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Bandwidth is a term used in much of the telecommunications industry as a measure, usually expressed in bits per second, of the rate at which information moves from one electronic device to another. To the extent that people are aware of bandwidth issues in everyday life, they most often confront them in the form of a shortfall in bandwidth--awaiting retrieval of an (Internet) Web page over phone lines and modems that are too slow, for example, or being told on Mother's day to phone again later because no telephone lines are available.

Bandwidth is a central issue for any communications system. The U.S. Army's current battlefield communications system still largely reflects the days when the pressing need was for verbal messages that relied on battlefield telephones. The expectation that a phone system would suffice changed in 1991, when then Army Chief of Staff Gordon Sullivan began the service's digitization initiative. The initiative's goals were to significantly increase Army units' knowledge, in real time, of the disposition and combat capabilities of both friendly and enemy forces, thereby providing commanders with a common operational perspective, and to improve their ability to command and control their forces by speeding up the delivery of information. General Sullivan's vision was to exploit the ever-increasing speeds of the microchip--which, in practice, meant introducing onto the battlefield unprecedented quantities of computers, communications equipment, and software.

An explosive demand for bandwidth accompanied the initiative. Underlying it was an expectation of responsiveness--that information would be transmitted quickly. The (often unarticulated) model was the increasingly fast Internet service that the civil telecommunications industry was providing. For the most part, the demand for bandwidth in homes and offices was met in the mid-1980s and early 1990s by what was at the time redundant telephone capacity predominantly through copper wires, which had accumulated over almost 100 years. As that capacity was exhausted in the 1990s, the telecommunications industry increased the available bandwidth by laying thousands of miles of fiber-optic cable--a solution that, for the most part, is not available to Army troops on the move during battle.

Some personnel in the Army recognized that the bandwidth provided by the battlefield telephone system would be inadequate to support the goals of digitization. Nonetheless, the service did not fully realize the challenge that implementing digitization would pose to both its communications community and the wireless telecommunications industry in general. In particular, the Army did not know the size of its total requirement for bandwidth and had not considered the substantial difference in cost between using fiber-optic cable and using radios to satisfy that demand. (For an equal amount of bandwidth, cable is currently about 25 to 50 times cheaper.)

After a decade of effort, the Army's digitization initiative has fallen short of its goals;(1) the service's plans now focus on transformation, although digitization still remains an objective, albeit a subsumed one. (Transformation aims for significantly lighter and more easily deployable units that nevertheless have increased lethality and survivability compared with units today.) Consequently, the Army continues to invest significant amounts of money in new communications bandwidth to support its revised goals for digitization as well as new programs associated with transformation. The latter category includes the planned widespread use of unmanned aerial vehicles (UAVs), whose operation requires large amounts of bandwidth.

In this study, the Congressional Budget Office (CBO) analyzes the current and future total demand for communications bandwidth to support operations officers at all levels of command within the Army. CBO then compares that demand with the total bandwidth supplied by communications systems in place today and those planned for the future. Although numerous studies of Army communications bandwidth have been conducted, none has attempted to assess total demand and supply at all levels of command.

CBO's analysis is intentionally conservative insofar as it attempts, when there is doubt, to assess both future communications capabilities as being greater than they might be and future bandwidth demand as being less than it might be. Therefore, in cases in which CBO projects that future demand appears to exceed supply, this study may underreport the degree of mismatch.

CBO's analysis has yielded the following conclusions regarding the bandwidth available to operations officers. First, at all levels of command within the Army, the current demand for bandwidth is larger than the supply--shortfalls of as much as an order of magnitude (or up to 10 times the amount of supply) can exist. Second, shortfalls in the supply of bandwidth will persist at some command levels through and after 2010, when the capabilities associated with the Army's transformation begin to be put into the field. Thus, after what is now planned as an investment of approximately $20 billion in new communications equipment, the Army will fall short of its goals at certain command levels by an order of magnitude. (Unless otherwise indicated, all dollars are fiscal year 2003 dollars.)

Bandwidth Supply and Demand in Today's Army

At various Army headquarters in the field--for example, at the corps, brigade, or division levels of command--there are multiple communications networks. This analysis focuses on networks that serve the operations officers, denoted the ops desks or ops nets. Other communications networks (often located in the same command centers) are not unimportant, but in many cases they have similar equipment and are used to transmit similar amounts of information. (Examples of other communications networks are the intelligence and fire-support nets, which serve, respectively, intelligence personnel and personnel in the headquarters who control attacks on targets.)

Therefore, CBO's analysis of bandwidth supply and demand for the ops nets may illuminate supply/demand mismatches occurring in the Army's other communications networks.

Expressing the supply of bandwidth at each command level as one, Summary Table 1 displays the current relationship between supply and demand. Ranges are used for peak demand because only rough estimates of it are available. (The Army's data on peak bandwidth demand are a limited collection of experimental observations, test results, and simulations that have not all been obtained in consistent, controlled environments. In view of those limitations, CBO has reviewed its use of the available data with communications experts throughout the Army.) CBO's analysis focuses on peak demand because, with rare exceptions, it corresponds to the most intense battlefield activity, when failure is least tolerable.
Summary Table 1.
Effective Bandwidth Supply Versus Peak Demand in 2003, by Command Level

Command Levela Relative Supply Versus Peak Demand (S : D)b

Corps 1 : 1 to 4  
Division 1 : 5 to 8  
Brigadec 1 : 1.5 to 3
  1 : 20 to 30
Battalion 1 : 10 to 20  
Company 1 : 2 to 6  
Platoon 1 : 0.5 to 2  
Squad/Vehicle 1 : 2 to 6  

Source: Congressional Budget Office.
a. At the higher command levels, the table refers to the operations networks only. At lower levels, the distinctions between the various communications networks (for example, operations, intelligence, and fire-support) become less clear.
b. Based on an approximate logarithmic scale, the color coding is as follows: yellow indicates that supply is between about one-third and three times demand (a marginal supply/demand match); light orange signifies that demand is approximately three times supply, and orange, that demand is between three and 10 times supply. Red (used here for the lower brigade-level relationship and at the battalion level) means that demand exceeds supply by a factor of 10 or more.
c. The up-arrow (↑ ) indicates the throughput (bandwidth) rate for communications to equivalent or higher command levels. The down-arrow (↓ ) indicates the throughput rate to lower command levels.

The color coding in the table indicates how well the estimates of bandwidth supply and demand match. At no level of command is there a significant excess of supply relative to demand. If supply and demand are within a factor of about three (based on an approximate logarithmic scale), yellow is used to express caution. Caution is warranted for two reasons: modest delays in transmission are likely, with unknown effects on operations; and there is little potential to accommodate additional growth in demand.

The colors light orange, orange, and red indicate worsening degrees of mismatch. Light orange and orange correspond to increasingly long delays in message transmission or lost messages. Red--used in Summary Table 1 for the mismatch at the brigade level indicated by the down-arrow and the mismatch at the battalion level--means that demand exceeds supply by factors of 10 or more, resulting in severe operational effects. Computer memories, file systems, and network file servers overfill and sometimes "crash"; the network, or parts of it, fail; and command and control becomes "analog" as soldiers abandon the digital system and return to voice-only communications. (See Summary Figure 1 for a simplified depiction of the mismatch between bandwidth supply and demand that currently exists at different levels of command.)
Summary Figure 1.
The Army's Bandwidth Bottleneck

Source: Congressional Budget Office.

The reversion to analog command and control is an outcome reported both officially and unofficially in many of the Army's advanced warfighting experiments (AWEs) that were conducted between 1998 and 2001. The recent war in Iraq, by comparison, saw troops adopting a different approach. The Army provided them with a limited version of digitized communications (which nevertheless included the new capability of graphical displays of cumulative data), and units handled bandwidth shortfalls by using character-based transmissions (which are similar to ones from the terminal teletypes of an earlier era). Those messages were transmitted using e-mail and "chat room" formats (like those available over the Internet), which demand relatively little bandwidth.

Bandwidth Supply and Demand in 2010

Within the decade, both the supply of and demand for bandwidth on the battlefield are expected to increase substantially with the fielding of components of the next-generation Army. Key among them are the first units to be outfitted with the Future Combat System family of vehicles, the Shadow UAV, and a large amount of new communications equipment. The programs now generating that equipment are major elements of the Objective Force, the Army's current name for the lighter, more deployable force that it expects to have in place in 2010.

Advances in communications equipment that the Army plans to field include the Joint Tactical Radio System (JTRS), Warfighter Information Network-Tactical (WIN-T), and Multiband Integrated Satellite Terminal (MIST). The WIN-T and MIST are major components of the Army's plans to improve communications between the brigade, division, and corps command levels (known as the upper tactical Internet). The JTRS is the primary advance anticipated in communications between the brigade command level and smaller units (known as the lower tactical Internet). A number of features differentiate the two Internets; an important one is that the upper tactical Internet is augmented with satellite communications, whereas the lower is not.

In addition to the new communications equipment, the Army is considering a change in the internal architecture of its communications networks, which by 2010 would redistribute the information that those networks carry. A plan being discussed for the Objective Force would load all non-UAV information from the operations, intelligence, and fire-support networks onto a single "backbone net" and divert all UAV data to a separate high-capacity network.

By 2010, as Summary Table 2 shows, the most severe mismatch between supply and demand will have moved from the brigade level to the corps and division levels (shown in red on the table). That shift occurs because the JTRS, if it works as planned, will significantly increase the supply of bandwidth relative to demand in the lower tactical Internet. Further, at the lowest command levels, the JTRS will provide some capacity to accommodate additional growth in demand beyond 2010.
Summary Table 2.
Effective Bandwidth Supply Versus Peak Demand in 2010, by Command Level

Command Levela Relative Supply Versus Peak Demand (S : D)b

Corpsc 1 : 10 to 30  
Divisionc 1 : 10 to 30  
Brigadec,d 1 : 3 to 10
  1 : 5 to 15
Battalion 1 : 1.5 to 3  
Company 1 to 4 : 1  
Platoon 4 to 10 : 1  
Squad/Vehicle 7 to 20 : 1  

Source: Congressional Budget Office.
Note: The range in relative demand at the brigade and higher levels of command is associated with either the proposed "backbone" architecture or the case in which the current architecture is maintained and downlinks from unmanned aerial vehicles are heavily networked. (See Chapter 2 for details.)
a. At the higher command levels, the table refers to the operations networks only. At lower levels, the distinctions between the various communications networks (for example, operations, intelligence, and fire-support) become less clear.
b. Based on an approximate logarithmic scale, the color coding is as follows: green (used here at the platoon and squad/vehicle command levels) means that supply exceeds demand by approximately a factor of three or more. Yellow indicates that supply is between about one-third and three times demand (a marginal supply/demand match), and orange signifies that demand is approximately three to 10 times supply. Red (used here for the corps and division levels) means that demand exceeds supply by a factor of 10 or more.
c. If the architecture for information distribution located in the tactical operations centers at these command levels is altered, as the Army is considering doing, then operations officers will share information in a new "backbone net." In that case, the upper end of the projected range of bandwidth demand would apply.
d. The up-arrow (↑ ) indicates the throughput (bandwidth) rate for communications to equivalent or higher command levels. The down-arrow (↓ ) indicates the throughput rate to lower command levels.

At the higher command levels, however, the increase in the supply of bandwidth attributable to the WIN-T and the MIST will be swamped by substantial increases in demand, CBO projects. As a result, the new backbone nets, if implemented, will experience bottlenecks at the corps and division levels that are quantitatively similar to those existing at the battalion and brigade levels today.

Options to Mitigate Mismatches Between Bandwidth Supply and Demand

CBO examined several options to either improve the future match between bandwidth supply and demand or lessen the risk that the mismatch will be significant. Its analysis considered three general approaches: boosting the amount of bandwidth above the increases already envisioned in the Army's programs, reducing the demand for bandwidth, and better managing the mismatch between supply and demand.

CBO chose not to develop alternatives that would increase the supply of bandwidth after it analyzed two such approaches: funding efforts to develop new technology that would mature by 2010 or buying more of the currently planned systems. The technology approach is probably not feasible because the Army's planned new communications programs are already adopting all current and projected advances in technology. An approach that increases capacity by purchasing more equipment is also problematic. For example, some Army experts have suggested that projected bandwidth demand can be met by purchasing 20 times more sets of WIN-T equipment than the service is now planning to buy. However, current cost estimates for the WIN-T program already range between $4 billion and $9 billion, and additional spending of that magnitude may simply be an unlikely prospect.

The three alternatives described below suggest ways to eliminate lower-priority demand for bandwidth and better manage the demand that remains. The first two alternatives would stop the transmission of information that might be of lesser priority yet would be expected to contribute significantly to the future mismatch between bandwidth supply and demand at some command levels. The third would mandate the adoption of software tools, some of which are starting to become commercially available, that could allow better management of the demand for bandwidth when it exceeded supply.

  • Eliminate video teleconferencing, and in its place substitute teleconferencing plus a whiteboard capability.

  • Do not network UAV "downlinks." Maintain the autonomous sensor-to-shooter links (video downlinks from the UAVs), but do not transmit the video signals that they produce throughout the command structure, as the Army has planned. (Under this option, UAV video feeds would be sent directly to a single fire-support or intelligence center but would not be transmitted farther.)

  • Mandate that automated bandwidth management tools, which dynamically constrain the use of bandwidth and are now coming onto the commercial market, be built into the software that is expected to underlie both the upper and lower tactical Internets in 2010. The earliest such tools focus on network software; by implementing them and later extending them to applications software, the Army could manage future bandwidth shortfalls as they occurred and mitigate their effects.

1.  The Army planned as recently as 1999 to bring digitization to 47 brigades (32 active and 15 reserve) by 2009. As of now, however, it has abandoned its intention to digitize more than a two-division corps plus its support elements and is now focusing on digitization of the interim portions (the Stryker brigades) of the transformed Army's future Objective Force. The new goal is to digitize 13 units equivalent to brigades by 2009.

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