By MAJ Matthew Penney, OC 103 SIG SQN
1. The generally accepted, historical architecture of Military communications has been based around 'protected' closed systems. This approach has required a significant investment in the construction of Military strategic anchor stations, whether that is Satellite Communications (SATCOM), High Frequency (HF), or via a private terrestrial backhaul.
2. The internet age has brought with it an enormous commercial investment in communications infrastructure that is highly survivable, and capable of passing Gigabits of data to all corners of the globe. The commercial and financial drivers underpinning this infrastructure can make it a far more reliable means for mission critical communications, with levels of response to service interruptions far greater than they have ever been before. The cost of these service interruptions can easily run into the millions of dollars, an amount that sees the level of businesses motivation to rectify outages far exceed that of the soldier on the wrong side of a displeased Chain of Command (as highly motivating as that should be).
3. The Royal Australian Corps of Signals, through the Chief Information Officer Group, is well placed to take advantage of these commercial networks. Flexibility through a wide range of options has been hard won through initiatives such as the Strategic Communications Modernisation Project - Land (SCMP-L). These gains must be replicated in the delivery of provisional and mature IP Battlefield Telecommunications Network (BTN) solutions in the future.
Scope4. This paper will briefly discuss two current strategic backhaul architecture models employed by Defence, and include some limitations that may be experienced in a highly contested environment. From this, a proposed Hybrid Architecture will be outlined to encourage open discussion on how military communications systems are interfaced, and more importantly the options available when traditional methods are not.
Aim5. The aim of this paper is to examine the opportunities available to create Hybrid Architectures for users interfacing into the Defence Wide Area Communications Network (DWACN). The architecture proposed is based on an 'ad-hoc' Strategic Tactical Entry Point (STEP) concept.
Background6. When discussing strategic 'rear-links' invariably the medium proposed is some variance of a SATCOM capability. The investment that the ADF has made into the Wideband Global SATCOM (WGS) program, with the tyranny of distance that confronts communication planners within Australia and on expeditionary operations, make this a sound choice. It is not until an operation is firmly established, potentially years later, that more reliable and capable terrestrial means are migrated to
7. This premise is supported since the introduction of SATCOM as a capability within the military; through examples in East Timor, Iraq, Afghanistan and other locations within the Middle East Region (MER). All examples have seen a heavy reliance on SATCOM, with a relatively late migration to terrestrial means, the most recent example being in the MER.
Method8. SCMP-L was a generational change which not only challenged the traditionally understood 'method' to connect to the Strategic network, but continues to allow innovation through enhancing the method by which that connection occurs. The SCMP-L diagram shown at Figure 1 highlights the breadth of bearers that can be leveraged for this connectivity, using a mix of Defence Back Haul IP and Internet IP.
9. The convention with SCMP-L is that the SCS-200 or SCS-400 will directly connect into the 3G, ADSL, Ethernet etc. with a lack of a presence of any of these meaning that routinely, a fall back to SATCOM is seen as the only viable alternative. As stated up front, the purpose of this paper is to encourage discussion about Hybrid Architectures. That is, in the author’s opinion, the options available when addressing the Strategic to Tactical Bridge, shown at Figure 2.
10. The area identified as the ‘Bridge’ will be the focus, as it is the area that affords the most opportunity in creating these Hybrid Architectures. The Bridge is the area through which a communications planning group can remove the restriction of cable length, which has traditionally been a limiting factor, and introduce a number of Military solutions to create additional flexibility.
11.  Closing this Bridge can be done a number of different ways. The proximity of the SCS-200 or SCS-400 to the Internet IP Mesh has generally dictated which method is used, or disregarded. The siting of a HQ element takes into account a number of different factors, of which physical security should rate higher than its ability to receive 3G/4G or ADSL connectivity. The lack of immediate proximity of 3G/4G or ADSL service should not see the exclusion of those methods, and professional communicators are obligated to find ways to overcome this shortfall. It is well understood that the ability to pass large amounts of data sees 3G/4G, ADSL or other terrestrial methods as a more attractive solution than SATCOM. Figure 3 and Figure 4 demonstrate how other military communication solutions can enable the 'Bridge' to be closed across significant distances.
12. The method shown at Figure 3 has been tested using a 3G/4G Modem to effectively ‘extend’ the Ethernet connection. The advantage that is afforded using this method is that all traffic passed from the SCS-200 or SCS-400 is black traffic, removing the need for a TACLANE or other encryptor at the remote end.