- A diameter AAA server handles Authentication, Authorization, and Accounting using the Diameter Base Protocol (RFC 6733), running over TCP or SCTP – providing reliable, failure-aware transport that RADIUS over UDP cannot match at carrier transaction volumes.
- In 4G LTE, Diameter is mandatory on S6a (subscriber authentication), Gx (policy), Gy (online charging), SWm, and STa – defined in 3GPP specifications, not operator configuration choices.
- In 5G SA, core 3GPP authentication migrates to AUSF/UDM over HTTP/2; Diameter persists for non-3GPP access (Wi-Fi calling, WLAN offload) and for every operator running 5G Non-Standalone (NSA) with an LTE anchor core.
- Alepo’s Diameter AAA runs across operator networks globally, engineered for carrier-scale transaction volumes at low latency and 99.999% availability – fewer than six minutes of unplanned downtime per year.
- Alepo runs carrier-grade Diameter AAA on Kubernetes (GCP, AWS, Azure, or on-premise) in active-active geo-redundant configuration, with session state externalized so it survives container restarts.
Every time a subscriber initiates a data session on an LTE or 5G network, the diameter AAA server, the node that handles Authentication, Authorization, and Accounting (AAA) – is the system adjudicating that request before the first packet is forwarded. It validates identity, applies contracted policy, and opens an accounting session for every byte that follows. A failure at that point is not a background event; it is a subscriber who cannot connect, a Quality of Service (QoS) class that defaults to best-effort, or a charging gap that takes a billing audit to close.
In 2026, the architectural stakes have sharpened. 5G Standalone (SA) rollouts force operators to reconcile Diameter-based LTE authentication with HTTP/2 service-based interfaces in the 5G core. Operators still on legacy platforms such as Cisco CPAR face end-of-support pressure with no vendor migration path. And cloud-native deployments surface a session-state challenge most AAA documentation papers over: how to maintain long-lived Diameter sessions across container restarts without triggering subscriber re-authentication.
This guide covers what a diameter AAA server is and how it operates in carrier networks, which Diameter interfaces are mandatory in 4G and 5G, how Diameter and RADIUS compare at the protocol level, deployment and high-availability architecture, and how Alepo addresses each of these in production.
What Is a Diameter AAA Server?
Authentication, Authorization, and Accounting are three separate policy operations executed in sequence for every subscriber session. Authentication confirms identity. Authorization applies service entitlements – QoS class, rate limits, service restrictions. Accounting records usage for billing and compliance. The system that executes all three at carrier scale is the AAA server. For 4G LTE and most 5G deployments, that server speaks Diameter.
Definition and Core Function
A diameter AAA server is a network policy-enforcement node that authenticates subscriber identities, authorizes service access based on subscriber profile and operator policy, and accounts for session usage in real time – operating over the Diameter Base Protocol as defined in RFC 6733.
Diameter succeeded RADIUS (RFC 2865) to address the reliability and extensibility limits RADIUS exposes at carrier scale. Where RADIUS runs over UDP with no guaranteed delivery and a 255-attribute type limit before vendor-specific extensions are required, Diameter uses TCP or SCTP – connection-oriented transport with native error detection and a 32-bit Attribute-Value Pair (AVP) code space with grouped attribute support. A Diameter AAA server is architecturally distinct from a Diameter Routing Agent (DRA): the AAA server holds subscriber policy state and makes policy decisions; the DRA routes Diameter messages between network nodes without making decisions. Conflating these two functions is a common architectural error in Diameter RFP evaluations.
How It Works in Carrier Networks
When a subscriber attaches to an LTE network, the Mobility Management Entity (MME) sends an Authentication-Information-Request (AIR) to the AAA server over S6a, carrying the subscriber’s IMSI. The server generates authentication vectors – RAND, AUTN, XRES – and returns them in the Authentication-Information-Answer (AIA). The MME challenges the device and validates the response before allowing session establishment.
Once authenticated, the Policy and Charging Enforcement Function (PCEF) initiates a Gx session with the Policy and Charging Rules Function (PCRF) to retrieve QoS policy rules encoded as Charging-Rule-Install AVPs – specifying QoS-Class-Identifier (QCI), Allocation-and-Retention-Priority (ARP), and bearer bitrates. For online charging, the PCEF opens a Gy session with the Online Charging System (OCS) under the Diameter Credit Control Application to reserve quota before the session carries traffic. Every attribute in these exchanges is encoded as a Diameter AVP – structured data in grouped hierarchies that map directly to 3GPP policy constructs without the workaround layer RADIUS requires.
Why It Matters for CSPs Today
Three operational consequences follow from whether a Communications Service Provider’s (CSP’s) diameter AAA server is carrier-grade or not.
Revenue integrity: if the Gy interface fails to reserve credit before session establishment, subscribers consume services without being charged – a systematic billing gap that requires post-session audit to close.
Subscriber experience: a delayed Gx session leaves the PCEF applying default policy instead of the contracted QoS class; a business subscriber on a guaranteed-bitrate SLA gets best-effort throughput, and the impact shows up in SLA penalty clauses, not AAA logs.
Regulatory compliance: operators in regulated markets carry lawful-intercept and data-retention obligations tied to the accounting function; an AAA server that cannot produce complete, timestamped Charging Data Records (CDRs) in the required format creates regulatory exposure independent of the rest of the network.
Diameter Interfaces in 4G: Gx, Gy, Gz, S6a
In a production 4G network, Diameter runs on several interfaces simultaneously, each carrying a distinct application. Designing AAA architecture without a precise interface map is how operators end up with policy gaps and charging inconsistencies that are difficult to attribute.
Diameter Protocol Mechanics
Diameter is a peer-to-peer protocol, not client-server. Any Diameter node can initiate messages to any peer – the PCEF sends Credit-Control-Requests (CCR) to the PCRF on Gx; the MME sends AIRs to the AAA server on S6a; the AAA server sends Re-Authorization-Requests (RAR) to the PCEF when policy needs to be pushed mid-session without a re-authentication cycle.
Before any application messages flow, Diameter peers exchange Capabilities-Exchange-Request (CER) and Capabilities-Exchange-Answer (CEA) messages, declaring which Diameter applications each peer supports. This prevents the class of silent failures common in RADIUS deployments, where a misconfigured Network Access Server (NAS) sends unsupported attribute types and receives rejections with no diagnostic information. Application-specific command sets extend the base protocol without modifying it.
Diameter Interfaces at a Glance
| Interface | Between | Primary Function |
|---|---|---|
| S6a | MME ↔ HSS/AAA | Subscriber authentication vectors and profile |
| Gx | PCEF ↔ PCRF | QoS policy and charging rule installation |
| Gy | PCEF ↔ OCS | Online charging / credit reservation |
| Gz | PCEF ↔ OFCS | Offline CDR delivery |
| S6b | ePDG ↔ AAA | Non-3GPP authorization and IPv6 prefix |
| SWm | ePDG ↔ AAA | EAP-based untrusted WLAN authentication |
| STa | TWAN ↔ AAA | Trusted WLAN access authentication |
The Gx interface carries the bulk of policy complexity. A single subscriber session typically has multiple simultaneous charging rules active: one for the default bearer, one for a dedicated VoLTE bearer (QCI 1), and potentially one for a sponsored data service with separate accounting – each as a Charging-Rule-Install AVP containing nested QoS-Information AVPs.
SWm is the interface operators encounter when deploying Wi-Fi calling. When a subscriber connects over untrusted WLAN and triggers IMS voice, the evolved Packet Data Gateway (ePDG) authenticates over SWm to the AAA server using EAP-AKA or EAP-AKA’. This is a completely separate authentication path from S6a – requiring its own session-management capacity and high-availability path. Operators who size AAA infrastructure only against S6a volume consistently undercount actual load when Wi-Fi calling is in service.
Diameter vs RADIUS: When to Use Each
If a network includes an LTE RAN, IMS/VoLTE, or any non-3GPP offload path, Diameter is not a choice on those interfaces. The 3GPP specifications define it as mandatory on S6a, Gx, Gy, SWm, S6b, and STa. Using RADIUS here requires a translation proxy – an additional failure point that must be maintained across every 3GPP release that modifies AVP definitions.
If a network authenticates fixed-broadband subscribers over PPPoE or IPoE to a BRAS, or operates an Internet Service Provider (ISP) access layer without 3GPP interface requirements, RADIUS is the correct choice. The NAS vendor support for fixed access is broader on RADIUS, with mature operational tooling.
Most carrier networks require both simultaneously. An AAA platform that handles both protocols natively on a single subscriber database eliminates the profile-drift risk of running synchronized separate systems.
Diameter in 5G: Where It Still Applies
The 5G Standalone core replaces Diameter with HTTP/2-based Service-Based Interfaces for authentication within the 5G core. This is a real architectural change, and it does not eliminate Diameter from a production operator network.
5G SA Architecture Requirements for AAA
Within 5G SA, authentication for 3GPP access migrates to the Authentication Server Function (AUSF) using HTTP/2 and JSON. The Access and Mobility Management Function (AMF) replaces the MME; the Unified Data Management (UDM) function replaces the Home Subscriber Server (HSS). Diameter does not run between AMF and AUSF, or between AUSF and UDM.
Two network categories remain Diameter-dependent in 5G SA. First: operators running 5G NSA, where New Radio carries the data plane but an LTE anchor and Evolved Packet Core (EPC) handle signalling – the EPC runs S6a Diameter to an HSS or AAA server. Most deployed 5G subscriber bases as of 2026 are NSA. Second: non-3GPP access – Wi-Fi calling via untrusted WLAN, trusted WLAN, and fixed wireline – continues to use Diameter AAA even in full 5G SA networks. Decommissioning Diameter AAA before these paths are independently migrated removes active authentication for Wi-Fi subscribers.
AUSF, UDM and Legacy AAA Coexistence
In 5G SA, the AUSF handles 5G-AKA and EAP-AKA’ for NR-attached subscribers, interfacing with the UDM for credential retrieval. Neither function speaks Diameter to the 5G core. The coexistence challenge is that most operators running 5G SA also maintain an LTE RAN and EPC for coverage continuity, MVNO hosting, and IoT devices that are not 5G-capable – that EPC still terminates S6a Diameter. Alepo’s platform supports this dual-path operation: the same subscriber record is accessible to both Diameter AAA (for LTE and non-3GPP paths) and 5G core authentication functions, with integration to HSS and UDM via Diameter S6b and SWx, without subscriber-profile duplication across separate databases.
Migration Path from 4G to 5G SA
Phased migration is the only operationally safe approach.
- Audit the subscriber database — export all profiles, RADIUS attributes, and Diameter AVP extensions, including vendor-specific AVPs, and map each to the target UDM data model before migration begins.
- Map S6a interface dependencies — identify every MME terminating S6a sessions to the AAA server and document concurrent session volumes per MME before any traffic is migrated.
- Deploy and validate AUSF and UDM in staging — validate 5G-AKA flows against a test SIM batch before production traffic reaches the new path.
- Maintain Diameter coexistence throughout — the Diameter AAA stays live for LTE and non-3GPP paths. S6a decommission does not happen until every subscriber-carrying MME has been migrated to an AMF and LTE coverage independently confirmed.
- Migrate traffic by subscriber cohort — move by MME, region, or IMSI range with rollback maintained at each step. Parallel-run validation confirms consistent authentication behaviour before each cohort cutover.
- Keep Diameter AAA for non-3GPP access post-core-migration — SWm and STa remain Diameter even after full 5G SA core migration. Plan Diameter decommission only when non-3GPP access has fully migrated with AUSF authentication validated across all device types.
Diameter vs RADIUS: Which Protocol?
The choice between Diameter and RADIUS is not an evaluation question for most carrier networks — the 3GPP specifications resolve it per interface. It is a live question for operators evaluating platforms for converged fixed-mobile networks, or for architects who inherited a RADIUS-only deployment and need to understand the migration scope.
| Criterion | RADIUS (RFC 2865) | Diameter (RFC 6733) |
|---|---|---|
| Transport | UDP — no guaranteed delivery | TCP / SCTP — connection-oriented, reliable |
| Error handling | Application-level retry only | Native transport-level error codes + retransmission |
| Message model | Client-server — NAS always initiates | Peer-to-peer — any node can initiate |
| Attribute format | 8-bit type; 255 max before VSAs | 32-bit AVP code; grouped AVP support |
| Failover | Manual retry in NAS | Native Diameter Watchdog keepalive |
| Security | Shared secret + MD5 (deprecated) | TLS at transport layer; native IPsec |
| 3GPP 4G/5G requirement | Fixed broadband, WISP, legacy NAS | S6a, Gx, Gy, SWm, S6b, STa — mandatory |
Feature-by-Feature Comparison
The transport-layer difference manifests first in production. RADIUS over UDP means the NAS retransmits unanswered requests after a configurable timeout – typically three to five seconds. Under sustained load, missed UDP responses generate retransmission bursts that amplify AAA server load at exactly the moment capacity is most constrained. Diameter’s TCP/SCTP transport detects connection failure via the Diameter Watchdog mechanism, triggering application-layer failover before the NAS retransmits.
The AVP extensibility difference becomes significant in complex policy environments. RADIUS uses an 8-bit type field – 255 possible standard codes before vendor-specific extensions require custom parsing at each NAS. Diameter’s 32-bit AVP code space with grouped attributes carries structured policy data natively: a Charging-Rule-Install AVP carries nested QoS-Information and Flow-Information AVPs in one message, with no VSA layer.
Performance and Availability
Alepo’s Diameter AAA platform is engineered for carrier-scale authentication transaction volumes at low latency in production deployments. At 99.999% availability, that is fewer than six minutes of unplanned downtime per year – the availability class required for a network function on the authentication path. Specific throughput benchmarks are validated against each operator’s peak authentication and accounting profile during PoC.
Which Should You Choose?
If a network operates an LTE RAN, 5G NSA, IMS/VoLTE, or non-3GPP offload: choose Diameter for the 3GPP-specified interfaces. S6a, Gx, Gy, SWm, STa, and S6b are defined by 3GPP – not configurable. A RADIUS-based approach on these interfaces requires a translation proxy that must be maintained across 3GPP releases.
If a network authenticates fixed-broadband CPE over PPPoE or IPoE without 3GPP interface requirements: choose RADIUS. The fixed-access NAS vendor support is broader for RADIUS and the operational tooling is mature.
If a network is converged – fixed broadband and mobile together: choose a platform that handles both protocols natively. Separate RADIUS and Diameter servers with synchronized subscriber profiles introduce profile-drift risk operators eventually want to eliminate.
Deployment: Architecture Considerations
A Diameter AAA deployment is a set of integrated components whose architecture determines the failure modes the operator manages for the next five to ten years. Component boundaries and integration patterns set at deployment are the ones that require core-network changes to fix later.
Core Architectural Components
A production Diameter AAA deployment has four functional layers. The Diameter signalling layer terminates and processes AAA messages and scales horizontally as authentication load increases. The subscriber data layer holds subscriber profiles and active session state – the stateful component that requires careful handling in containerized deployments. The policy engine evaluates incoming requests against operator rules and subscriber attributes. The charging interface layer bridges to the OCS for online credit control (Gy) and to the offline charging system for CDR delivery (Gz).
The DRA sits outside the AAA server. It accepts Diameter connections from MMEs, PCEFs, and ePDGs, and routes requests to AAA server instances based on load and realm-routing rules. Operators who connect network elements directly to a fixed AAA endpoint without a DRA lose the ability to scale AAA horizontally without reconfiguring every connecting network function.
Data Flow and Integration Points
- Subscriber attach. The MME sends an AIR to the AAA server over S6a with the subscriber’s IMSI. The server generates authentication vectors (RAND, AUTN, XRES, KASME) and returns them in the AIA. The MME challenges the device, validates RES against XRES, and confirms authentication.
- Profile delivery. The MME sends an Update-Location-Request (ULR) over S6a. The AAA server returns the subscriber’s profile – QoS defaults, APN configurations, roaming permissions – in the Update-Location-Answer (ULA).
- Policy and charging session initiation. As the P-GW establishes the default bearer, the PCEF sends a CCR-Initial over Gx. The PCRF returns Charging-Rule-Install AVPs. For prepaid subscribers, the PCEF sends a CCR-Initial over Gy; the OCS grants a quota before data flows.
- Session accounting. The AAA server generates session start, interim, and stop records for billing, lawful intercept, and compliance reporting.
High Availability and Redundancy Design
Diameter’s Watchdog mechanism defines the Device-Watchdog-Request (DWR) / Device-Watchdog-Answer (DWA) keepalive. When a Diameter peer fails to respond to DWR within the configured timeout, the sending peer declares that connection unavailable and fails over to an alternate peer without waiting for TCP timeout. This is a protocol-level mechanism, not a vendor feature.
At the architecture level, active-active redundancy means multiple AAA server instances serving traffic simultaneously with session state synchronized across instances. A failed node does not require subscriber re-authentication – surviving instances hold the session state and continue serving active sessions. Alepo deploys in active-active geo-redundant pairs across its production carrier deployments.
High Availability for Diameter AAA
High availability for a stateful protocol like Diameter requires solving two problems independently: transport-level connection resilience and session-level state continuity. Most vendor documentation addresses the first clearly and gives vague answers on the second. Session-state continuity is what causes production incidents.
Active-Active vs Active-Standby Clustering
In an active-standby configuration, one AAA node handles all live traffic while a warm standby waits to take over after a configured number of missed DWR responses. Subscribers with in-flight sessions at failover must re-authenticate – the standby does not hold session state from the primary. For a carrier network with tens of thousands of concurrent sessions, even a brief re-authentication wave generates measurable RAN load and subscriber-visible service interruption.
In an active-active configuration, multiple AAA nodes share traffic simultaneously and maintain a synchronized view of subscriber session state. If one node fails, in-flight sessions continue on surviving nodes without re-authentication. The trade-off is state-synchronization overhead on every session write – the engineering objective is to minimize that overhead while maintaining consistency guarantees that prevent split-brain state under concurrent updates.
Session State Replication Under Failover
For a Diameter AAA server, session state includes the subscriber IMSI and authenticated identity, the allocated IP address, active Charging-Rule-Install AVPs from the PCRF, the current OCS-granted quota, session timestamps for CDR generation, and vendor-specific session attributes – roaming status, MVNO identifiers, lawful-intercept flags.
In containerized deployments, session state introduces a constraint that stateless HTTP services do not face: a container that holds session state locally loses it on restart. Subscribers mid-session on that container must re-authenticate unless state is externalized or replicated. This is the specific failure mode operators discover in cloud-native AAA deployments when container restart policies are misconfigured or session externalization is not implemented. Alepo’s platform covers session persistence and duplicate detection natively, with session state externalized to a replicated data layer.
Kubernetes-Native HA for Diameter AAA
Running a stateful protocol like Diameter on Kubernetes requires decisions that do not apply to stateless APIs. The protocol-level requirement is consistent regardless of implementation: a Diameter peer connection identified by an origin host and origin realm must survive the restart of the software instance handling it, with session state intact. Diameter’s CER/CEA handshake for new peer connections adds initialization time that must be accounted for in container readiness probes – a container that has not completed capability exchange with its peers is not ready to receive production traffic even if the process is healthy.
Alepo runs carrier-grade Diameter AAA on Kubernetes – on GCP, AWS, Azure, or on-premise K8s – in active-active geo-redundant configuration, with session state externalized so that session continuity is maintained across container restarts. This is a production deployment model carrying live subscriber authentication traffic, not a reference architecture or a PoC.
Alepo Diameter AAA
Alepo’s Diameter AAA platform runs in production across operator networks globally, with 10+ AAA deployment references worldwide – including deployments serving 200,000+ concurrent subscribers and subscriber bases into the millions. Alepo has migrated operators from legacy AAA platforms, including Cisco CPAR and open-source DIY deployments, drawing on long-standing telecom AAA delivery experience.
Download Alepo AAA Data Sheet here
Key Technical Differentiators
- Native Diameter and RADIUS on a single platform.
Alepo terminates RADIUS, Diameter, and TACACS+ on one platform – a single subscriber database, a single policy engine, no translation proxy. Operators running converged fixed-mobile networks manage a unified subscriber record, eliminating the profile-drift risk of synchronized separate AAA servers.
- Broad 3GPP Diameter interface coverage.
Alepo supports S6a, S6b, SWx, SWm, Sh, Gx, Gy, Sd, STa, SWa, and SWd – the 4G interface set plus the non-3GPP interfaces that remain Diameter in 5G SA deployments. Integration with HSS and UDM is via Diameter S6b and SWx.
- Carrier-grade throughput. Active-active geo-redundant.
Engineered for carrier-scale transaction volumes at low latency. At 99.999% availability, fewer than six minutes of unplanned downtime per year. All deployment models – Kubernetes, VM, bare-metal – run in active-active geo-redundant pairs.
- AI Agent for AAA — a security and operations control plane.
Alepo AAA ships with an AI Agent layer that turns RADIUS, Diameter, and TACACS+ logs into a real-time security and operational control plane: anomaly detection on unauthorized access, brute-force and credential-stuffing detection, DDoS prediction, and SIEM/firewall trigger integration. This is part of the AAA stack, not a separate product to integrate.
Deployment and Integration Approach
Alepo supports deployment models matched to operator infrastructure maturity: containerized on Kubernetes (GCP, AWS, Azure, on-premise K8s) – active-active geo-redundant, standard for new deployments; virtualized on VMware, OpenStack, or hyperscaler IaaS; bare-metal for highest-throughput, latency-sensitive packet-core deployments; private cloud (AWS/Azure/GCP) for cloud-first operators in data-residency-controlled regions; on-premises for regulated markets or data-sovereignty mandates; and a fully managed service for operators that want Alepo to run and operate the AAA.
Integration sequence for LTE deployments: S6a to the MME is validated first, followed by Gx to the PCEF/PCRF, then Gy to the OCS. Alepo provides integration test harnesses for each interface, allowing operators to validate Diameter message flows against a staging AAA instance before production traffic is routed.
Proven in Production
Alepo’s Diameter AAA runs in production for Tier-1 and Tier-2 operators across broadband, mobile, and Wi-Fi calling authentication, spanning the SWm and STa interfaces for non-3GPP access. Across its migration projects from Cisco CPAR and other legacy platforms, Alepo executes a consistent process: subscriber-database export and attribute mapping, parallel-run validation with production traffic split between old and new systems, and cohort cutover with rollback maintained at each stage.
Frequently Asked Questions
What is a diameter AAA server and why does it matter for telecom operators?
A diameter AAA server is the network node that authenticates subscriber identities, authorizes service access, and accounts for session usage using the Diameter Base Protocol (RFC 6733). It matters because every subscriber session on a 4G or 5G network depends on it: authentication failures block service, authorization errors apply incorrect QoS, and accounting gaps create billing leaks that require audit to recover. In a 3GPP network, there is no functional substitute for a carrier-grade AAA server on the S6a, Gx, and Gy interfaces.
What is the Diameter protocol and how does it differ from RADIUS?
Diameter (RFC 6733) is the carrier-grade successor to RADIUS (RFC 2865). Diameter runs over TCP or SCTP – providing reliable, connection-oriented transport with native failover via the Diameter Watchdog mechanism – while RADIUS runs over UDP with no guaranteed delivery. Diameter uses 32-bit AVP codes with grouped attribute support; RADIUS uses 8-bit attribute types capped at 255 entries before vendor-specific extensions. For 3GPP interfaces in 4G and 5G networks, Diameter is mandatory.
Which Diameter interfaces does an AAA server need for 4G and 5G?
For 4G LTE: S6a (subscriber authentication and profile), Gx (policy rules), Gy (online charging), SWm (Wi-Fi calling authentication), STa (trusted WLAN), and S6b (authorization and IPv6 assignment). For 5G SA, non-3GPP access continues to use SWm and STa via Diameter; core 3GPP authentication migrates to AUSF and UDM over HTTP/2. Operators running 5G NSA require the full 4G Diameter interface set.
Can a single AAA server support both RADIUS and Diameter?
Yes – if the platform is designed for it. Alepo handles RADIUS, Diameter, and TACACS+ natively on a single subscriber database and policy engine, without a translation proxy between protocols. Operators running both fixed broadband (RADIUS/PPPoE) and mobile (Diameter/LTE) manage a unified subscriber record without cross-protocol synchronization tooling. Not all AAA vendors support this natively; some require separate instances with periodic database replication, which introduces profile-drift risk.
How long does it take to deploy a diameter AAA server?
Deployment timeline depends on network topology and migration scope. A greenfield Diameter AAA deployment with no subscriber migration typically validates S6a integration and reaches production readiness in weeks. A migration from Cisco CPAR or another legacy AAA – including subscriber-database export, attribute mapping, parallel-run validation, and cohort cutover – is a longer engagement that scales with subscriber-base size, MME count, and access-layer complexity.
Conclusion
A diameter AAA server is the authentication, authorization, and accounting enforcement layer every 4G and 5G network depends on – running Diameter on 3GPP-defined interfaces (S6a, Gx, Gy, SWm, STa) and coexisting with RADIUS for fixed and legacy access. The 5G SA transition changes where Diameter applies, not whether it applies: for NSA networks and any network with non-3GPP access, Diameter decommission is a late-stage outcome reached only after specific paths are independently migrated, not a 5G migration prerequisite.
High availability in a cloud-native Diameter deployment requires solving stateful session persistence across container restarts – a problem most vendors describe generically. Alepo runs Diameter AAA across operator networks worldwide, with production Kubernetes deployments running active-active geo-redundant and session continuity maintained across container restarts.
If this guide has given you the protocol-level grounding to evaluate your Diameter AAA options, the next step is seeing how Alepo’s platform applies to your specific interface requirements and migration timeline.
Want to see how Alepo AAA Server works for 4G and 5G? Book a demo now.
