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While the variable message format (VMF) is typically thought of as a ground force tactical data link (TDL), VMF will support whatever environment is desired.

This is important, especially used in combination with the Link 16 TDL, a communications system that delivers crucial exchange of situational awareness among U.S., NATO and Coalition forces inside the chaos of a battlespace, which includes ground, air and sea communications.

VMF is well suited for  communications bandwidth constrained situations when Combat  Net Radio (CNR) networks are deployed and used. VMF and the Joint Range Extension Applications Protocol (JREAP) enable the exchange of voice, mission and tactical data and imagery by connecting to a network of various participant nodes, platforms and units, both vertically and horizontally.

VMF is widely used because it has the ability to operate over a wide range of RF bearers (radio frequency channels) such as UHF, VHF, HF and SATCOM – whatever the situation requires. However, in reality almost all of VMF is passed along using the Single Channel Ground and Airborne Radio System (SINCGARS) Combat Net Radios (CNR), the Ultra High Frequency HAVEQUICK (a frequency hopping system used as an anti-jamming communication system) or the Enhanced Position Location Reporting System (EPLRS).

Another VMF communication characteristic: VMF systems use Ethernet principles, a family of computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN).

VMF operations are organized into subnetworks (LANs) of up to 12 units. The LANs may be connected together via WAN using IP (Internet Protocol). Messaging works like this:

  • PC1 sends data – all others listen and receive. PCs only process data addressed to them or to all.
  • PC2 listens for gap – net not busy – transmits data. A unit will only process information addressed to it.

As a communication protocol, VMF follows a system of rules that permit two or more parties in a communications system to transmit information. The protocol defines the rules syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both.

VMF is one of the J-Series family of Tactical Data Links (TDLs) to which most allied nations are trying to assimilate. The J-Series family includes Link 16, Link 22 and IBS (Integrated Broadcast Service).

VMF, as typically used, is controlled by 3 documents:

  • MIL-STD-6017 (VMF) – General rules and KSeries message catalogue
  • MIL-STD-2045-47001 – Message header, mandatory for use with VMF messages
  • MIL-STD-188-220 – Combat Net Radio (CNR) protocols VMF uses K-Series messages that are defined in MIL-STD-6017 (VMF).

The messages are arranged in a set of 11 Functional Areas (FA) such as Fire Support and Land Combat Operations, but this is only done for convenience rather than use protocols such as are found in Link 16 NPGs.

There are well over 100 messages and the catalogue grows continually.

Variable Message Format Training

Tonex offers a 4-day Variable Message Format (VMF) Training Bootcamp. Participants can expect to gleam information from a variety of topics, including:

  • Key concepts behind Variable Message Format (VMF)
  • VMF use cases
  • VMF Operations and Network Management
  • The Variable Message Format Protocol
  • Schema of the Application Header of a VMF message
  • Encapsulation process of user data into a VMF message
  • Communication protocols that are transmission media independent

Who Can Benefit?

  • TDL operators
  • TDL certification and testing professionals
  • Engineers and technicians
  • Analysts
  • Other military and defense professionals

Why Tonex?

–Reasonably priced classes taught by the best trainers is the reason all kinds of organizations from Fortune 500 companies to government’s most important agencies return for updates in courses and hands-on workshops.

–So far we have helped over 20,000 developers in over 50 countries stay up to date with cutting edge information from our training categories.

–Ratings tabulated from student feedback post-course evaluations show an amazing 98 percent satisfaction score.

Contact us for more information, questions, comments.


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