The VAS Experts ePDG Monitoring system provides full operational control of the fast-epdg component, the VoWiFi (Voice over WiFi) gateway operating according to 3GPP TS 29.273 and TS 24.302. The gateway provides secure transmission of voice and packet traffic through untrusted Wi-Fi channels with IPSec / IKEv2 tunneling and integration with the EPC core through SWu, SWm, SWx, S2b, S6b interfaces.

The solution provides a single monitoring platform for the mobile operator’s operational services — from the IPSec SA (L3 security) level to the KPI of VoWiFi subscriber experience.

• Real-time monitoring — update metrics every 10-15 seconds, directly display the status of IKE SA / Child SA and GTP tunnels in NOC dashboards without delayed aggregation (hereinafter NOC — Network Operation Center, network management center).
• Proactive detection of anomalies — 20+ alarms with automatic escalation in importance. PGW/AAA inaccessibility, increased IKEv2 delays, and an increase in EAP-AKA errors are detected before subscribers notice problems with calls.
• Open integration interfaces — Prometheus, SNMP v2c, Alertmanager webhooks, Grafana support. Integration into the existing NMS/OSS infrastructure without vendor binding.
• Minimum external dependencies at the plugin level — built-in /metrics endpoint in fast-epdg, without Java, without JMX, without external agents.
• Coverage of the entire SWu → S2b stack — IKEv2 (SWu), Diameter SWm/SWx/S6b, GTPv2-C (S2b) and GTP-U data plane — all in one place. The 33 metrics cover control plane and data plane.

All metrics have the prefix epdg_ and are organized in a hierarchy:

epdg_
├── config_*           # Configuration
├── network_*          # Network layer
├── ikev2_*            # SWu (IKEv2/IPSec)
├── gtp_*              # S2b control-plane GTPv2-C
├── gtpu_*             # S2b data-plane GTP-U
├── diameter_*         # SWm/SWx/S6b
├── service_*          # Service KPIs (attach, availability, uptime)
├── session_*          # Session Status (IKE SA, Child SA, GTP, subscribers)
├── app_*              # App Metrics (memory, threads, logs)
└── system_*           # System metrics (CPU, disk, network)

All metrics are exported through a single /metrics endpoint in Prometheus text format. The name follows the rules of Prometheus: epdg_<group>_<name>[_unit], the Counter type has the suffix _total, Histogram is the suffix _seconds/_bytes.

The native /metrics endpoint on port 9817 is built into fast-epdg. The format is standard text format Prometheus v0.0.4 (compatible with OpenMetrics). Aggregation is supported with the central Prometheus operator; remote_write team support for long-term storage in Thanos, Cortex, Grafana Mimir.

47 OID covers the Prometheus metric + 14 trap notifications (with raise/clear pairs according to RFC 3877 ALARM-MIB). Compatible with HP OpenView, IBM Tivoli NetCool, Nokia NetAct, Huawei U2000.

Examples of SNMP requests:

# The entire ePDG tree
snmpwalk -v2c -c public <host>.1.3.6.1.4.1.43823.1
 
# Service availability (Gauge 0..1)
snmpget -v2c -c public <host> .1.3.6.1.4.1.43823.1.1.0

4 JSON dashboard support (35+ panels total):

• ePDG Overview — availability, KPI connections, sessions, state of interfaces
• IKEv2 Details — Messages, Performance, Errors, IKE SA Lifecycle
• GTP Details — GTPv2-C + GTP-U data on PGW nodes
• Diameter Details — Application messages, delays, watchdog

Automatic installation through an API that supports Grafana. Adaptive design for Network Control Center (NOC) status monitors with auto-update every 15 seconds.

Webhook interface for integration with any notification system: Telegram Bot, Slack, PagerDuty Events API v2, OpsGenie, Microsoft Teams. A separate SNMP Trap Sender service converts Alertmanager webhooks to SNMP v2c traps with Enterprise OID.

• Inhibition: Critical alarms automatically suppress Warning for the same component
• Grouping: Alarms are grouped into 'alertname' + 'component' with a 30-second window
• Dead time / Hysteresis: 1 to 10 minutes 'for' prevents false positives
• Trap pairing: raise/clear simultaneous events for compliance with RFC 3877 ALARM-MIB

• Auto Update: 15-second update period
• Adaptive color scheme: green → yellow → red by threshold values
• Drill-down: From Overview to Detail to Component
• Time-range selector: 5 minutes to 30 days of history
• JSON provisioning: Dashboards are automatically deployed

ePDG monitoring is fully integrated into overall packet core monitoring:

The NOC operator sees all EPC components (DPI, SMF, PCEF, FastPCRF, ePDG) in a single Grafana interface, with a single alarm system and notification routing through one Alertmanager.

OSI model:

Operator level:

• On-premise — the plugin runs in the fast-epdg address space, zero resource consumption
• Co-located Prometheus — Prometheus collects metrics from an application running on the same host
• Centralized — a single Prometheus collects from all ePDG nodes

The monitoring section in fast-epdg.conf:

monitoring {
    enabled = yes
    listen_port = 9817
    listen_address = 0.0.0.0
    update_interval = 10
    metrics {
        ikev2 = yes
        gtp = yes
        diameter = yes
        service = yes
        session = yes
        app = yes
        system = yes
    }
}

Each group of metrics can be independently turned on/off without recompilation.