Compressing your email, saving $:
the UUPlus approach

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Posted: 2/8/2006

If you depend upon remote satellite or HF radio services for your email, you may have heard of "compression" and asked: how does it work, and how does it help?

An increasing number of HumaniNet field partners are using the UUPlus email service for controlling costs and improving reliability.  Their service achieves up to 75% compression of text and most attached files, thus reducing the cost of email over satellite significantly.

As a rule of thumb, if your monthly airtime costs for data are over $50, you should consider UUPlus or a comparable service.  For example, if you pay $1.50/minute for airtime (data) and your statement shows 40 minutes,  that is $60 of usage.  With UUPlus service compressing by 75%, your airtime would be around 10 minutes, resulting in usage costs of $15 for airtime and $35 for the UUPlus service = $50, or a savings of $10.

We have asked Jeremy Bonnett, business manager at UUPlus, to explain their service, which is especially popular with remote users who send and receive email over Iridium, Thuraya, and RBGAN.  For more information, contact Jeremy at and mention this article.

UUPlus Email software provides a full featured email distribution solution for exchanging Internet mail and data files over virtually any available data capable connection. Though UUPlus is highly configurable and versatile enough to meet the demands of data communications in infrastructure challenged areas, the software presents both administrators and users with friendly, easy to use configuration and operational interfaces. As well as being able to function as a stand-alone system, UUPlus is designed to seamlessly plug into any existing email network to provide secure email access beyond the reach of traditional email systems.

UUPlus supports all major satellite networks including: Inmarsat RBGAN and other services, Iridium, Thuraya, Globalstar, Mobile Satellite Ventures, Optus Mobile Sat, and ACeS.  In addition, UUPlus supports:

  • Standard PSTN land lines (conventional telephone "dialup")
  • GSM, CDMA, and GPRS mobile phones
  • Codan, Pactor III, and HAL HF modems
  • IP based data networks including VSAT, MPDS, leased line, local ISP dialup, and broadband.

When sending mail over any connection type, UUPlus batches, compresses, and encrypts the data to make the transfer secure and the transfer size as small as possible. Typically non uniform text will compress by a ration of 4:1. Any attachments associated with email messages are removed from the message prior to the batching process, saved into their native format and compressed. By eliminating the MIME encoding necessary to place a binary file in an ASCII file, we reduce the transmission size of that email by one-third. Compression on message attachments is highly dependent on the type of file. Image file types such as GIF, and JPEG have their own compression algorithms and do not compress much if at all.  Microsoft Word and Excel files can potentially compress up to 12:1.

A bi-directional, error and latency tolerant variant of the UUCP transport protocol is used. Unlike TCP/IP, which requires a relatively high bandwidth, low latency, and error free connection, UUPlus' protocol is largely unaffected by the speed or latency of the connection, and will tolerate an error rate of up to 30% packet loss. When using IP based connections the same batching, compression and encryption is used. Rather than using a lock-step, chatty, uncompressed protocol such as POP or SMTP with SSL or TLS encryption, UUPlus encrypts at the file level to greatly reduce the overhead required for a secure connection. Even when used over high speed VSAT connections, UUPlus was able to connect during low bandwidth availability times when POP, SMTP, and Web based protocols failed.

UUPlus offers a Satellite Email Service with the UUPlus software or licenses the software for use in private networks. The United Nations World Food Programme uses UUPlus software as an integral link in their Deep Field Messaging System. The governments of Morocco, Nigeria, and Afghanistan use UUPlus software in their HF data links. Numerous NGOs such as Médecins Sans Frontières, Merlin, New Tribes Mission, and Wildlife Conservation Society use UUPlus software for their HF and Satellite email needs.

For further information and assistance, contact us at

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