Stanag 4406 Annex E gateway

With military forces deployed internationally in coalition environments, appropriate communication methods are paramount. Messaging systems are a vital part of the infrastructure for the modern military, but rely on two-way communication and are therefore unsuitable for environments where “radio silence” is needed. Boldon James has developed Tactical Messenger, for deployment with Microsoft Exchange, to provide a reliable multicast protocol in a connectionless oriented network. The solution provides data compression, manages message priority and precedence, and can intelligently manage message queues, interrupting low priority messages to ensure delivery of the most important first.
Tactical Messenger supports NATO STANAG 4406 Edition 2 Annex E and ACP142 (P_MUL) standards.

The Technical Challenges

There are a number of basic technical challenges that arise from military messaging deployments, some of which are particularly relevant to constrained communications channels. These are summarized below and will be illustrated in the scenarios described subsequently.

Low bandwidth. Many of the communication channels used are very slow, down to as little as 300 bits per second. With bandwidth this constrained, it is imperative that protocols make efficient use of it.
High latency. Very often, slow links have long round trip times. Satellite links are faster, but have very high latency. To work well in high latency environments, protocols should be “non blocking” as much as possible.
High error rates. Typical communication channels will often have high error rates, and applications must be robust to this.
Multicast. Many of the communication channels used are inherently multicast (e.g., radio, satellite). Messages are often sent to multiple destinations, and it is desirable that protocols can take advantage of the multicast nature of the underlying media. To some extent, this can compensate for low bandwidth.
EMCON (Emission Control). Deployed units will in many situations wish to not broadcast signals, in order to help hide their location. The situation where signals can be received but not sent is referred to as EMCON. It is essential to be able to send messages to a unit in EMCON.
Priority. Formal military communications have an associated priority (precedence). In a low bandwidth environment, it is easy for message queues to build up, and so it is critical to have mechanisms which will ensure that the highest priority messages get through first.

Key Features

Works with Microsoft Exchange server 2003 and 2007
Emission Control - ACP142 P_Mul ‘A Protocol for Reliable Multicast Messaging in Constrained Bandwidth and Delayed Acknowledgement (EMCON) Environments’ is a CCEB standard for multicast and EMCON support, specifically designed to support NATO’s STANAG 4406 Annex E.
Reliable Multicast to reduce the overall traffic on the network
General purpose data compression to help reduce data transfer volume for the protocol, addressing information and general data transferred (e.g. text). This compression complements application specific compression techniques for map and image compression for example
Supports mobile operations using radio based networks

Benefits

Reduces the cost of expensive satellite communications by using compression and multicasting.
Allows critical information to be supplied to users even when in “radio silence” by removing the need for “handshaking”.
Simple to use, preventing the need for specialist operational personnel.
Can be deployed with Microsoft Exchange and Active Directory, reducing cost of implementation, training, support and hardware.

Conformance

ACP 123, 'Common Messaging Strategy and Procedures', August 1997. ACPs (Allied Communications Publications) are issued by the CCEB (Combined Communications Electronics Board).
STANAG 4406, Edition 1, Version 3. 'Military Message Handling System', March 1999. (STANAG documents are NATO standardization agreements).
STANAG 4406, Edition 2. 'Military Message Handling System', March 2005 (to be ratified)
Annexe A: 'Military Message Handling System Extensions'
Annex E: 'Tactical MMHS Protocol and Profile Solution'
ACP 142, Version 1.0, 'P_MUL - A PROTOCOL FOR RELIABLE MULTICAST MESSAGING IN BANDWIDTH CONSTRAINED AND DELAYED ACKNOWLEDGEMENT (EMCON) ENVIRONMENTS'. December 2001.
Proposed Changes to ACP 142 version 1.0 (December 2001). NATO MMHS WG 642 (September 2004

Further information

A PDF version of this information is available in our reference library. Alternatively please contact us with your questions