SeaNet
faqs
general faqs


General FAQs
  1. What's an SCN?
  2. What are the typical operations available for the SCN?
  3. How does BatchXFR work?
  4. What are DataPipes?
  5. How does Interactive IP work?
  6. How does WebMirroring work?
  7. How do I get an Interactive IP User Account?
  8. How do I get a DataPipe established?
  9. Does SeaNet do email?
  10. Who should I contact if I have questions or problems?
  11. Is it more efficient to send larger files or smaller ones?
  12. What level of performance to you get with SeaNet BHSD?
  13. What are the typical costs for BHSD?



  1. What's an SCN?

    SCN stands for the SeaNet Communications Node, the core computer system that interfaces to a variety of wireless communications links. The purpose of the SCN is to provide Internet connectivity for remote research platforms using various of communications links including Inmarsat satellite communications, spread spectrum wireless modems, cellular telephones, etc. There are shipboard SCNs and shore-side NICs that communicate together to provide a wide variety of services. [Back to top]
  2. What are the typical operations available for the SCN?

    There are currently three modes of operations available on the SCN: BatchXFR, Interactive IP, and WebMirroring. Each has tradeoffs between efficiency and flexibility. BatchXFR is the most efficient since it pre-packages all the files before the transfer occurs. On the otherside of the spectrum is the Interactive IP which is the most flexible. With Interactive IP, the ship is directly connected to the Internet allowing users to do web-browsing, video conferencing, chat sessions, etc. [Back to top]
  3. How does BatchXFR work?

    BatchXFR uses the concept of InBox/Outbox queues along with DataPipes (refer to What are DataPipes?) to perform batch file transfer capabilities. During a connection, files in the InBox/OutBox queues are automatically transferred to/from the central SeaNet facility called the Network Information Center (NIC). Transfers to and from the ship occur simultaneously in both directions. After the transfers to the NIC are complete, the link is shutdown. The NIC then distributes any DataPipe files to the appropriate computers on the Internet. This method eliminates any potential Internet latency that may occur while the satellite link is up, thus reducing costs. [Back to top]
  4. What are DataPipes?

    DataPipes use a simple concept of associating a directory on a ship's computer to a directory on a computer on the Internet. DataPipes are one-directional with one directory identified as the input source directory and the other as the output destination. You can define several DataPipes, with some being destined for shore and others defined as incoming DataPipes to the ship. The DataPipes are an efficient mechanism of using the satellite link. [Back to top]
  5. How does Interactive IP work?

    Interactive IP allows authorized users to establish an interactive Internet session. The SCN operator can add interactive users who must provide billing information. The SCN operator will bringup and shutdown all interactive sessions. [Back to top]
  6. How does WebMirroring work?

    The built-in SCN WebMirror system will allow a web site on board ship to be mirrored on shore as well as a web site on-shore back to the ship. The system will only transfer files that have been modified since the last time the system was synchronized. Users can also perform their own web-mirroring with packages such as Front Page. In this case, they manage the web site on board ship and use the Interactive IP session capability to synchronize their web site. [Back to top]
  7. How do I get an Interactive IP User Account?

    Send an email to the SeaNet Operations Manager at seanet-ops@seanet.int. [Back to top]
  8. How do I get a DataPipes established?

    Fill out the DataPipe and Billing information forms available on the Your Cruise     page and then fax them to the SeaNet operations manager. You will need information such as the IP addresses for on shore destination computers and the names of the destination directories. [Back to top]
  9. Does SeaNet do email?

    SeaNet now offers an email package (CMail) as an alternative to existing shipboard email systems. [Back to top]
  10. Who should I contact if I have questions or problems?

    Contact SeaNet Service at SeanetService@seanet.int. SeaNet offers support Monday through Friday, 9-5 EST. [Back to top]
  11. Is it more efficient to send larger files or smaller ones?

    The short answer is that it is more efficient to send larger files than smaller ones. It's also more efficient to do bi-directional transfers as these go simultaneously. With large transfers (> 10 MB), it may make sense to break the files into smaller ones since it requires the link being up for a long while, and something such as a heading change could cause the link to be lost. However, when the link is again established the transfer will start where it had been lost. Note: We have successfully transferred a 22 MB file. [Back to top]
  12. What level of performance to you get with SeaNet BHSD?

    We're still studying the statistics, but the efficiency increases with larger files. On average for files > 200K, the average transfer rate is between 3500-6100KBytes/Sec for compressed data. Note however, that rates can vary substantially. [Back to top]
  13. What are the typical costs for BHSD?

    These vary for different carriers (Comsat/Station 12) and there are peak and off-peak rates. Visit the Budget Guidelines page for more details.

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