Signal support for XVIII Airborne Corps' first warfighter exercise

by MAJ Jonathan Mundt

Battlefield digitization is taking place throughout the Army in many forms. Many solutions are home grown, but all are helping achieve information dominance and increase maneuver systems� lethality. The XVIII Airborne Corps at Fort Bragg, N.C., demonstrated the capabilities of the newly fielded mobile-subscriber equipment tactical high-speed data network during its first Battle Command Training Program warfighter exercise March 2-9.

THSDN was critical to XVIII Airborne Corps� success during the warfighter exercise and is essential for supporting future deployments. Success stories included increasing battlefield situation awareness and dynamic collaborative planning. Command-and-control personal computers and InfoWork Space made this possible. THSDN greatly enhanced the corps� ability to C2, but data paths are filling quickly and will continue to grow for the foreseeable future.

The XVIII Airborne Corps warfighter exercise was embedded with 101st Airborne Division (Air Assault) and included 82d Airborne Division�s participation. An equally important exercise leading to the corps� warfighter exercise was the corps� warfighter ramp-up exercise in January that also served as 10th Mountain Division (Light)�s warfighter exercise.

Fort Bragg Signal-unit participation included 35th Signal Brigade (Airborne), 327th Signal Battalion (Airborne), 51st Signal Battalion (Airborne), 82d Signal Battalion (Airborne) and elements from 50th Signal Battalion (Airborne). Other Signal units participating included 501st Signal Battalion (Air Assault), Fort Campbell, Ky.; 10th Signal Battalion (Light), Fort Drum, N.Y.; and elements from 93d Signal Brigade, Fort Gordon, Ga., and 11th Signal Brigade, Fort Huachuca, Ariz.

Network architecture

Since 82d Airborne Division�s THSDN fielding in November 1999, XVIII Airborne Corps has been designing and installing tactical networks that were a hybrid THSDN and tactical-packet network. The XVIII Airborne Corps� warfighter exercise was the first pure-THSDN corps network installed to date.

The XVIII Airborne Corps� tactical network included six single-shelter switches, 13 node-center switches, eight forced-entry switches, 29 small extension nodes, one AN/TYC-39A message switch, 13 network-encryption systems, more than 70 routers, 29 servers, 13 multichannel tactical-satellite terminals and seven digital group multiplexing terminals (following figures).

MSE diagram Phase I Mobile-subscriber equipment diagram for Phase I of the XVIII Airborne Corps' tactical network.
MSE diagram Phase II MSE network diagram, Phase II of XVIII Airborne Corps' tactical network.

Simultaneous BCTP exercises required long-haul communications to link XVIII Airborne Corps and its divisions. TACSAT links met the challenge, providing critical wide-area network extension for collaborative planning and access to Defense Information Services Network.

The 35th Signal Brigade extended DISN services, including secure Internet protocol routed network, nonsecure IP routed network and Defense Switched Network through two standard tactical-entry-point gateways. Installation support provided local access to NIPRNET through both gateway NES and modems.

Support for unique requirements involved installing special circuits. The 35th Signal Brigade engineered and installed a dedicated TACSAT link to support military-intelligence circuits from BCTP to the corps� main command post. Elements from 11th Signal Brigade and 35th Signal Brigade combined efforts to install critical links to Third Army at Fort McPherson, Ga.

Lessons-learned during 10th Mountain Division�s warfighter exercise revealed the need for direct, high-speed data links between CMAIN and the corps� rear CP to support collaboration tools. The 35th Signal Brigade used DGM terminals from 327th Signal Battalion and Fort Gordon�s 63d Signal Battalion. Three DGM links with data rates of 2,048 kilobits per second, 1,024 kbs for voice and 1,024 kbs for data did the job. After CMAIN jumped, high-speed DGM and fiber-optic links maintained the critical CMAIN-CRCP data paths.

During 10th Mountain Division�s warfighter exercise, the corps installed a network stretching among Fort Drum, Fort Campbell and Fort Bragg. A critical engineering feat by 10th Signal Battalion involved using battlefield videoteleconferencing that required considerable bandwidth. Equally critical for BVTC was ensuring data redundancy and placement of the multipoint conference units.

One way 10th Signal Battalion reduced data congestion was by doubling the standard division-main-to-division-rear interswitch link from 1,024 kbs � with 512 kbs for voice and 512 kbs for data � to 2,048 kbs. Increasing bandwidth between two major CP sites and strategically placing MCUs at DMAIN and DREAR were the keys to success.

Monitoring the data link when DMAIN jumped revealed 800 kbs of the available 1,024 kbs consistently used during the battle�s last hours. This was attributed to BVTC�s heavy usage and the less-perfected enforcement of the digital rules of engagement.

Network management

Managing the tactical network was clearly a team effort. Each Signal unit and G-6 staff played an important role for ensuring reliable voice and data services to the warfighting customers.

Brigade and battalion systems-control centers managed the tactical WANs, while the corps and division G-6 managed the tactical-operations center�s local-area networks. To more efficiently manage the WAN (containing more than 70 routers), the network was divided into three autonomous systems. The 35th Signal Brigade managed the corps-to-division gateway links between autonomous systems. The brigade, along with its subordinate 327th and 51st Signal Battalions, managed the corps autonomous system, while 501st Signal Battalion and 82d Signal Battalion managed their divisional autonomous system. During 10th Mountain Division�s warfighter exercise, 10th Signal Battalion managed its divisional autonomous system.

Each autonomous system used open-shortest-path-first networking protocol to advertise internal routing while using border-gateway protocol between the corps and division autonomous systems.

The tools used to perform network management varied between SYSCONs. Corps G-6 also used both hardware and software LAN-management tools to ensure network reliability and prevent high-network collisions.

The primary router-management tool used in SYSCONs was a commercial software product from Castle Rock called SNMPc. SNMPc was tested during previous exercises and chosen due to its ease of discovering the router network and ability to quickly train network technicians. The following figure is a SNMPc picture showing the corps� autonomous systems with gateway links to the divisions and DISN.

SNMPC screenshot showing system and gateway links SNMPc screenshot showing corps' autonomous system with gateway links to the divisions and DISN.

More network-management tools used in the SYSCONs were the reporting-and-planning terminal that Communications-Electronics Command of Fort Monmouth, N.J., fielded to compliment the THSDN fielding. What�s Up Gold software provided on RAPTer was used by SYSCONs, along with SNMPc. What�s Up Gold uses a "ping" to verify the ability to resolve to another router, but it doesn�t provide individual link status. SNMPc polls the network interface using Simple Network Management Protocol, providing real-time status of IP unnumbered router links. SNMPc also simplifies standard "telneting" into routers to provide Cisco Discovery Protocol and OSPF neighbor status.

To complement router network-management tools, SYSCONs continue to use the network-management center to view and troubleshoot the voice network. Though the data network-management tools provide a link status, NMC provides a secondary network picture to validate router status and to identify catastrophic failures such as switch outages in real time.

The 35th Signal Brigade also used the newest generation of Army network-management tools known as integrated-system control, fielded in November 2000. ISYSCON�s network-management tools include HP Openview and Cisco Works. Though not extensively evaluated during the warfighter exercise, ISYSCON is expected to greatly enhance SYSCON�s management capabilities.

The 35th Signal Brigade�s plans cell extensively used ISYSCON network-planning functions for planning and exercising MSE assets in the BCTP scenario. ISYSCON was a proven replacement for the current generation of network-planning terminals, but light forces require a laptop version to support contingency operations.

The increased bandwidth THSDN provided greatly enhanced data throughput, but performance management was critical for preventing data-path saturation. The 35th Signal Brigade used a commercial-software package from Concord called NetHealth to perform bandwidth analysis and provide trend analysis. NetHealth provided a near-real-time link trend analysis and was used in conjunction with the corps� battle rhythm to evaluate critical-event impact on data throughput.

NetHealth bandwidth-usage charts shown in the following figure were used by 35th Signal Brigade�s systems engineers to evaluate network modifications. G-6 used the bandwidth analysis for evaluating adherence to the information-management guidelines known as DROE. DROE will be discussed later in this article.

Bandwidth-use charts Bandwidth-utilization charts for XVIII Airborne Corps' warfighter exercise.

At CMAIN and CRPC, the corps G-6 used SNMPc and What�s Up Gold to monitor servers� status and access to the tactical WAN. At the LAN level, G-6 used SnifferPro and Observer software to troubleshoot LAN connectivity and identify "top talkers." "Top talkers" were network users who used a high percentage of the available bandwidth. To troubleshoot LAN cabling, G-6 used Microtest�s Compas and Fluke�s Onetouch Series II hand-held testers.


The corps� warfighter exercise marked the first time CMAIN jumped. Tactics, techniques and procedures developed and tested during the January ramp-up exercise made the jump a success. Jumping CMAIN also meant installing a tactical LAN in an austere location normally provided by Fort Bragg�s Information Technology Business Center.

Another first was that computers clearly outnumbered telephones in CMAIN. G-6 administered three servers in CMAIN for webpage, electronic mail and IWS services. CMAIN requirements included 144 tactical telephones that averaged 794 calls per day and 190-plus computers that averaged 4,456 emails per day. The CMAIN webpage received an average of more than 580,000 hits per day. Of the 121 Army tactical C2 system workstations in the network, 18 were at CMAIN.

The CMAIN LAN installed during the corps warfighter exercise overcame the limitations of low-end switches and hubs used during the January exercise. G-6 connected Cisco 4006 switches in a layered, mesh configuration that acted as TOC routers. Fiber-optic cable supported the long distances between switches with Ethernet and coaxial cable used for shorter client lines. The Cisco 4006 switches provided 100 megabits per second speeds between switches, enabled CMAIN and CRCP to use virtual LANs and reduced the collision domain.

Multiple router paths from Cisco 4006 switches to THSDN Cisco 3640 switch routers � provided by 327th Signal Battalion � ensured redundant network access to corps and division CPs. The following figure shows network connectivity for CMAIN.

CMAIN CP network connectivity Corps-main command post's network connectivity.

CRCP used a similar LAN structure to CMAIN but on a smaller scale. The corps G-6 installed and managed a Cisco 4006 TOC switch with dual Ethernet connections to THSDN Cisco 3640 routers. The 51st Signal Battalion supported CRCP and dual-homed the Cisco 3640 routers, providing further high-speed redundancy. A standard adopted at all major CPs included a redundant MSE switch and dual-homing the THSDN routers.

101st Airborne main CP

During 101st Airborne Division (Air Assault)�s warfighter exercise, the division G-6 and 501st Signal Battalion implemented two new technologies to speed up the data network, with excellent results. The first improvement was implementing manageable LAN switches at division TOC sites. G-6 used HP4000 managed switches, giving each user his own collision domain. Using HP4000 resulted in network users experiencing virtually zero errors or collisions, and switch-port use of 50 percent or lower.

The other advantage of using a managed switch was the ability to selectively set a higher service priority. High-priority users experienced significantly faster data-transfer capability with corps and throughout the division. The following figure shows 101st DMAIN connectivity.

101st Airborne Division DMAIN CP connectivity Diagram of 101st Airborne Division's division main command-post connectivity.

The second implementation was installing two 100 megabytes-per-second Fast-Ethernet cards in THSDN 3600 routers supporting DMAIN and the division warfighter center. Fast-Ethernet cards connected to HP4000 switches increased the TOC-LAN-to-WAN connection speed from 10 mbps to 100 mbps. Network access greatly improved, since 75 percent of all users logged into the servers at these two locations.

In addition to using HP4000 LAN switches, 101st Airborne Division�s G-6 and 501st Signal Battalion used smaller HP2524 managed switches in DMAIN and DWFC, helping decrease cabling in the TOC. Because the switch provides separate collision domains, each user still experienced the same bandwidth as if he was connected to the HP4000.

10th Mountain main CP

The 10th Signal Battalion installed and configured Cisco 3600 series routers as edge devices at division CPs and at SYSCON. These devices served two functions. First, they provided redundant data paths out of critical CPs by using two Ethernet ports as WAN uplinks to two different MSE switches. Second, they functioned to break up large collision domains within DMAIN and DREAR.

At 10th Mountain Division�s DMAIN, there were 106 processors executing various tasks. All these processors were divided into smaller collision domains across the Cisco 3640 Ethernet connections. Although this architecture reduces network congestion in the CPs, it doesn�t eliminate the problem. A future enhancement includes migration to a combination of managed switch and CP router.


IWS was the most powerful tool XVIII Airborne Corps implemented. IWS, produced by General Dynamics, is a synchronous collaboration tool that provides simultaneous virtual environments. IWS supports whiteboarding, file sharing, audio, instant messaging and real-time presentation viewing. IWS servers create large, online virtual conference rooms, virtual auditoriums, file storage and user accounts.

XVIII Airborne Corps used IWS for three key functions to enhance battlefield situation awareness: virtual-conference hosting, ad hoc planning sessions and significant-action posting in near-real-time. Virtual conferences replicated the twice-daily staff update and commanders� conference call to the corps commanding general. IWS conferences involved an average of 50 or more simultaneous users.

IWS improved coordination and reduced travel by allowing the staff and commander to remain in their workcell or TOC, brief their slides using a preloaded presentation on the server and use an audio headset to interact with the commanding general. An added function, online "chatting" using instant messaging, avoided interrupting the briefing and provided continuous updates. The ability for the commanding general to provide direct guidance and influence major subordinate commands simultaneously made IWS a powerful C2 tool.

"Recent advances in Signal architecture and information systems have transformed C2 in XVIII Airborne Corps� corps-level CPs," said BG David Petraeus, XVIII Airborne Corps� chief of staff.

Other emerging technologies

Another crucial tool XVIII Airborne Corps used during the warfighter exercise was C2PC. The corps lacks the maneuver-control system to provide a common operational picture, so it chose C2PC based on the Marine Corps� success with C2PC and its ability to interface with Global Command and Control Systems-Army.

Corps G-3 installed seven tandem servers to host C2PC clients throughout the corps and divisions. Individual staff/unit elements updated COP graphics and unit icons on the server that ultimately updated client workstations in each CP. The corps only scratched the surface of C2PC capabilities, but C2PC clearly enhanced situation awareness at every corps, corps separate and division CP.

C2PC also provided a new capability to 35th Signal Brigade. As COL Jeff Foley, the brigade commander, said, "This is the first time the Signal brigade had a COP � very useful in our own environment. We used it to gain visibility of logistics-support systems, status of major supply routes, locations and status of Level II and III reaction forces, base-cluster composition and lines of communications for force-protection challenges."

While the COP software XVIII Airborne Corps uses is C2PC, 10th Mountain Division continues to use MCS (Light) for its common tactical picture. MCS (Light) is a "leave behind" from 10th Mountain Division�s participation in the joint-contingency-force advanced warfighting experiment.

The 10th Mountain Division currently has more than 75 MCS (Light) laptops and continues to enjoy great success with MCS (Light) as a platform for a CTP. The 10th Signal Battalion installed and maintained the MCS (Light) server, but the division G-3 remains the battlefield-operating-system "owner." MCS (Light) doesn�t interface with C2PC, requiring the division G-3 to execute a "swivel chair" data transfer to ensure the corps COP is kept up-to-date.

XVIII Airborne Corps also experimented with BVTC. The program manager for Warfighter Information Network at Fort Monmouth provided five endstations and two MCUs. G-6 installed endstations and MCUs in CMAIN and CRCP, and issued one endstation to each division and to 2d Armored Cavalry Regiment. MCUs provided multiparty videoconferencing that would otherwise be point-to-point between endstations.

Operationally, the corps� leadership considered IWS a more useful tool than BVTC. IWS improved situation awareness and provided substantial collaborative capabilities without the need for live video.

Another "leave behind" from JCF AWE was 10th Mountain Division�s BVTC system. They received five sets of Polycom cameras as well as MCUs. Initially planned for specific updates and virtual meetings, during the final 36 hours of the warfighter exercise the BVTC remained on continuously between the division CPs and two brigade TOCs. Contrary to corps� experience, the BVTC system at 10th Mountain became a constant virtual battle-planning and coordinating tool.

During the battle�s execution, BVTC became the primary means for continuous updates, issuance of orders and directives, and a means for intelligence dissemination. In short, 10th Mountain Division fought the final battle using BVTC as the primary C2 means within the division. The 10th Signal Battalion anticipates leaders will expect this system in the future.

To make the new information systems operate over THSDN wasn�t an easy task. Systems such as email, webpages, C2PC and ATCCS were supported with established protocols; IWS and selected BCTP systems created an engineering challenge.

Since fielding THSDN, Signal units attempted to create standardized router tables to simplify network installation. Realizing IWS and BVTC require robust data rates, unicasting protocols were soon determined to be bandwidth-wasters. To overcome bandwidth requirements and support nearly 60 simultaneous IWS users scattered throughout the division and corps networks, Protocol Independent Multicast routing was injected. PIM provided multicasting from the IWS server at CMAIN and CRCP to clients at each TOC. Multicasting minimized the impact on links that couldn�t be dedicated for IWS. IWS uses transmission-control protocol/IP to send data, and shared desktop information, instant messaging or whiteboarding and User Datagram Protocol for voice.

Other standard router configurations included route summarization to minimize the size of the router table and have fewer lines to troubleshoot. However, many BCTP systems and ATCCS required static routes. Though not desired on a larger scale, limited static routes in selected routers or switches were manageable.

Early in the warfighter exercises, the corps G-6, corps G-3 and 35th Signal Brigade recognized that THSDN could invite information overload. To avoid saturating THSDN from the start, Petraeus approved DROE to keep bandwidth expectations within reason. Initially published as a fragmentary order and ultimately published in the operations order, the "digital rules of engagement" term was coined to stress that digital capability is a warfighting resource.

DROE parameters included standards for server administration, IWS procedures, email attachment limitations, webpage design, video use and responsibility for enforcement. DROE was well received by users and ensured maximum data throughput while avoiding 30-megabyte PowerPoint file transfers.

Summary: looking to the future

The XVIII Airborne Corps� warfighter exercise was a great success for the maneuver units and especially for the dedicated Signaleers. The exercise didn�t tackle all the challenges that lay ahead in digitization within XVIII Airborne Corps, but it established some critical TTPs to enhance the warfighting capability stressed by BCTP. This was truly a success story for THSDN and the Signal Regiment.

XVIII Airborne Corps will continue to adapt and refine lessons-learned for the next iteration of warfighter exercises � 82d Airborne Division and 3d Infantry Division (Mechanized) in January 2002. The power demonstrated by IWS and C2PC for C2 synchronization has set the standard for the future.

"Though THSDN has been terrific, we already see the need for bigger pipes!" said Petraeus at the warfighter exercise�s conclusion. "Requirements already on the horizon will drive the need for greater bandwith increasingly upward. We�re already having to establish DROE and to use network-management tools to intensively oversee the increased-bandwidth use THSDN brought."

We can�t rest on our laurels. THSDN increased data throughput for processing battlefield information and improving battlefield collaboration today, but it�s only a stopgap measure for the needs of tomorrow. DROE enforcement prevented saturating THSDN paths, but use of enhanced video and web-based collaboration tools will shortly exceed THSDN�s capabilities. We must remain vigilant in our quest for keeping ahead of the warfighter�s needs.

MAJ Mundt is 35th Signal Brigade�s systems-engineering officer. His 15-year career includes service in Signal units at division, corps and echelons-above-corps with duty assignments at Fort Ord, Calif., and Fort McNair, Washington, D.C. He has also been assigned to Signal units in Germany and Korea, and for the past two years at Fort Bragg. His civilian education includes a bachelor�s degree in electrical engineering from Norwich University and a master�s in systems management from Golden Gate University. Mundt is also a graduate of the Signal officer�s basic and advanced courses, the Tactical Signal Staff Officer�s Course, Combined Arms Services Staff School and the Command and General Staff College.

Acronym QuickScan
ATCCS � Army tactical command-and-control system
BCTP � Battle Command Training Program
BVTC � battlefield videoteleconference(ing)
C2 � command and control
C2PC � command-and-control personal computer
CMAIN � corps main (command post)
COP � common operational picture
CP � command post
CRCP � corps rear command post
CTP � common tactical picture
DGM � digital group multiplexing
DISN � Defense Information Services Network
DMAIN � division main (command post)
DREAR � division rear (command post)
DROE � digital rules of engagement
DWFC � division warfighter center
IP � Internet protocol
ISYSCON � integrated-systems control
IWS � InfoWorkSpace
JCF AWE � joint-contingency-forces advanced warfighting experiment
Kbs � kilobits per second
LAN � local-area network
Mbps � megabits per second
MCS � maneuver-control system
MCU � multipoint conference unit
MSE � mobile-subscriber equipment
NES � network-encryption system
NMC � network-management center
NIPRNET � nonsecure Internet protocol routed network
OSPF � open shortest path first
PIM � Protocol Independent Multicast
RAPTer � reporting-and-planning terminal
SYSCON � systems-control center
TACSAT � tactical satellite
THSDN � tactical high-speed data network
TOC � tactical-operations center
TTP � tactics, techniques and procedures
WAN � wide-area network

dividing rule

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