Satellite Network Management Systems: 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 network management systems (NMS).
Convergence is ongoing, and as enormous amounts of voice, video and data traffic flow throughout hybrid networks, the NMS has to react quickly and grow with each new addition to the network at hand. Responsiveness, adaptability and agility matter when it comes to NMS. With more 802.11 wireless links in the mix in particular, the complexity of the networking environment as a whole is increasing.
"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. "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."
In the background, developments are 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), 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 phrase "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 Tolga Ors, principal network/systems engineer at Intelsat. He serves as rapporteur for a group probing satellite and terrestrial interoperability at the International Telecommunication Union (ITU), which is in the process of standardizing MPLS, among other things.
"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 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 much 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 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."
Seeking Power Across Boundaries
ILC has a number of NMS projects underway. For example, NBC is tapping the company 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.
Nebraska Educational Telecommunications (NET) is expanding its Maxview NMS to now include monitor and control of all the digital transmitter sites throughout the state. The project began with the monitoring and control 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 Telmex project does not include satellite. The relevant point, however, 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."
Strict Rules Remain
M&C’s Gray sees most companies remaining quite firm when it comes to NMS boundaries, and the imposing of strict rules on the use of browsers running throughout the Internet. "Browser interfaces are okay when it comes 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.
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 (UPC) 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 integrated receiver/decoder monitoring, counteracting the system’s UPC. In addition to automated active controls, we see customers looking for 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 in the form of Effective Isotropic Radiated Power (EIRP) measurements using C/N, channel power or marker power algorithms. Spectral population monitoring uses simple power measurements or carrier masking algorithms.
"We too are seeing an increased need by our customers to control all remote sites from one location," says Earl Franklin, chairman of Asheville, NC-based Crystal Computer Corp. "This shift in operations, which includes centralcasting, business continuity/disaster recovery and network operations centers, allows the customers to decide whether to allow autonomous operation of remote sites or to allow central control of remote sites. Crystal offers all of these capabilities in our crystalvision NMC product line."
Crystal, which recently parted ways from ILC, is a supplier of real-time network management and control for the broadcast industry. Its customers include Fox, ABC, Disney Channel, ESPN, CNN/Turner, QVC and Sky LA. "In addition to adapting our services through this network control evolution, we are now offering leasing options, thus allowing our customers to realize these benefits now rather than later," Franklin adds.
Adapting To Network Needs
Satellite network operators are 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 are key objectives for companies like Inmarsat.
Last summer, Denmark-based Thrane and Thrane signed a 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 (RFS) 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.
What makes all this 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."
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 throughout the past three years to just under $200 million annually in commercial transponder leases, with this amount expected to increase.
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 (DSCS) Operations Control System (DOCS) soon to be renamed the Wideband Satcom Operations Control System (WSOCS) 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 (SCCE) 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, although it continues to use bent-pipe transponders rather than a processed payload, 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 (DAMA) for Very Small Aperture Terminal (VSAT) type networks tends to be the responsibility of the ground segment provider," Casady says. "This may change if turnkey systems like Hughes’ 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 already heavily invested in a full-blown hybrid fiber/wireless satellite network, 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."
Flexibility And Functionality
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 virtual private network (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. "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."
A second goal was to centralize the network control and administration. Another objective was to create a network where all services converged at layer 3 or IP. By running all services at IP, a ubiquitous network is created in which telephony, video and data become appliances plugged into the same infrastructure.
"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 customer’s network via the MAC address that is associated with the customer’s 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.
HDTV Challenges Network Managers
Readers have probably heard talk before about the low bandwidth alternative to MPEG-2, known as MPEG-4, which first started to roll-out in the late 1990s.
"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," says Robinett.
Increasing demand is 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 industry-wide 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 the one 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."
It’s Not Getting Any Easier
With industry-wide 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 in an automated mode, there appears to be no excuse today for lost bandwidth and the resulting diminishing revenues.
For a more in-depth discussion of NMS, including a look at commercial and military networking issues, see the unabridged version of this article at http://www.viasatellite.com.
Peter J. Brown is Via Satellite’s Senior Multimedia & Homeland Security Editor. He lives on Mount Desert Island, ME.