Diameter Load Balancer

DMT-LB is a Diameter router that sits between Diameter originators and a pool of Diameter peers, terminating sessions over both TCP and SCTP and routing each request to the right destination by realm — consolidating what would otherwise be a full mesh of point-to-point Diameter peer connections into a single administered routing point. Beyond routing, DMT-LB can rewrite AVPs in flight, adding, modifying or removing attributes on a request before it reaches its destination.

Features & Benefits

Multi-peer Diameter router over TCP or SCTP

DMT-LB terminates Diameter connections from and to any number of peers, over either TCP or SCTP transport, and exposes full peer lifecycle management — add, remove, start, stop — over REST.

Routing by realm or by Redirect-Host AVP

Requests are routed by exact or pattern-matched Destination-Realm, with a wildcard fallback, or by the Redirect-Host AVP when a peer indicates one — one routing layer instead of realm configuration duplicated on every originator.

AVP manipulation on inbound requests

Match conditions (equals, contains, regex, starts/ends with) drive add, modify or remove operations on AVPs — including nested grouped AVPs — in requests before they're forwarded, hot-reloaded from a rules file without a restart.

Broad Diameter application coverage out of the box

The shipped dictionary covers Diameter base, NASREQ, base accounting, credit control (RFC 4006), and 3GPP Rf/Ro, Cx/Dx, Sh, Gx, Rx, Gq, S6a and S13/S13' — the applications most Diameter peers in a mobile core actually speak.

Spread and fail over requests within one Diameter application

One realm, one application, several equivalent peers behind it

Deployed in front of a single Diameter application — for example Ro toward the OCS — DMT-LB terminates every originator that speaks that application and resolves the destination realm to a pool of equivalent peers rather than one fixed instance. Requests are spread across whichever peers currently match that realm, so adding OCS capacity or taking one instance out for maintenance is a peer-table change, not a re-point of every originator.

This mode suits an interface where the destination is really a cluster — several OCS, PCRF or HSS instances behind the same realm — and DMT-LB's job is distribution and failover within that one application, not routing between different applications.

DMT-LB single application mode: AAA-AEF, other AFs/AEFs and PGW/GGSN all reach DMT-LB, which spreads and fails over Diameter Ro requests across a pool of equivalent OCS peers; an OSS/NMS administers peers, realms and AVP rules over a REST Admin API. Every element sits inside the operator domain.

Consolidate several Diameter applications onto one router

Several realms, several applications, one router between them

DMT-LB multi application mode: AAA-AEF, other AFs/AEFs and PGW/GGSN reach DMT-LB, which routes each request by realm to the right application's peer — OCS over Ro, PCRF over Gx, HSS over Cx/Sh/S6a; an OSS/NMS administers peers, realms and AVP rules over a REST Admin API. Every element sits inside the operator domain.

Deployed between Diameter-originating elements (AAA-AEF, MTC-AEF, other AFs/AEFs, or PGWs/GGSNs) and the distinct Diameter peers behind each application they need to reach — OCS over Ro, PCRF over Gx, HSS over Cx/Sh/S6a — DMT-LB terminates every connection once and resolves each request to the right application's peer by realm, administered and monitored over REST.

Technical specifications

REST Admin API

Peers, realms, applications, AVP rules

Slicce internal

Diameter Base

IETF RFC 6733

NASREQ

IETF RFC 4005

Credit Control

IETF RFC 4006

3GPP Applications

Rf / Ro / Cx / Dx / Sh / Gx / Rx / Gq / S6a / S13

3GPP TS 32.299 / 29.212 / 29.228 / 29.328 / 29.272 / 29.336

Transport

TCP or SCTP

IETF RFC 4960

Architecture

Diameter agent/relay role per IETF RFC 6733 §2.8 (no single dedicated architecture document)