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Which Solution, Which Service, Which Product

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Ex Member
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Jan 15th, 2009 at 2:35am  
Although I've been in the IT industry for many years, I'm new to Broadband over Satellite and I have a few question that will help clear things up in my mind. I have read quite a bit on this forum which by the way Eric, is a fantastic one with some great info and I think I've grasped some things although I have a million question. These are general questions but they are also specific to the Middle East region.

We are a small operation, +-30 people scattered across a few sites in Afghanistan (Kabul) and Iraq, and we want Internet Connectivity and VPN connectivity between sites. We require more efficient Internet Connectivity than we have had until now. Up until now the service has been radically unreliable, regardless of the various ISP's and this needs to change.

I'm an outsider coming in to find the best solutions for them but I need any input from anyone out there regarding Internet Services in Afghanistan.

1. I'm presuming that the only and best method of getting some sort of reliable service is to use a Satellite service. Is this correct or am I off the mark completely?

2. After some reading I see that the best low latency and weather "resistant" solution out there is iDirect. Is this correct or are there alternatives which are not bad in comparison?

3. I also presume because the iDirect solution can be a "one box" solution it can be used as a lower entry product and a far simpler implementation than others? Almost a plug and play solution?

4. When it comes to the various Satellites, AM22, Eutelsat W6 and NSS6 which I think are the only ones covering the Middle East pretty well, which one is best suited to Internet Broadband for small size operations?

Any real grassroots advise would be welcome.

Thank you.
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Eric Johnston
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Reply #1 - Jan 15th, 2009 at 10:15am  
Quote:
2. After some reading I see that the best low latency and weather "resistant" solution out there is iDirect. Is this correct or are there alternatives which are not bad in comparison?

No. All geostationary satellite systems have the same long delay latency.  iDirect, Hughes HX, ViaSat LinkStar, Gilat, Comtech CDM570 etc all have the same latency, which is the delay due to the distance to the satellite.

If your concern is about very slow speed bit rates then this will be due to congestion and the solution is to pay more for more capacity to be assigned to you.  It costs around $70 per month to provide a dedicated 10kbit/s so don't get your expectations out of line with what you are paying.  In adverts about "up to 1 Mbit/s" note the words "up to".  100 sites sharing perhaps ?  You only get what you pay for.

Resistance to rain is affected by the amount of "rain margin" incorporated in the design.  In the receive direction your dish needs to be large enough to work well during rain.  In the transmit direction your transmitter (BUC) power is normally operating quite low (e.g. 0.5 watt)  but is increased automatically during rain (e.g. 2 watt) to keep the level into the satellite the same.

The least cost satellite systems involve remote sites all sharing same satellite capacity and working via some large teleport dish hub.  Such star networks are primarily suited to email and access to web sites.  Your site transmits an occasional packet whenever you click the mouse.  Customers should expect congestion and slow bit rates from time to time.  If you need phone calls or large file transfers then this represents a heavy traffic demand and you need to choose a high tariff on a shared system or dedicated system.

Regarding VPN, this needs careful design consideration and you need to discuss this with possible providers.  I would suggest implementing a simple (true) private satellite network with all your sites using a private IP address range.  If you need VPN access to an HQ in the US or Europe then this could start at the teleport hub.

Please will others also add their advice and experiences here...

Best regards, Eric.
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Ex Member
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Reply #2 - Jan 15th, 2009 at 1:29pm  
+1 to Eric.

Eddy, answering your 3rd and 4th questions:

iDirect is definitely one of the most advanced VSAT platforms on the market today. There are other modems offering the same all-in-one box approach such as ViaSat LinkStar, many Gilat products, Hughes, however I personally enjoy working with iDirect modems more than anything else. I would describe the current iDirect Infiniti series modems as low to mid range oriented product as, for example, a 5000 series modem сan support fairly large dedicated CIR bandwidth links that would be enough to power a few hundreds of subscribers with ease. It also has an IP router (means Ethernet interface on your end), QoS, acceleration and compression built  in - you'd need to add lots of extra equipment to achieve the same functionality with, say, a traditional SCPC modem such as CDM-570L. What also has to be said is that iDirect runs the best TDMA uplink technology (D-TDMA) on the market today. D-TDMA is a proprietary iDirect's development and is not available with other vendors. Main benefits of D-TDMA is the ability to allocate true CIR and support full-featured QoS. This all helps to achieve a better broadband experience as well as support services like VoIP or videoconferencing with toll free quality.

From a service quality perspective, there is little difference between different satellites. Treat satellite spacecrafts like "dumb" mirrors reflecting radio signals. Of course it is much more complex than that, however as far as we talk about satellite names without going into link budget calculations satellites remain just signal mirrors in such a context. What is important is the way a particular network operator works with the available space segment on satellite: how much rain fade margin is incorporated in the link budget, whether they have a redundant transmitting equipment on Earth or not, what are the carrier sizes, if CIR is configured into service, how far the service is oversubscribed, if QoS is setup properly to prevent malicious traffic, etc. The number of factors hidden is so big it makes difficult to compare different services in a simple manner.

Keys to find a good Internet service:

1) Check if provider offers a good SLA, if they guarantee any uptime, CIR bandwidth level, RTT, etc, with a clear easy to understand refund policy.

2) Provider has to work with you on all the VPN details. For example IPSec VPNs need a pre-accelerating appliance installed at both sides to be able to overcome satellite latency issues. As IPSec encrypts TCP header, modem's built-in TCP acceleration is not working anymore, so you're stuck with 70-90 kbit/s limit per each session no matter how much satellite badnwidth you buy. SSL-VPNs do not require that as TCP header remains intact. As Eric said, VPN over satellite needs careful design consideration.

3) Cost. Beware of too cheap services. Good rule is you get what you pay for. If the service is much cheaper than average then beware of traffic limits, FAPs, poor uptime, poor technical support, etc. As space segment costs are more or less the same, there's no way to offer a substantially cheaper service without cutting corners. It does not mean all expensive services are good though.

Hope this helps.
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Ex Member
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Reply #3 - Jan 19th, 2009 at 4:47am  
Hi,
Thank you for the help so far. It looks like I need to do further homework.
Kind Regards,
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