Developments in ISP-Infrastructure

by Friedemann Kuhnt, Product Manager IP-Services, DeTeSat Berlin, Germany

Introduction

Throughout the world satellite communications have become a very well known technology. It provides high quality, flexible and reliable solutions for voice, fax, video and data communications in public, as well as privately owned networks. The dramatic growth of data communication networks, for instance the IP-based Internet, ATM and Frame Relay networks, has led to a growing demand in IP-solutions. With such solutions the consideration of the architectural characteristics of the transport media is one of the key issues for an optimized design, and engineering of Internet and IP-networks.

Today, transport media is very common. It can be accessed through terrestrial cables, microwave signals or satellite communications. When comparing satellite communications to other forms of media you will notice tremendous advantages. Satellite communications technology is unrestricted to terrestrial bandwidth limitations, such as E1- T1. The flexible configuration allows every combination of receive and transmit speeds, which expands ISPs ability to upgrade the bandwidth according to it’s business needs. Furthermore, the excessive utilization of bandwidths in networks with asymmetric traffic flows, such as the internet, can be avoided by the use of simplex or asymmetric satellite link configuration eliminating the need for full duplex terrestrial lines. Satellite communications can be rapidly installed everywhere inside the footprint of a satellite, regardless of the existence of terrestrial infrastructure; in turn, making it possible to extend the internet into rural areas across the world. The price for a satellite link stays nearly constant inside the footprint of a satellite, allowing us to provide a more cost efficient alternative for expensive long distance terrestrial lines. Another major advantage of satellite communications is the broadcast facility. With one transmission via the satellite a large number of recipients can be reached, leading to optimal bandwidth utilization for more and more upcoming multicasting and content distribution systems, which are still producing congestion in terrestrial ISP-Backbones.

Figure 1 

Using satellite-based IP multicast applications to take congestion off the internet

The growth of the internet leads to an increasing amount of content in the network. This content is stored in central servers from where it is being sent to various users requesting specific data. A vast amount of data is frequently asked, causing the same amount of data to be unnecessarily routed via the same path in the internet to local ISPs. To save bandwidth and avoid retransmissions of data most ISPs are using local servers to store the content in small ISP networks, or POPs from where the information can be accessed at a faster pace by the final customer. There are two approaches when feeding the local ISPs with information. The traditional approach is to deliver the content via separate terrestrial internet lines, which requires for n destinations n times bandwidth. Current satellite based content distribution systems push the data from a content Hub and distribute it via the satellite with IP-multicasting to an arbitrary number of receive only stations in the ISP-networks and POPs. Our technology requires only one times bandwidth to serve an unlimited amount of receiving networks, being at the same time both fast and cost-effective. Various applications benefit from a satellite based multicast solution. Traffic is relieved from the terrestrial infrastructure and bypasses the data via a satellite broadcast stream. For example, distribution of Usenet News is now taking approximately 12 percent of the internet traffic, Web cache distribution will take even more. With a satellite Newsfeed the traffic can be transmitted more cost effective and with less bandwidth consumption. Web cache content distribution via satellite is an extremely efficient application to optimize an existing terrestrial ISP infrastructure.

With our T-SkyNet Internet & IP Services we offer specifically designed solutions for Newsfeed, File, Web Cache Content and streaming data multicast applications. These applications are all based on the TCP/IP protocol stack applications, and are mostly based on the point to point oriented TCP. Specific software packages for the commonly used operating systems Solaris, NT, and Linux were developed to provide a reliable multicast traffic mechanism from the Hub station to the remote sites. The software additionally provides encryption and compression of the multicast data. Special interfaces were implemented to be linked with commonly used terrestrial applications, e.g. the INN News Server, so making it effortless to integrate the solution into an existing terrestrial infrastructure. The multicast solutions we provide can be implemented either as a dedicated Hub at the customer site, or as a sharing of an existing Hub system at one of DeTeSat’s internet gateways in the United States or Europe.

Figure 2

Cost efficient and flexible bandwidth utilization with IP broadcasting

Satellite broadcasting is not exclusively used to distribute content on the internet. A further solution to optimize the bandwidth utilization of ISPs with IP-Broadcasting is the use of a shared IP-Hub-System. Consider the situation which is depicted on the left side of figure three. An ISP has a central IP-Backbone and it serves n POPs for its final dial in customers. To provide the highest possible quality of service for our customers, burst cases with 2 MB download capacity is necessary for each POP. In this case a terrestrial solution would require the installation of n 2 MB duplex leased lines to each POP.

A more efficient way would be the use of a shared IP-Hub broadcasting system (right side of figure 3). One 2 MB broadcast carrier is located at the central ISP backbone, which can serve all POPs with a maximum capacity of 2 MB. Specific filters are located at the receiver sites ensuring that the particular POP destined data is forwarded inside the POP network. To recognize the return channel, 64 K terrestrial lines are installed from each POP to the central backbone. The greatest amount of traffic from the Internet is routed via the satellite broadcast to the POPs. To optimize the delay of time, critical traffic such as DNS hookups and telenet policy routing can be used at the central uplink to route the critical traffic via the terrestrial lines with more efficiency. For the terrestrial approach the necessary bandwidth can be calculated as n x 2MB x 2. The bandwidth which is required for the satellite-based solution is 2MB + 2 x n x 64 K, expressing that the advantage of the IP-Hub broadcasting system compared to a terrestrial solution is growing along with the number of POPs.

Figure 3

DVB a new efficient transport media for IP

DVB (Digital Video Broadcasting) was originally designed to transport video and TV on a less expensive bandwidth optimized digital way with MPEG2-compression. The receiver hardware for this technology was developed for a mass consumer market and is therefore relatively low-priced. The DVB-equipment was also optimized in terms of the receiver parameters ensuring that inexpensive and small receive-only antennas can be used on the remote sides.

Throughout the growth of the IP market it became more and more attractive to integrate IP into DVB. Today, many vendors provide DVB compliant PC cards and set top boxes for the transport of IP. Currently, operators and ISPs are not only using DVB to deliver high-speed internet access via satellite to the final customer, but is also being used for the extension of their existing ISP infrastructure. Return channels are realized via the PSTN or terrestrial ISP network connections to draw the data from the internet.

Since this technical approach benefits from recourse sharing at a central broadcast uplink station, the bandwidth utilization is extremely optimized and cost-efficient. Additionally, it benefits from the MPEG2-compression and inexpensive receiver hardware developed for a mass consumer market.

DeTeSat Internet Access Gateways

DeTeSat is a 100 percent subsidiary of Deutsche Telekom. As a full-service provider for professional satellite technology DeTeSat offers via her T-SkyNet Services the complete VSAT product portfolio of global, fax, video, and data communication services for private and public network operators. The IP data communication belongs to one of the fastest growing business fields of DeTeSat. The company is world-wide active, cooperating with a large number of service providers, branch offices and representatives.

DeTeSat gateways in the United States and Western Europe offer high quality, powerful and reliable directly dedicated Internet access via satellite to major network exchange points. The US-gateways are located in the Washington area close to MAE-East. Excellent peering facilities to the MAE-East backbone (UUnet and AboveNet) and direct to the Sprint NAP (Tier1) are available here. The customers using these gateways are ISPs in South America, Africa and Europe, taking advantages of a powerful, direct Internet access to the North American Internet Backbone.

DeTeSat’s Internet Access Gateways in Germany are operated in Berlin and Raisting near Munich. Here, excellent direct access is possible to Western Europe’s most powerful Internet backbone, AS3320 of Deutsche Telekom and is provided to our customers. Deutsche Telekom brings every customer in fully direct transit via it’s own fibre backbone to the major Internet exchange points in the US, like New York Hudson, Sprint NAP or MAE-East. The target group for these gateways are ISPs and network operators coming from Africa, the Middle East, the CIS and South East Asian countries like India, Malaysia, Indonesia, Thailand or the Philippines.

With these three internet gateways, the company covers nearly every location world-wide. Highly skilled DeTeSat IP engineers ensure 24 hours a day and seven days a week a top level service quality. The backbone is permanently monitored and pro-actively managed, which gives all customers a great opportunity to expand internet business in a smart way.

Customer solutions for ISPs

T-SkyNet Internet & IP Services offer the full spectrum of customized ISP-solutions, such as dedicated backbone or trunk access, hybrid solutions and specific customer solutions.

Single-homed customers receive static routed IP-address space. Multi-homed ISPs are provided with the flexible and dynamic BGP4 routing. ISPs running BGP may get a fully optimized routing announcement in full transit to it’s backbone providers in the United States and Western Europe, ensuring a high quality availability of customer networks. At the link layer we provide duplex, asymmetric, simplex and broadcast configurations with bandwidth combinations, fully following the customers’ needs. In combination with simplex and broadcast, BGP multihop sessions with a terrestrial return channel are supported. SCPC, MCPC, or DVB technology can be used to implement the network services. According to the customers’ needs he will receive his own uplink equipment fully independent from DeTeSat Gateways at his own location. Network engineers fully support the customer to develop hybrid solutions and integration concepts for his network infrastructure, further more providing support for the installation, management and maintenance of the equipment. Additionally. DeTeSat offers the opportunity to share infrastructure resources and allow co-location space at the various gateways in the United States and Western Europe, where customers may rent rack space to locate their servers and routers directly to the backbone, also providing remote management access for the co-located equipment. The previously described IP-multicast applications, such as, File, Usenet News, Web cache content and streaming data distribution, are available at all DeTeSat gateways.

Via T-SkyNet Internet & IP Services customers have access to the complete choice of satellite service. All solutions mentioned in this article can be modified, optimized and adapted according to the customers’ needs. Highly trained sales and consulting crews analyse your demands to offer the optimal solution concept – may it be standardized or individual – , to match the customers’ “personal” communications needs and develop their internet business.

Figure 4 

If you need more information, photo or graphic material on this  article please contact:

DeTeSat Deutsche Telekom

Gesellschaft für Satellitenkommunikation

Hochstadenring 50

D-53119 Bonn, Germany

Tel: +49 (0)2 28 – 5 19 – 22 02

Fax.:     +49 (0)2 28 – 5 19 – 22 02

Contact Persons:

Friedemann Kuhnt, Product Manager, E-Mail: FKuhnt@detesat.com

Stefanie Falkenreck-Scheermesser, Marketing Communication, SFalkenreck@detesat.com