LRN (Local Routing Number) is a 10-digit number that identifies the telephone switch currently serving a phone number. LRN is essential for routing calls to ported numbers, as the area code prefix no longer reliably indicates which carrier serves a number.
How LRN Works
When number portability was introduced, carriers needed a way to route calls to ported numbers. The LRN database (maintained by NPAC) maps each ported number to its current serving switch.
Before routing a call, carriers look up the LRN to determine the correct destination, regardless of the original area code assignment.
Why LRN Matters
- Accurate routing — Ensures calls reach ported numbers
- Carrier identification — Identifies current carrier, not original
- Billing accuracy — Apply correct rates by carrier
LRN Activation Date
VeriRoute Intel provides LRN Activation Date — when a number was last ported to its current carrier. This exclusive data helps detect SIM swap fraud and reassigned numbers.