Regional Scoping with ISO Codes (MeshCore)

Regional Scoping (MeshCore Region Filtering)

MeshCore region scoping (region filtering) lets repeater operators tag flood traffic with a region so that repeaters only forward scoped packets within their configured region, reducing cross-country network congestion. A region is not an ISO 3166-2 code and there is no built-in standard, code table, or official registry inside the firmware. A region is simply an arbitrary, operator-chosen plain name that the firmware SHA-256 hashes into a 2-byte transport code carried in the packet header; repeaters match on that hash.

Communities often adopt ISO-3166-2-style strings such as us or us-co purely as a naming convention. These work only because they are valid arbitrary names - the firmware never interprets them as ISO codes, validates them against any standard, or enforces a country/state hierarchy. Any agreed string works equally well.

How It Works

• A region name is a string of lowercase alphanumeric characters and hyphens (a-z, 0-9, -), maximum ~29 bytes (UTF-8). Within a given mesh, region names must be unique, and they must match exactly - any misspelling is treated as a completely different region.
• The firmware hashes the name (SHA-256) down to a 2-byte identifier. Because the identifier is only 2 bytes, hash collisions between different names are possible (though unlikely for a small set of regions).
• Legacy flood packets that carry no scope are still forwarded everywhere by default - region filtering only applies to packets that carry a scope.
• Since v1.10.0 a basic rule applies: a repeater will not forward a flood packet that has a scope set when the repeater has no matching region. Repeaters running firmware older than v1.10.0 do not honor scopes, so scoped traffic can still leak across them.

This lets a local community (for example, a Colorado group) agree on a region name and keep its scoped traffic within that region instead of flooding the wider mesh.

Configuration Notes

• The number of regions configurable per repeater depends on firmware version. Refer to MeshCore release notes for current limits.
• Region names: lowercase alphanumeric plus hyphen, maximum ~29 bytes (UTF-8), unique within a mesh, matched exactly.
• There is no firmware-enforced minimum scope (no required country + state). Any hierarchy - such as a broad us region plus a narrower us-co region - is purely a convention agreed among operators, not a rule the firmware enforces.

CLI Configuration Example (Colorado)

The names below (us, us-co) are arbitrary example strings, not standardized codes. Defining a region is not enough on its own - you also issue region allowf (allow flood) for each region to actually permit scoped flood forwarding, then region save:

region put us
region put us-co us
region allowf us
region allowf us-co
region save

This configures the repeater with two arbitrary regions (us and us-co) and enables flood forwarding for both. The names carry no inherent geographic meaning to the firmware - they match only because every participating operator uses the exact same strings.

Example Region Names (Convention Only)

The strings below are examples of arbitrary names a community might agree to adopt. They are not ISO 3166-2 codes recognized by MeshCore and are not validated by the firmware - they work only among networks that all agree to use them. Pick any short, agreed name for your local mesh; everyone in scope must use the identical string.

Agreeing on Region Names

There is no central registry built into MeshCore. Choosing region names is a coordination exercise: operators discuss in whatever forums they use (or even over the mesh itself) and come to a consensus on how to divide up their geography. Whatever string you settle on, every repeater that should share that region must be configured with the exact same name.

Third-party community sites such as regionmesh.com publish suggested naming conventions to help operators coordinate, but these are independent community resources, not official MeshCore registries - the firmware neither knows about nor enforces them.

After Changing Region Configuration

After saving region changes, run advert to broadcast the updated configuration to the network immediately rather than waiting for the next scheduled advertisement.