Expeto xRouter⚓︎
xRouter is the Expeto core that faces the public mobile networks. Deployed by the Mobile Network Operator (MNO) or in a data centre with IPX connectivity, it is the home network for Expeto SIMs roaming on public radio: it authenticates them, applies the subscriber's policy and forwards their traffic to the xCore that serves their enterprise.
What xRouter does⚓︎
- Home subscriber server. The HSS answers Diameter S6a from the visited networks' MMEs and MAP from 3G networks over the IPX, holds the subscriber records synchronised from xControl, and hosts the SMS centre with SMPP delivery for messaging over the public networks.
- Gateway towards the visited network. The SMF, acting as SGW-C and PGW-C, terminates the GTP-C sessions the visited networks set up over S8, and the UPF forwards the GTP-U traffic on to the public xCore of the subscriber's enterprise.
- Policy and routing. Each session is routed to a downstream xCore user plane by the subscriber's System; the policy engine keeps the routing data in step with xControl.
- BGP. Address ranges are exchanged with the IPX side and with the downstream xCores over BGP, through MetalLB with FRR-K8s.
Network functions⚓︎
The chart deploys these network functions:
| Function | Role in xRouter |
|---|---|
| HSS | Subscriber authentication and data over Diameter (S6a and related applications) and MAP; SMS centre with SMPP. |
| SMF | SGW-C and PGW-C towards the visited networks; selects the downstream xCore user plane per subscriber. |
| UPF | GTP-U forwarding between the visited network and the downstream xCores. |
| NRF | Service discovery between the functions. |
| NFCM | Configuration, monitoring and statistics. |
| UDSF | Session state with the identifier allocator and timer services. |
| Fault manager | Alarm and event handling. |
| Expeto Agent | Connection to xControl: subscriber synchronisation, session records, metrics. |
MariaDB Galera and Redis back the functions; both are installed by the chart.
Deployment model⚓︎
xRouter is installed with Helm as one release per Site. Geo-redundant deployments run one installation per region with the HSS databases replicated between them, so a region can fail or be taken down for maintenance while subscribers stay authenticated. Every installation registers with xControl as a Site of type xRouter, and the same xControl manages the public xCores behind it.
The Installation section covers the cluster requirements, the IPX-facing configuration and the install itself.