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PGW-C — PDN Gateway (Control Plane)

The PGW-C is the control-plane half of the EPC PDN Gateway. It is the anchor point for every subscriber's data session: it terminates S5/S8 to the SGW‑C, sets up and holds each PDN connection, allocates the UE its IP address from an operator IP pool, and selects and controls the user plane (UPF) over Sx/PFCP. It also runs the session's policy and charging over Diameter — Gx to the PCF/PCRF for policy and QoS, and Gy to the OCS for online charging — and raises CDRs for offline charging. In the 5G core the equivalent function is the SMF. OmniWeb surfaces the PGW‑C's live sessions, IP pools, UPF and Diameter peers, a topology map and session history, and diagnostic tools; longer‑run trends are on the Grafana dashboards reached from the same page.

← Operations Guide

The PGW‑C is a per‑instance element page reached from the sidebar when one runs in the site's inventory, with a fleet view where several are deployed. All traffic goes through the OmniWeb backend proxy to the PGW‑C's API, so it stays behind the single authenticated gateway. The documentation link in the page header (the in‑context help button) opens this page. It is organised into tabs.

Overview​

The PGW-C overview — API status and a summary of active sessions, IP pools, UPF peers and Diameter peers

A single‑screen health read: the API status of the PGW‑C and a summary of its live state — active session count, IP‑pool utilisation, UPF peers and Diameter peers. It is the quickest way to confirm the node is up and carrying sessions.

Sessions​

The Sessions tab listing active PGW sessions by IMSI/MSISDN with their UE IP, APN and bearer state

Every active PGW session, each row keyed by subscriber IMSI and MSISDN with its assigned UE IP and APN. Sessions can be searched by IMSI, UE IP, MSISDN or APN. Opening a session shows its full state — the PDN connection and bearers, the serving SGW and selected UPF, and the live Gx/Gy policy and charging context. A session is editable here: an operator can adjust live state such as the session AMBR (which pushes a new APN‑AMBR down to the UPF) and the requested Gx event triggers that control location‑change reporting. An operator can also delete a session to force‑release a stuck or misbehaving subscriber. Because edits are applied directly to live state, they take effect immediately.

IP Pools​

The IP Pools tab listing each address pool with its size, allocated count and utilisation

The operator IP pools the PGW‑C allocates UE addresses from, each showing its size, allocated count and utilisation. Opening a pool lists the individual allocated addresses. This is where you confirm a pool is not exhausted — an exhausted pool is a common cause of session‑setup failures — and see which subscriber holds a given address.

UPF Peers​

The UPF Peers tab listing the PFCP peers the PGW-C controls, with address and association state

The user‑plane (UPF) peers the PGW‑C controls over Sx/PFCP, each showing its IP address and PFCP association state. Opening a peer shows its details. This is where you confirm the PFCP associations that carry every session's user plane are up.

Diameter​

The Diameter tab listing the PGW-C's Gx and Gy peers with their connection state

The Diameter peers the PGW‑C talks to — the PCF/PCRF over Gx for policy and the OCS over Gy for online charging — each with its hostname and connection state. Opening a peer shows its details. This is where you confirm the policy and charging paths are up when sessions are being rejected or throttled.

History​

The History tab listing session lifecycle events — created, modified, deleted, handover and failed

A searchable, paged log of session lifecycle events — created, modified, deleted, handover and failed. Events can be filtered by type and searched by IMSI, MSISDN, IP address or TEID. This is where you reconstruct what happened to a specific subscriber's session over time, including failures.

Topology​

The Topology tab showing the PGW-C at the centre with its SGW, UPF and Diameter peers around it

A map of the PGW‑C and the neighbours it works with — the SGWs it anchors sessions for, the UPFs it controls, and its Diameter peers — giving a one‑picture view of which signalling and user‑plane neighbours the node is connected to.

UPF Selection​

The UPF Selection tab showing the UPF selection rules, per-UPF health and PCO configuration

The rules that decide which UPF a new session is placed on, together with the current health status of each candidate UPF and the PCO (Protocol Configuration Options) configuration the PGW‑C returns to the UE. This is where you confirm why sessions are landing on a particular UPF and check that all candidates are healthy.

The UE Search tab looking up a subscriber by IMSI, MSISDN or IP address

A direct lookup of a single subscriber by IMSI, MSISDN or IP address, returning that UE's information on the PGW‑C. It is the fastest way to find one subscriber's session without scrolling the full Sessions list.

Charging​

The Charging tab listing each active session's online-charging state — Gy on or off, offline Gz, granted versus used volume and any walled-garden redirect

The live online‑charging (Gy/OCS) state of every active session, each row keyed by IMSI and MSISDN and searchable by either. At a glance each session shows whether Gy online charging is on (with its session id, and the OCS host and realm it talks to), whether offline (Gz) accounting is also running, and whether the OCS has pushed the subscriber into a walled garden redirect. Opening a session expands its full charging detail — the per‑URR granted quotas against the used volume (uplink, downlink and total octets), the final‑unit action the OCS set for when credit runs out, the offline (Gz) counters, and any redirect target. This is how you read a subscriber's live credit‑control state — whether they have credit, how much of their grant they have consumed, and why they may have been throttled or redirected.

CDRs​

The CDRs tab browsing the offline charging records the PGW-C writes, one row per session start, interim and stop event

The offline charging records the PGW‑C writes for billing — one row per session start, interim and stop event, most‑recent first, and filterable by IMSI or MSISDN. Each record carries the subscriber's IMSI, MSISDN and IMEI, the APN and QCI, the charging id that ties a session's records together, the uplink/downlink octets counted for that interval, the S‑GW, PGW and UE IP addresses, and the source file the record was read from. This is where you reconcile a subscriber's data usage against the offline (Gz) accounting the operator bills on, and trace which record file a given session landed in.

Gy Test​

The Gy Test tab — a form that issues a Gy Credit-Control-Request to the OCS and shows the parsed Credit-Control-Answer

An operator tool that issues a Gy Credit‑Control‑Request against the OCS to validate the online‑charging path end to end. You supply an IMSI (and optionally an MSISDN and a requested/used octet count), pick the request type — Initial (CCR‑I) to open a session and request units, Update (CCR‑U) to report usage and ask for more, or Terminate (CCR‑T) to report final usage and close it — and send it; the rating group, Service‑Context‑Id and Auth‑Application‑Id are defaulted by the PGW‑C. The parsed Credit‑Control‑Answer comes back on the same screen. Unlike the other tabs this one does not fetch anything on load — it is a form you submit — and it is the quickest way to prove the OCS is reachable and granting credit when online charging is misbehaving.

P-CSCF Monitor​

The P-CSCF Monitor tab showing the P-CSCF discovery monitor status and metrics

The status and metrics of the P‑CSCF discovery monitor — the PGW‑C returns a P‑CSCF address to VoLTE devices during PDN setup, and this tab confirms that discovery is healthy so IMS registration can proceed.

Logs​

The Logs tab tails the PGW‑C's live log output for troubleshooting a single node — session‑setup failures, PFCP and Diameter errors — without leaving OmniWeb.

Monitoring​

Session‑count trends, throughput and other time‑series for the PGW‑C are presented as Grafana dashboards, reached from the element page — OmniWeb does not duplicate those charts natively.

  • The SGW‑C is the control peer over S5/S8; it anchors the access‑side bearers the PGW‑C connects to the PDN.
  • The UPF is the user plane the PGW‑C selects and controls over Sx/PFCP.
  • The PCF/PCRF provides policy and QoS over Gx.
  • The CHF/OCS performs online charging over Gy; the PGW‑C also raises CDRs for offline charging.
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