3GPP MCX InterWorking Function (IWF)

IWF for LMR (APCO P25, TETRA, DMR, RoIP, Analog)

Etherstack has developed and deployed the world’s first standards based LMR-IWF solution for deployment with 3GPP compliant MCX solutions, such as those used by AT&T FirstNet.

Etherstack’s high performance LMR-IWF is designed to scale from national, carrier deployed, geo-redundant, multi-agency deployments all the way down to single agency enterprise deployments.

The Etherstack LMR-IWF supports the following wireline interface protocols:

  • APCO P25 ISSI (inter RF-sub system interface), TIA
  • APCO P25 CSSI (console sub system interface), TIA
  • APCO P25 DFSI (digital fixed station interface), TIA
  • DMR AIS (application interface specification), ETSI
  • Multiple RoIP flavors (SIP & RTP based radio over IP)
  • Analog and P25 AFSI (including CTCSS/CDCSS, SELCAL), requires Etherstack AOR unit
  • Open Standard and Proprietary TETRA interfaces on request
  • Other protocols on demand

Etherstack’s carrier grade solution allows support for multiple LMR protocols from the one LMR-IWF solution.

Etherstack understands PMR/LMR Protocols

For over two decades, Etherstack has licensed TETRA, APCO P25 and DMR protocol stacks as well as IP softswitching solutions to over twenty wireless equipment manufacturers globally. These include mobile and base station/repeater manufacturers, as well as console and digital voice recording vendors.

We have licensed all the building blocks from cryptographic implementations, vocoders and OTAR (over-the-air-rekeying) technologies including US NIST certified crypto modules, Key Management Facilities and sigint solutions.

The company contributes to standards development in both narrowband and broadband standardisation efforts.

As the world’s leading licensor of PMR/LMR protocols and LMR gateway technologies to other manufacturers, we were the obvious choice for solving the LMR-IWF task for the AT&T FirstNet network.

Transcoding & Transcrypting Functions

Etherstack’s LMR-IWF consists of three main components. The LMR interface side, the core InterWorking Function element and the MCPTT interface side.

Inside the IWF element, narrowband voice frames are decrypted using the selected talkgroup algorithm and keysets, then transcoded from PMR/LMR vocoders such as ACELP, IMBE and AMBE to 3GPP MCPTT AMR-WB, re-encrypted and passed to the MCPTT interface side to pass the media to the MCX switch for distribution. The process works similarly in reverse.

Etherstack has multiple security architectures available for the transcription function to satisfy the needs of different national security requirements, at the enterprise, carrier and government level. Get in touch with us and we will tell you how.

High Availability, Fault Tolerant

Etherstack has been building and deploying high availability fault tolerant PTT softswitching technology for over 15 years.

The Etherstack LMR-IWF can be deployed in carrier data centres and supports geo-redundancy. At the enterprise level, the LMR-IWF can be deployed on COTS telco grade platforms such as Dell servers in active/standby HA redundancy including geographically isolated disaster recovery nodes, or on clusters in an enterprise data center.

Always Innovating. Always Leading

Etherstack undertook the world’s first native APCO P25 calls over LTE at Bell Labs in New Jersey in March 2011 utilising the TIA ISSI network interface to link to an APCO P25 core network.

In 2012, at Old Street in London, Etherstack demonstrated the first PTT over Cellular calls with EE.

Fast forward a decade to today, and Etherstack are deploying the LMR-IWF element with global partner Samsung for AT&T’s FirstNet offering with AT&T’s network.

Talk To Us

Whether you are in Boise, Idaho or Munich, Germany or Tokyo, Japan, just reach out to your nearest Etherstack office and let us tell you more about how we can help.