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Roaming and Multi-Operator Interconnect: Future Work

This page is deliberately unambitious. Fairwave v0.1.0 does not do inter-operator roaming, and the roadmap does not claim it. Here is the honest state and what it would take.

What exists today

  • Intra-mesh peering: UEs of one operator traverse another operator's nodes only within a single administrative mesh, under explicit policy (see peering). This is not roaming - no settlement, no inter-operator identities.
  • PLMN separation: each deployment serves its own PLMN; there is no N26/interface exchange between PLMNs.
  • No SEPP: the Security Edge Protection Proxy (5G) or GRX/IPX connectivity required for real-world inter-operator signalling does not exist in the codebase.

What "roaming" would require (honest list)

  1. Contractual basis. Roaming is a commercial and legal arrangement: settlement agreements, fraud handling, LI obligations, data protection (GDPR/DPA scope). Software cannot supply this.
  2. SEPP or MAP/GRX interconnects. For LTE: S6a/S8 over a trusted GRX/IPX exchange with certificate chains (STKS, network certificates). For 5G: SEPP with security parameter negotiation (PRINS). Fairwave has neither implemented nor certified.
  3. HSS/UDM federation. S6a/S13d reachability, roaming IMSI ranges (MCC/MNC of visited networks), VLR/MME addressing, and AVP-level compatibility with host network elements.
  4. Charging and settlement. Inter-operator TAP/NA records - none shipped. Note: per-UE offline charging is produced today by the free5GC CHF (TS 32.297 CDR files, consumed by fairwave-control for fair-use metering) - that is a metering source, not a roaming settlement format.
  5. LI and lawful access. Host-country requirements for retained data and interception of roaming subscribers must be met by both operators; see the regulator FAQ.
  6. Testing. Actual interop testing with a real MNO's core or a certified test lab - not simulated.

Roadmap posture

Milestone Scope
v0.1 (lab) No roaming. Mesh peering within one admin domain only.
v0.1 (5G mode) Per-UE offline CDRs from the free5GC CHF, used for fair-use metering (not inter-operator settlement).
M4 Interchange formats documented (CDR export schema) for community settlement experiments.
M5 SEPP interface contract documented as an integration point (ADR-0011 style contract), no implementation committed.
M6+ Only with a licensed partner: pilot of one-to-one roaming via a certified IPX provider.

Nothing in M0–M6 implies roaming is shipped. If a page or talk says otherwise, it is wrong.

What Fairwave-compatible boxes can do lawfully today

  • Offload / neutral host experiments: one operator's node serving subscribers of another only through lawful MVNO-style arrangements (subscribers hosted in the local HSS under contract). This is the realistic path: local breakout with hosted identities, not inter-operator signalling.
  • Community settlement prototypes: CDR-style accounting via the sessions API (and the CHF CDR files in 5G mode) for voluntary clearing between community operators - data-plane settlements, no core-to-core interconnect.

If you are an MNO reading this

  • Fairwave meshes are private networks, not a roaming threat; there is no inter-PLMN path out of the box (see carrier FAQ).
  • The integration surfaces that exist - Open5GS-standard S6a/API, documented CDR exports in M4 - are the only interop points.