Bandwidth Management: All About Performance
In the midst of all these regional differences, and given the above-mentioned shift by several satellite operators to hybrid networking solutions, making decisions about how to best address bandwidth management issues on a per-day basis is not getting easier. For example, how to maximize channel utilization is one major challenge in particular for service operators who handle multiple users in an increasingly packet-switched, protocol-driven environment.
"Issues such as management of bandwidth among multiple users per bearer channel, and managing more complex satellite payloads require more sophistication in the satellite network infrastructure," says Patrick Thera, business director of network management systems at Saskatoon-based SED Systems, a division of Calian, which specializes in providing bandwidth management solutions to the satellite industry.
"Recent enhancements have included the ability to share frequencies between services in order to maximize channel utilization," says Thera." Besides providing real-time bandwidth management solutions, SED also supplies planning tools. With an extensive database of information and a sophisticated model of the satellite network, the Frequency Planning System can identify signal quality issues before they are manifest in the field."
Service providers and customers strive to keep their broadcast pipes fully utilized, and avoid buying pipes that are bigger than necessary. But what about the collection of content on the other end, prior to delivery or broadcast? This is extremely important as the industry begins to see such things as new push multicast Video on Demand via satellite services emerging, for example.
"As multicast applications have grown both in volume and diversity of traffic, and as the number of receive sites has expanded as well, the need to gather more content from multiple sources on the backend has also grown," says Bill Steele, president of CT-based Kencast Inc.
As a result, the same principles of opportunistic bandwidth management are now being applied to the collection of content on the backend, i.e., from the content source to the launch point or satellite uplink. Media DVX uses Kencast's Fazzt Satellite Publisher to collect multigigabyte files from 24 sites, point-to-point via satellite. This content is then routed to Panamsat's hub in Atlanta for subsequent multicast.
"If you have a capacity of 20 Mbs at the uplink, you can assure each of five content providers they will be guaranteed a minimum tunnel to and through the uplink of at least 4 Mbs at all times. If the other four providers are idle, a single active provider will see his throughput automatically accelerate to 20 Mbs," says Steele. "The result is a network that makes efficient use of bandwidth from end-to-end, from source to user."
So having the right planning tools and taking the time to optimize aggregation and the inbound feed from multiple sources is key to the successful management of satellite bandwidth. Service providers need to be sure they are hitting on all cylinders, at all layers. In other words, at the physical, data and application layers. At the physical layer, higher order modulation and forward error correction techniques are used in tandem with compression and Quality of Service (QoS) at the data layer. At the application layer, however, things either click or they do not. Operators can register bandwidth across satellite links based on channel load or application.
"The application and load IP packet switching allow bandwidth to go from shared to on-demand dedicated. A key ability is monitoring the traffic and establishing pre-determined policies to make decisions for the star or mesh configured networks," says Tim Floerchinger, vice president, sales and marketing at Comtech Vipersat Networks Inc.
Such solutions as Comtech's Vipersat platform strive to provide customers with a seamless IP-based infrastructure for satellite networking. Systems such as this one automate bandwidth utilization while optimizing space segment efficiency. They also automate shared to dedicated inbound channel switching and sizing based on channel load or application.
Because so many arrows point in the direction of overselling bandwidth with QoS, companies like iDirect have stepped up with a solution that enables operators to offer QoS no matter how much overselling is taking place, doing so across all network applications, routes and terminals. At the same time, all Service Level Agreements are easily verified by the operator via automatic state-of-the-art performance monitoring.
"Thanks to Multi-Frequency-Time Division Multiple Access (MF-TDMA) with fast hopping, iDirect increases the efficiency of space segment usage, and by being fast, load balancing is performed in a real-time manner," says Sasmith Reddi, senior technology analyst at iDirect.
Intelsat Ltd. includes both Comtech EF Data and iDirect products as part of its global service offering, according to Stephen Good, senior product manager of broadband and enterprise platforms for the satellite operator. Among other things, Intelsat is building its hybrid fiber/satellite networking, in an effort to better serve its customers' needs, allowing them to get the most from their allocated bandwidth.
"Intelsat currently operates several vendors' satellite access and transport platforms from companies such as, iDirect, Viasat, Radyne and Comtech. Intelsat will continue to operate these multiple platforms in its targeted regions and markets to ensure that we are satisfying the needs and preferences of all of our global customers," says Good. "Vipersat provides a number of advantages, including switched SCPC connections, Single Hop On Demand operation as well as enhanced coding and FEC techniques. At the same time, Intelsat has a multilevel traffic flow monitoring system that is used across its multiple platforms."
As for Comtech, Good says Intelsat is pleased that its Vipersat networks can be centrally managed regardless of the number and location of the operator's worldwide hubs, and also Intelsat is pleased with the ease with which clients can build networks, automate network efficiency and monitor and resolve issues.
As for iDirect, Good emphasizes that the scalability of the iDirect system allows Intelsat to scale as the network grows with the option of accessing up to five different satellites from a single chassis. iDirect is also a flexible solution that enables operators to increase or decrease the bandwidth assigned to specific TDMA traffic or applications bit by bit, rather than doing so using a rigid menu of established rates.
"iDirect provides strong performance enhancement via TCP acceleration, domain name system caching and compression features as well as automatic power control and turbo coding for efficient space segment usage," adds Good.
Managing The Balance
The practice of sound bandwidth management is constantly evolving, and a lot of new tools and new platforms are out there to help everyone do the job right. As for the global satellite bandwidth market, there are lots of tough decisions to be made, especially in Asia and Latin America.
The presence of mile after mile of dark fiber is not lost on the satellite industry, which has adopted a pragmatic and customer-driven approach as it moves from launch to launch. And with a new kid on the block in the form of Ka-band making its presence known, there will be more bandwidth, more options and more opportunities.
Peter J. Brown is Via Satellite's Senior Multimedia & Homeland Security Editor. He also volunteers as a satellite technology and communications advisor to the Maine Emergency Management Agency.
Email
Comments
Print
Reuse
