Skip to content

Glossary

Terms used across the Fairwave docs. Line-oriented; 3GPP-heavy where noted.

  • eNB - Evolved NodeB: the LTE base station that talks to handsets over the air and to the EPC over S1.
  • gNB - Next-Generation NodeB: the 5G NR base station. Fairwave is 4G-first; gNB is future-gated (ADR-0002).
  • EPC - Evolved Packet Core: the 4G core network (MME, SGW, PGW, HSS) that handles registration, bearers, and data routing.
  • E-UTRAN - Evolved UMTS Terrestrial Radio Access Network: the radio side of LTE (eNB + air interface).
  • MME - Mobility Management Entity: the EPC's control-plane brain (attach, authentication orchestration, paging, tracking areas).
  • SGW - Serving Gateway: anchors user-plane bearers, routes between eNB and PGW.
  • PGW - Packet Data Network Gateway: assigns UE IPs, applies NAT/policy, is the network's internet edge.
  • HSS - Home Subscriber Server: holds subscriber credentials (Ki/OPc, IMSI, profiles) and authenticates SIMs.
  • PCRF - Policy and Charging Rules Function: policy/QoS decisions in the 4G core; Open5GS supports a basic profile.
  • UDM - Unified Data Management: the 5G analogue of the HSS; the roadmap target for subscriber stores.
  • AMF - Access and Mobility Management Function: 5G analogue of the MME. Shipped as part of the free5GC 5G core (core: free5gc).
  • GTP-U - GPRS Tunnelling Protocol, User plane: tunnels user packets between eNB/SGW/PGW.
  • APN - Access Point Name: the named "gateway" a UE connects through; Fairwave defaults are internet and ims.
  • EARFCN - E-UTRA Absolute Radio Frequency Channel Number: numeric channel identifier for LTE carriers.
  • PLMN - Public Land Mobile Network: identified by MCC+MNC; Fairwave default is 999-99.
  • MCC - Mobile Country Code: 3 digits; 999 is the test/dead MCC (never assigned to a real country).
  • MNC - Mobile Network Code: 2–3 digits; 99 in the default PLMN.
  • TAC - Tracking Area Code: locates UEs for paging; Fairwave default is 7.
  • IMSI - International Mobile Subscriber Identity: the 15-digit subscriber identifier on a SIM.
  • Ki - The secret 128-bit key stored on the SIM and in the HSS; never leaves the vault in cleartext.
  • OPc - Operator variant of the OP key; derived from Ki + operator OP per 3GPP; stored like Ki.
  • SQN - Sequence Number: used in authentication (AKA) to resist replay; managed by HSS and SIM.
  • AUX - Not standard 3GPP; in Fairwave docs, auxiliary provisioning data (ICCID, labels) that accompanies a credential.
  • SIM - Subscriber Identity Module: the credential (physical card or virtual) that authenticates a device.
  • eSIM / LPA - eSIM: embedded SIM; LPA: the device software that downloads profiles from an SM-DP+. Fairwave runs a lab SM-DP+ server (see eSIM); production eSIM requires GSMA certification.
  • CBRS - Citizens Broadband Radio Service: US shared-spectrum band (3550–3700 MHz).
  • SAS - Spectrum Access System: the US database/enforcement system granting CBRS channel access.
  • GAA - General Authorized Access: CBRS tier usable without individual license but under SAS rules.
  • PPA - Priority Access License: CBRS tier above GAA, auctioned, still SAS-coordinated.
  • mDNS - Multicast DNS: LAN service discovery; Fairwave uses _fairwave._udp.local.
  • WireGuard - Modern UDP VPN protocol; Fairwave's data-plane mesh fabric (ADR-0004).
  • NAT - Network Address Translation; the edge mechanism behind Fairwave's default local breakout.
  • PoE - Power over Ethernet: how a field small-cell node is typically powered.
  • GPSDO - GPS-Disciplined Oscillator: precise timing reference for real RF; required before real deployments.
  • SDR - Software-Defined Radio: USRP, LimeSDR, BladeRF - the radio front-ends Fairwave supports.
  • ZMQ - ZeroMQ: the virtual-radio transport between srsENB and srsUE in lab mode.
  • EIRP - Equivalent Isotropically Radiated Power: the regulator-facing transmit power figure; spectrum profiles carry EIRP limits.
  • SEPP - Security Edge Protection Proxy: 5G inter-operator signalling gateway; future-work only (roaming).
  • IPX - IP eXchange: the carrier-grade interconnect network roaming traffic flows over; future-work only.
  • LI - Lawful Interception: regulated interception capability; handled per jurisdiction, see regulator FAQ.
  • SPOF - Single Point of Failure: a design anti-pattern Fairwave avoids (e.g. control plane without standby).