Web Exclusive: Satellite Network Management Systems: More Power And Precision
by Peter J. Brown
The satellite industry is looking for new opportunities while trying to keep up with the demand for more services. A steady proliferation of robust fixed, portable and mobile terminals, and the ongoing attempts by network operators and service providers to squeeze as much revenue as possible out of every link on the network are two of the elements impacting on network management systems (NMS).
Convergence is ongoing, and as enormous amounts of voice, video and data traffic flow seamlessly over hybrid networks, the NMS has to respond quickly, and grow with each new addition to the network at hand. Responsiveness, adaptability and agility matter when it comes to NMS. With more and more 802.11 wireless links in the mix in particular, the complexity of the networking environment as a whole is steadily increasing at the same time.
"The satellite network operator has to have his eye on advances in network management for any communications network," says Mark Krikorian, chief operating officer at Atlanta- based ILC Corp.–formerly Industrial Logic.
"Customers want to minimize operational costs, minimize operator intervention, increase efficiency, and increase reliability, which can only be found by utilizing specialized components and remote-capable systems," says Dewayne Gray, president of Plano, TX-based M&C Systems.
In the background, a lot is unfolding quickly with respect to digital video compression, and Multi Protocol Label Switching (MPLS), to name just two areas that could have a tremendous impact on NMS in the not too distant future.
How to best handle HDTV from the standpoint of video compression is definitely a network management issue, for DBS providers and TV networks alike. A new video compression standard is about to be approved. It is known as H.26L, H.264, MPEG-4 Part 10, AVC (Advanced Video Compression or Advanced Video Coding), and even JVT after the Joint Video Team, which is nearing completion of its work.
"Whatever the name, everyone agrees that the H.264 compression algorithm offers video quality equivalent to MPEG-2 at one half to one third the bandwidth," says Rob Robinett, CEO of Modulus Video Corp." Satellite broadcasters know they need it, but not when."
As for MPLS, it has already been implemented on the ground, and now satellite network engineers and designers are scrutinizing it as well for a variety of reasons.
The word "IP switch" is sometimes used to describe MPLS switching because MPLS enables IP routing protocols to be used on Layer 2 switches, making the Layer 2 switch (ATM or Frame Relay) an IP switch, according to Dr. Tolga Ors, principal network/systems engineer at Intelsat. He serves as rapporteur for a group probing satellite and terrestrial interoperability at the ITU, which is in the process of standardizing MPLS, among other things. See http://www.itu.int/ITU-T/studygroups/com13/index.asp
"It is not a big challenge any more to ensure the interoperability of satellite and terrestrial networks, but it is a challenge to do it efficiently," says Dr. Ors. "This efficiency is from a bandwidth and application performance point of view. ATM signaling, for example, is very heavy so using it for IP/ATM over satellite generates a lot of overhead. Standard MPLS signaling on the other hand is ‘light’."
"From a traffic engineering standpoint, MPLS could have a major impact. It is becoming increasingly apparent that satellite networks cannot exist in isolation," says Dr. Catherine Rosenberg, professor of electrical and computer engineering at the Purdue University School of Electrical and Computer Engineering. "I think MPLS over satellite is a very good idea. If you want to migrate ATM over satellite to something with an MPLS flavor, this can be implemented quickly."
She suggests that a lot of convergence between ATM and MPLS is taking place in terrestrial networks, and the same could be happening in satellite networks without much fanfare.
"An ATM-based satellite network architecture could be transformed relatively easily into an MPLS architecture," she says.
In a moment, we will visit a company that is implementing MPLS over satellite.
Seeking Power Across Boundaries
While the market for satellite NMS is not immune to the tough times that have descended on much of the rest of the satellite industry, this sector is not stuck in neutral. As far as sales are concerned, the curve has flattened considerably. However, some companies have suffered more setbacks than others have over the past 18 months.
Is the NMS sector seeing as many new large-scale start-ups today as it did a few years ago? There are numerous projects underway, but many involve expansions and network upgrades.
"The point you make is true. New start-up projects do not seem to be publicized much at all these days," says Krikorian. "That is why we are happy to be an exception. We have had 100 percent growth in 2002, with 14 new projects representing over 85 per cent of our revenue."
By the way, Crystal Computer Corp. and ILC have gone their separate ways after an attempted combination, which we reported on last year.
NBC is tapping ILC for backhaul management. MaxView will be used to simplify link scheduling to NBC affiliates, and to streamline data feeds.
"We can coordinate any number of remote sites, and then overlay a scheduling system on top of the NMS," says Krikorian, who adds that by combining subsystems, broadcasters can enjoy the added advantages of MaxView such as event correlation across technologies, and precise transmission plan scheduling.
At Nebraska Educational Telecommunications, for example, the expansion of its MaxView NMS will now include monitor and control of all the digital transmitter sites throughout the state. The project began with the M & C of the satellite uplink facility, and then expanded later to include distance learning equipment.
"This latest expansion further illustrates MaxView’s versatility in managing virtually any type of network equipment. It allows broadcasters to bring transmitter sites into the same system with the other components they want to manage," says Krikorian.
Telmex has embraced the MaxView Dominion in order to manage its data, long distance and switching networks. The project is part of a broad Telecommunications Management Network initiative to provide fault management, provisioning, performance management and security management.
"The Telmex project does not include satellite. However, the relevant point here is that they are using MaxView, the same exact product as our satellite customers, to manage equipment through other network management systems," says Krikorian.
"This speaks to a trend that has just begun–satellite network managers cannot afford to seek solutions that are targeted purely to satellite networks because truly universal network management systems will answer the needs of telecom, cable, wireless and satellite networks. Its power is transferable across sector boundaries," he adds.
ILC will provide a turnkey Manager of Managers for Telmex with regional network operation centers located throughout Mexico. The Manager of Managers will attach to various element managers, and perform fault management, configuration management, performance management and security management, according to Krikorian.
"The distributed architecture of the Dominion product will be used to reduce network bandwidth utilization, and permit the system to be scaled as the network continues to grow," he says, adding that with Dominion, all sorts of equipment using a range of standard–SNMP, Q3, CORBA–and non-standard or proprietary TCP/IP, serial and discrete interfaces can be managed.
Strict Rules Remain
A year ago, M&C Systems’s Gray discussed a number of NMS trends with Via Satellite readers, and one finds that not much has changed over the past year. Take the role of the Internet, for example. Gray remains enthusiastic about how life has been made easier for everyone, and TCP/IP-based automation tools continue to proliferate in areas such as automated alarm reporting where the connection and disconnection are done exclusively on a need basis over ISDN lines. But beyond that, Gray sees most companies remaining quite firm when it comes to NMS boundaries, and the imposing strict rules on the use of browsers running over the Internet.
"Browser interfaces are okay when it come to things like alarm data, but total remote site control from a browser is not going to happen. At least not for now," Gray says.
This does not mean that the pursuit of new approaches to Virtual Private Networks (VPN’s) is over, or that the process of identifying new security enhancements on the Internet has ground to a halt. Controlling routers is one thing, risking a massive disruption of a network is something else entirely.
"Customers these days are looking for networked systems that enable them to have a lights-out approach to monitor and control systems throughout their network. Customers want to have the capability of multiple, remotely operated systems controlled from one or more central locations," Gray says.
Various types of redundancy, Uplink Power Control (UPC), Built-In Test (BIT), and early warning systems at the local site have to be visible via the NMS. Virtual uplink power control for rain attenuation events needs to have the flexibility of using a variety of sources and control points for continuous service. Virtual downlink power control is also becoming an issue because network managers must accurately monitor the output chains.
"This allows the network operators to look at uplink signals prior to IRD monitoring, counteracting the systems UPC. In addition to automated active controls, we see customers looking for more and more pre-failure analysis," says Gray. "Now, there are early warning systems with BIT that have many automated Go/No-Go decisions with user configurable alarm criteria. We see more of these higher level functions being requested by many of our customers."
The early warning systems such as carrier monitoring use simple methods of relative power measurement; Effective Isotropic Radiated Power measurements using C/N, channel power, or marker power algorithms, while spectral population monitoring uses simple power measurements or carrier masking algorithms.
And what about Microsoft and the roll-out of the .Net platform, which is striving to take, network management to the next level in terms of implementation and reliability? According to Gray, while the .Net Framework is better understood in terms of how it is enabling a feature-rich application execution environment, it is stuck in low gear.
"It is slower than Microsoft expected. We have not sold any .Net systems yet, although we have quoted it. We use wireless PDA’s with the .Net interface to receive data from remote sites, but all this happens at the graphical user interface level, not at the backend."
Adapting To Network Needs
Satellite network operators are always looking closely at how they allocate spectrum and how effective their game plan really is when it comes to things like frequency re-use. Providing spectrum to the traffic handling systems that request it, and reclaiming spectrum from those systems that are no longer using it is a key objective for companies like Inmarsat.
Last summer, Denmark-based Thrane and Thrane announced its five year contract with Saskatoon-based SED Systems, a division of Calian Technology Ltd. Thrane and Thrane is providing the Radio Access Network to Inmarsat as part of Inmarsat’s Broadband Global Area Network (BGAN). SED’s Radio Frequency Subsystem and Global Resource Management (GRM) Subsystem are important parts of this new system.
"For the I4 satellite program at Inmarsat, the GRM dynamically manages the set of available payload frequencies, allocating them for traffic bearing systems such as the I4 BGAN, I4 Regional-BGAN and Inmarsat’s other existing and evolved services," says Pat Thera, SED’s business director for network management systems. "The I4 GRM assigns satellite payload based on both static and dynamic traffic requirements, and, performs real-time allocation for demand assigned services."
What makes this all possible is a rules-based engine that is able to adapt to the changing needs of the network, according to Thera. The rules not only allow the GRM to maximize frequency re-use when processing traffic demand, but the GRM also allows for these rules to be modified on the fly by the satellite operator without requiring any loss of service.
"This happens without shutting the system down. So, as more knowledge of new services and user behavior is gained, the behavior of the GRM can be modified without requiring a software upgrade," says Thera.
In addition, as each new type of carrier is added, it must be compared with all of the other carrier types in the network. The effect of the different carriers and modulation schemes must be carefully analyzed to ensure that when carriers are assigned to frequency blocks they do not affect the quality of service (QoS) provided.
"As users demand more service, it is important to re-use frequencies wherever possible in order to maximize the availability of all of the different services," says Thera. "The FPS being provided by SED assists Inmarsat in meeting that challenge by providing a wide range of features to model the various satellite payloads in Inmarsat’s constellation, the types of carriers and traffic profiles."
In the realm of comprehensive frequency planning tool sets, SED has pushed the envelope as far as possible. With these FPS tools, an operator can create optimal frequency plans based on visual depictions of the allocated spectrum. Interference can be spotted, and traffic patterns plotted. Thus, traffic demand problems are solved quickly without creating new problems in the process.
"It has certainly been one of SED’s largest technical challenges to date," says Thera. "Whether the service being provided is fixed or mobile, the allocated spectrum still needs to be managed and used as efficiently as possible."
Inmarsat has also upgraded their TT&C sites to include SED’s Monitor and Control System (MCS) which allows an operator to modify their NMS as the network changes. A drag and drop user interface on a tool called the Builder simplifies the process of adding new devices, reconfiguring the system and modifying the MCS behavior as required.
"This is critical for both satellite operators and service providers because their networks are always changing to keep up with the changing market conditions and demands from end users for new and better services," says Thera. "Another important issue is being able to interface to everything from legacy equipment, controlled via discrete inputs, to the latest RF and baseband equipment, controlled on a TCP/IP interface."
Meshing Military And Commercial
It is no secret that the Pentagon needs more bandwidth and that the commercial satellite industry has taken on an important new role as far as the Defense Department (DoD) is concerned. For one thing, the Defense Information Systems Agency has tripled its budget for commercial satellite capacity over the past three years to almost $200 million annually in commercial transponder leases, with this amount expected to increase.
However, there are two different cultures at work here, and what separates them is NOT the emphasis at DoD on high burst, real-time transmissions.
At the same time, the DoD has its net-centric operations flag flying high and the immense scale of the global operations of the U.S. military will result in a continued growth in bandwidth requirements and the need to determine what commercial and military satcom systems will be used to satisfy these requirements.
"The DoD’s approach for the management of their satcom resources utilizes centralized administration with distributed management of all assets–ground and space," says Mark Casady, vice president and general manager at the Communications Systems Group of ITT Industries, Systems Division.
Casady points to the wideband milsatcom control segment embodied by the current Defense Satellite Communications System Operations Control System (DOCS) soon to be renamed the Wideband Satcom Operations Control System with the launch of the Wideband Gapfiller Satellite (WGS) as a case in point.
"Elements of this control system are located at the worldwide level for long term planning and administration of functionality. Distributed management occurs at the network operations centers within each of the satellite areas of operation for overall satcom network control and at each of the earth terminals," Casady says.
"ITT Industries is responsible for the operational support, maintenance, and training for the DOCS. As far as control subsystems are concerned, ITT Industries built both the Satellite Configuration Control Element for managing the configuration of the communications payload on the spacecraft, and the Integrated Monitoring and Power Control System (IMPCS) for fault, performance, and configuration management of the ground segment resources which includes the earth terminals and their communications gear.
Among other things, WGS stands out because it continues to use bent-pipe transponders rather than a processed payload, and the channelization is done digitally, allowing for variable channel bandwidths. This provides a higher degree of onboard switching and recombining than traditional transponding satellites.
"Commercial satcom utilizes a different approach with control primarily applied at the satellite level by the satellite service provider. Network control such as spectrum monitoring, earth terminal control, monitor and alarm, and some degree of Demand Assigned Multiple Access for Very Small Aperture Terminals (VSAT) type networks tends to be the responsibility of the ground segment provider," Casady says. "This may change if turnkey systems like Spaceway are introduced in the commercial sector. If this happens, end-to-end service provisioning may open the door for a commercial version of IMPCS."
What also complicates the landscape is the question of how much of the control functionality should be on the satellite, where access and cost may be an issue, versus how much should be on the ground. Within the DoD there are differing philosophies as to how and where control of the overall satcom system should reside.
With the DoD heavily invested in a full-blown hybrid fiber/wireless satellite network already, Casady sees other unresolved issues that could have an effect on the current efforts by the DoD to complete the blueprints for its transformational communications architecture. The first cut at this is now expected to be finalized this coming summer.
"How the terrestrial segment will request service over the satcom segment is one of the key issues. What is the protocol that will be used for media access control (MAC)? Will this protocol be a derivative from existing techniques or will it have to be totally new in order to accommodate both segments being addressed?" asks Casady. "Will it use a circuit or packet-switched architecture or some combination of both? How will it support an end-to-end provisioning of QoS-based Service Level Agreements?
Resolution of these issues will require a more comprehensive and holistic approach to system management."
Reducing The Complexity Of Satellite Networks
As the issues that affect interoperability of satellite and terrestrial packet-based networks have become more clearly defined, work is now underway to define an architecture framework for satellite IP networks, to identify a QoS architecture supporting IP over satellite, and to enable multicast support for IP over satellite.
According to Ors, MPLS can help reduce the complexity of satellite networks where the support of IP QoS is a key objective, and this is true in instances where ATM is already in use. The constrained-based routing and aggregation advantages of MPLS, along with the multicast support capabilities are added benefits here making MPLS very attractive for satellite networks.
"MPLS can provide IP routing using ATM hardware. It also involves less bandwidth, and most importantly, the simplifying of network management due to much lighter signaling protocol," says Ors.
The availability of commercial off-the-shelf MPLS-enabled tools and hardware, and, the potential role of available signaling protocols–slightly modified through standards work to optimize them for the satellite environment–make this an even more attractive option.
"Perhaps the most interesting case is where the operators of broadband satellites with onboard switching elect to go with MPLS switching rather than ATM switching or IP routing in the sky," says Dr. Ors. "This would greatly simplify network management and network signaling, and enable simpler user terminals as well."
Most of the broadband satellite systems that took shape in the past decade planned to use an ATM switch in the sky with an IP over ATM overlay, a decision driven by the popularity of IP. This was not very efficient. According to Ors, not many broadband satellite operators wanted to deploy an IP router in the sky. The primary reason was the processing power and memory required for IP routers.
While this discussion of MPLS may seem a bit too futuristic to some readers, keep in mind about what was said earlier about how the DoD will mesh its full-blown hybrid fiber satellite wireless network with its net-centric agenda.
Achieving interoperability and establishing how exactly the terrestrial segment is routed over the satellite network remains open to question.
"Traditional circuit-switched services lend themselves to the more centralized administration/management with full period trunks with individual circuits established using time division multiplexing techniques," says one satellite industry executive. "Circuit-switched is also easier to handle on a preemption/priority basis in that circuits can be added and dropped based on the available capacity."
This all changes with packet-switched or net-centric architectures. The traffic model requires a very different approach to end-to-end QoS, not to mention TCP/IP over satellite.
"Unless the satellite has a router onboard, the inherent circuit-orientation of the satellite makes this problematic. Even with an onboard router, this is probably where the MPLS or GMPLS with policy-based management of the MPLS rules/queues will come into play to overlay the best of circuit-switched practices onto the packet-switched traffic," says this same executive.
"I would expect to see this area receive attention in both the military and commercial market segmentations. One of the key issues that needs to be addressed is how to articulate an abstract definition of a policy management rule or guideline–on a worldwide or area of operations scale–into a set of commands that can be implemented in a set of routers and ATM switches."
Not everyone is so sure that MPLS is the right way to go. Rob Robinett, CEO of Modulus Video Corp., questions whether MPLS really offers significant advantages over currently deployed solutions. Robinett served as director of engineering at Divicom, and was a co-founder of Skystream Networks.
"I have not seen it. One could argue that the promise of IP ubiquity across satellite networks has not happened as we expected. Most of the IP data encapsulation over satellite today is done over MPEG-2 using the DVB-MPE standard," says Robinett. "Implementing standard routing and VPN solutions are more cost effective solutions in this instance."
Robinett points to the lack of momentum for alternatives such as Unidirectional Link Routing (UDLR) which has been developed by France-based UDcast as highly relevant here. He views the limited acceptance of UDLR as an indicator that all VPN alternatives face a steep uphill climb. UDLR mimics a conventional bi-directional transmission atop an asymmetric link, where there is a high-speed forward satellite channel and a low-speed terrestrial back channel. A back-channel from a receiver to a feed is required so that all traffic that cannot be sent over the unidirectional link can be exchanged nonetheless via so-called "IP tunnels."
"UDLR has not taken the industry by storm. These forms of routing protocols can often introduce problems from the standpoint of security. So, given the lack of success of UDLR, MPLS over satellite proponents will need to make some very compelling arguments before this really goes anywhere," Robinett says.
"I would certainly disagree that UDLR has made slow progress to date," says David Finkelstein, managing director of UDcast North America. "UDLR is the only protocol of its sort to be approved as a standard-track RFC by the IETF. It is not surprising that other companies, trying to promote various proprietary protocols as standards, will tend to downplay the importance of a standard set by an international body. But it is only through the IETF standardization process that the Internet has progressed so rapidly, thanks to interconnectivity and interoperability."
Besides UDcast, the list of companies which have all developed UDLR-based products and services includes Alcatel, Cisco Systems, Data Planet, France Telecom, Hitachi, IDC, IPricot, Jsat, Sony, Thales Multimedia (Thomcast), and Vbox/Broadlogic.
"Interoperability between all these companies has been demonstrated, which is the real hallmark of an industry standard," Finkelstein says. "The satellite industry has in the past provided network services via a multitude of proprietary VSAT networks which are by definition private networks."
MPLS and UDLR are designed for different missions, although UDLR is also a tunneling mechanism that allows for diverse elements of a network to be put together, improving performance at lower cost in the process, according to Finkelstein, who stresses the fact that as a layer-2 protocol, UDLR renders the hybrid satellite/terrestrial links equivalent to layer-2 Ethernet-type connections.
"Since MPLS is a layer-2 protocol, it too will operate over a UDLR-enabled satellite link, just like it operates over an Ethernet LAN. UDLR will transport the MPLS packets over the satellite, and return them via the terrestrial network, using GRE encapsulation for the return path," says Finkelstein. "MPLS is in fact impossible to handle over many IP- over-satellite services, since they have generally been implemented at layer-3."
"There are not a lot of IP satellites out there to begin with, so as a result there is not much talk of IP routers let alone MPLS up on satellites at this point," says Dan Shell, network architect with the advanced technology team at Cisco Systems Global Defense and Satellite Group.
Shell views MPLS over bent pipe satellite as quite feasible. His team at Cisco Systems works closely with NASA Glenn Research Center, and NASA Glenn views the IP-based environment as an attractive arena for a variety of reasons. Among the advantages, it can open up the entire global ground station infrastructure to NASA enabling NASA to reduce substantially the life cycle costs of numerous programs by adopting a more IP-centric approach.
"People are being cautious. You have to keep in mind that the satellite providers are very risk averse. Where does MPLS fit? That is what people are still sorting out," Shell says. "We are just starting to see standards-based technology including a standard IP stack. We look at satellite as just another node on the network, not a proprietary piece of gear."
Replacing Virtual Tunnels Offshore With MPLS Over Satellite
So where might you encounter one of the first MPLS over satellite offerings? Try an oil rig in the Gulf of Mexico. An oil rig is like a beehive except the bees wear lots of different hats. In other words, these marine outposts are often swarming with lots of workers who represent several different companies. In order to address the telecom needs of multiple groups at a single site, Houston-based Caprock Services Corp. has implemented its IP Xpress Network, and selected MPLS over satellite as the core for its VPN offering.
"Today, Caprock operates a hybrid SCPC network in both symmetrical and asymmetrical configurations," says Steve Wheelis, director of product engineering at Caprock Services. "Currently in the final stages of review are the dynamic bandwidth managed networks which will be the underlying transport backbone allowing for much more flexibility and functionality of the service offerings."
Caprock Services begins the new year with its first fully operational MPLS over satellite customer, and tests are underway with another customer at press time.
"MPLS and IP have made life easier for us. There is no need to set up an exponential number of virtual tunnels," says Wheelis. "We also found that with MPLS over satellite, we can do much more at our network operations center in Houston."
As we noted earlier, using MPLS to support IP QoS is not uncommon in terrestrial networks. It represents the attempt to capture the best attributes of IP routing and the QoS advantages of either Frame Relay or ATM switching. MPLS is also a useful tool for traffic shaping or engineering, and it is sometimes referred to as a layer 2-1/2 solution meaning it rides between the datalink or switching mode which includes the MAC sublayer, and the network layer which incorporates IP addressing . If there are a lot of other companies running or attempting to run MPLS over satellite, we are unaware of them.
"Our primary goal is network flexibility. Caprock has accomplished this by offering two mechanisms to provide dynamic network configuration and provisioning, MPLS and traditional VPN tunnels" says Wheelis. "A second goal was to centralize the network control and administration. Another goal was to create a network where all services converged at layer 3, or IP. By running all services at IP, you create a ubiquitous network in which telephony, video and data become appliances plugged into the same infrastructure.
"MPLS allows customers to attach to Caprock’s network either at Layer 2 or 3 and then be put into an MPLS network implemented for just that customer. The customer can directly access their private network at any of Caprock’s sites on demand," he adds. "The network assignments are done dynamically and appear to be plug and play. The network knows to assign this particular device to the customers network via the MAC address that is associated with the customers phone, PC, or any other IP network appliance."
Traditional VPN tunnels are available for customers that either have their own VPN infrastructure, or wish to use the Internet for their VPN mechanism.
With the new network, all services can be provisioned centrally, as long as the appropriate hardware exists. Therefore, when additions, moves and changes occur, a simple plug in is required as long as the user is registered in the system," says Wheelis. "The Layer 3 network concept yields a much more cost-effective network where maintenance and administration is eased since there is only one network involved. This ensures that QoS is implemented to guarantee priority voice and video traffic, and Committed Information Rates as per customer requirements."
HDTV Challenges Network Managers
Readers have heard talk about compression breakthroughs before when the low bandwidth alternative to MPEG-2 known as MPEG-4 first started to roll-out in the late 1990’s.
"The Advanced Simple Profile which is part of MPEG-4 did not provide enough improvement in efficiency to induce broadcasters to adopt an alternative compression scheme. This all changes with H.264. Satellite broadcasters know they need it, but not when," says Robinett.
It all comes down to increasing demand being placed on a finite amount of satellite capacity, and this affects DBS and FSS operators alike. However, the timetable may not be driven by technology alone. Market variables and regulatory decisions on significant pending matters like dual carriage may set the wheel in motion for an industrywide adoption of H.264 sooner than we think.
"A lot of uncertainty surrounds the issue of dual must carry. Will the DBS service providers be forced by the FCC to comply with the must carry provisions that the DBS industry has battled against for the past two years or so?" asks Robinett.
In a nutshell, the DBS service providers are holding their breath. If they are required to carry the growing list of local HDTV stations as full HDTV offerings, all bets are off.
Robinett describes a potential migration to H.264 as a much easier transition and a much less dramatic leap than what the satellite and broadcast TV industries experienced when they jumped from analog to digital MPEG-2 transmissions.
"Because of the problem of what to do about the millions and millions of MPEG-2 equipped set-top boxes already in place, among other things, H.264 has to be backwards compatible," says Robinett. "You can mix H.264 with an existing MPEG-2 stream, so that for example, you might wind up with a cluster of SDTV MPEG-2 channels with one or more H.264 HDTV channels The MPEG-2 legacy decoders will simply ignore the H.264 stream."
Satellite NMS: Lots Of Action On The Water
This NMS snapshot will end with a quick look at a couple of recent exercises at sea. Ships and satellites work well together, and lots of folks are making sure that this partnership is in great shape going forward. However, the lessons here are quite relevant to what is happening onshore with respect to NMS as well.
Two significant U.S. Navy warfighting concepts play a key roll here. FORCEnet centers on knowledge superiority, and, the distribution and sharing of information across the battlefield, while Expeditionary Pervasive Sensing is a warfighting concept involving vast numbers of sensors distributed over the battlefield.
"The two concepts must work together. In order to command and control (C2) and move the data from vast numbers of sensors and turn that data into information and deliver it as knowledge, we need communications, networking and services to support on a scale of that order," says Guy Purser, director of engineering and director of modeling and simulations at the Naval Warfare Development Center (NWDC).
"We believe the agent-based computing technology holds great potential for the command and control of large numbers of sensors and as a means of "harvesting" the data into useful information. We have also experimented with the agents in ways that draws on the information and delivers it as knowledge to the war fighter," he adds.
The Navy plans to populate the battlefield with all types of sensors, doing so with some in very large numbers. Among other things, this presents a number of over the horizon communications challenges.
"The NWDC is looking at unique topologies. We have to develop both the network and the agent-based computing to support this pervasive battlefield information," says Purser.
In the process, Ku-band is under intense scrutiny here due both to the enhanced bandwidth advantage it enjoys over X-band, and the global footprint advantage over Ka-band. In many respects, the two above-mentioned Navy’s network-centric concepts mirror a telco with its blend of long haul or trunking, metro and local networks. With respect to strategic, tactical and operational networking options, NWDC is treating networks and networking–and bandwidth as a component of that–as a war fighting resource for future war fighting concepts such as FORCEnet. The Navy is beginning to do that as well.
"Just as owning the night was the high ground of the 1990’s, the next high ground is the information advantage," says Purser. "The current topology where bandwidth is controlled by the Navy Communications Station (NCS) may not be the best way to do things. In the future, the local commander may well wind up controlling that resource. This current way of doing things also involves a degree of vulnerability that we may want to rethink due to the fact that everything flows back to the a single point at the NCS."
The Satellite and Wireless Networking Section (SWNS) of the Naval Research Laboratory (NRL) has been tasked by the NWDC to examine and identify a number of commercial high bandwidth satellite options for the U.S. Navy. A series of Fleet Battle Experiments (FBE) have been used to test these satellite systems with the latest in the series, Fleet Battle Experiment-Juliet (FBE-J), taking place last summer off the coast of California. The FBE is a concept-base experimentation process that examines a number of issues besides satellite networking.
"NRL has been taking another look at Ku-band, and where satellite networks are headed," says Michael Rupar who heads the SWNS. "The use of small aperture terminals, and the ability to stand up independent of the ship’s link are both important. There is limited room for any new antennas aboard the smaller deck ships in particular, and there are electromagnetic interference issues as well."
Future relatively shallow-draft, high-speed warships in the 2,000 ton to 3,000 ton range possibly including trimarans will be taking shape as part of the Littoral Combat Ship Program, for example. These swift ships are going to require flexible and highly reliable satellite links.
In FBE-J, throughput rates in the 14 Mbs range were achieved using Sea Tel antennas, which have been used in four successive FBE’s. The Navy appears quite favorably impressed by Sea Tel’s overall reliability. Ku-band capacity on the SES Americom AMC 4 satellite was handled by Globecast. TDMA and FDMA networks were operating simultaneously on a shared basis over Viasat’s Linkway system. Comtech EF Data SDM 8000’s and 2020’s were used as well. NRL uses its own software solution for M&C.
"This was the largest pipe ever used in an FBE. NRL ran full duplex with a dual interdependent hubs onboard the USS Coronado (AGF-11) and onshore at the Fleet Combat Training Center Pacific. Four other ships participated as well including the Lockheed Martin Sea SLICE, and the high speed catamaran known as Joint Venture (HSV-X1)," Rupar says. "In the prior FBE, NRL hubbed off a ship for the first time."
With the shift to more littoral spaces such as the Persian Gulf, access to adequate Ku-band coverage is not an issue. Rupar and his team are well aware of the effects of rain fade, and they can throttle back if need be. The goal is to keep bits moving.
According to Purser, during the upcoming FBE-Kilo, the focus will be on more integration of agent based computing into the command and control arena.
"We will improve our networking and management services such as QoS. We will also take a good first look into mobile networking using a secure 802.11 network for the U.S. Marine Corps, using it as an ad hoc networking mode for ship line of sight communications," says Purser. "We are getting at the issues of how we will network the fleet in the years ahead with the DoD Teleport capabilities."
The U.S. Coast Guard is steaming ahead on a parallel course. In November, for example, the U.S. Coast Guard Cutter Neah Bay headed across Lake Erie with a Globalstar link, opening the door to a new era in mobile networking as it went. This team effort involved USCG, Cisco Systems Global Defense and Satellite Group, the NASA Glenn Research Center, Western Datacom and Scientific Research Corp.
A Cisco 3640 Router aboard the Neah Bay was used to seamlessly and continuously move IP traffic from an 802.11(b) wireless LAN/WAN out of Cleveland over to the Globalstar constellation with no reconfiguration of the router once the Neah Bay was some15 miles offshore.
"The ability to plug the router in wherever the user wants it greatly reduces the cost of mobility. This enables the user to access straight IP traffic, email, VoIP and multicasts," says Cisco’s Shell. "We could do 1 to 1.5 Mbs over the Cisco Aironet wireless 802.11b Ethernet LAN, and 64 kbs over Globalstar."
Hybrid wireless satellite networking is something that we have devoted lots of attention to in Via Satellite. While the fact that Globalstar’s low bandwidth satellite link cannot match the performance of a Cisco Aironet wireless 802.11b Ethernet LAN comes as no surprise, readers should be paying particular attention to the fact that the 802.11b LAN extends no further than 15 to 16 miles offshore.
Staying One Step Ahead
With industrywide consolidation a fact of life, NMS has to scale accordingly. Injecting a possible breakthrough in digital video compression along with a possible growing role for MPLS over satellite into the mix does not simplify the process either.
The good news is that the tools are out on the bench, ready to go. NMS vendors have worked hard to put a lot of power and precision at their customers’ fingertips. The network in question can be managed in a number of different ways, and whether done on a fingertip basis or an automated basis, there appears to be no excuse today for lost bandwidth and lost revenues.
Peter J. Brown is Via Satellite’s Senior Multimedia & Homeland Security Editor. He lives on Mount Desert Island, ME.