provider Allocation Unit X is a multiple of 4 greater than 4/3serving sites and Y is a multiple of 4 greater than 4/3end sites served by largest serving site.”

This draft policy indicates the formula does not match the text, and intends to correct it with, “This calculation can be summarized as /N where N = P-(X+Y) and P is the organization’s Provider Allocation Unit, X is a multiple of 4 greater than 4/3log_2(serving sites) and Y is a multiple of 4 greater than 4/3log_2(end sites served by largest serving site).”

ARIN staff currently implements 6.5.2.1.c based on the text alone. The summarized formula is overly complex for your typical IPv6 requestor. The text alone is more easily understood by customers and implemented by ARIN staff. Modifying the formula would have no impact on ARIN operations. Staff would continue to implement 6.5.2.1.c based on the text alone. Removing the formula from the NRPM would have no impact on ARIN operations, and would simplify the policy language for IPv6 requestors.

NRPM section “6.5.2.1. Size” includes the text “Provider Allocation Unit”, while sections 2.15 and 2.16 reference the term, “Provider Assignment Unit “. This draft policy intends to update the text in sections 2.15 and 2.16 to “Provider Allocation Unit”. Modifying “Assignment” to “Allocation” aligns with the deprecation of Direct Assignment’s that occurred during ARIN’s fee harmonization. Staff agrees the terms should match between section 2 and section 6. Staff currently considers subnetted Direct Allocations, Reallocations, and Reassignments to be “Provider Assignment Units”. This modification aligns with staff’s current implementation.

Implementable as Written?: Yes

Impact on ARIN Registry Operations and Services: None

Legal Review: No material legal issue

Implementation Timeframe Estimate: 3 Months

Implementation Requirements:

• Staff Training
• Updates to public documentation

Proposal/Draft Policy Text Assessed: 3 September 2025

History and Earlier Versions

Related Meetings