Subject: Software

From: "sbucca" <[email-masked]>
Date: Wed, 19 Jan 2000 09:25:01 -0700

Dear all,
	Our company is looking for software which transparently resides on top of
the TCP/IP stack to enhance its performance over satellite links.
Information on commercially available software and companies who would be
receptive to writing custom software would be greatly appreciated.  Thank
you.

Steve Bucca
Codespace, Inc.
[email-masked]

---

From: [email-masked] (Keith Scott)
Date: Wed, 19 Jan 2000 12:38:41 -0500

Mr. Bucca,

MITRE has developed a set of extensions to TCP (called SCPS, see below and 
http://www.scps.org ) that can greatly enhance performance in stressed 
environments exhibiting one or more of the following characteristics:
         Highly asymmetric bandwidth allocation
         Large delays
         Link outages
         A high degree of corruption-related loss

We have a reference implementation of the SCPS stack and a transparent 
gateway application that will translate between TCP with and without the 
SCPS performance-enhancing options.  This means that you can run SCPS over 
the satellite link while preserving compatibility (and congestion control!) 
on the ground portions of your network.  All of this is available as source 
code, free of charge, to most US companies.  I'm not entirely sure, but as 
I understand it, if you then use the code to make a product, you're free to 
sell it with no interference from us (and no royalties, etc.).  Check this 
last with the appropriate lawyers.

The rest of this message is extracted from our IANA request for the various 
TCP option numbers.

This research began as part of the Space Communications Protocol 
Specification (SCPS) work, however we believe that the options developed 
have wider, more general-purpose applicability.

The four TCP options for which we are requesting assignment of option 
numbers are:
    * SCPS-capabilities option.  This option allows endpoints to 
agree/decline to use the following TCP extensions: Partial Reliability 
Transport Service (PARTS, a set of extensions for TCP), Selective Negative 
Acknowledgments (SNACK), loss-tolerant header compression, and 
network-layer timestamps.
    * Selective Negative Acknowledgments (SNACK) option.  This option is 
set on ACK segments to indicate the presence and location(s) of holes in 
the receiver's out-of-sequence queue.
    * Record boundaries option.  This option is set on data packets 
containing bytes that have been logically marked as being record boundaries.
    * Corruption experienced option.  This option can exist on both data 
and ACK packets to indicate that a link in a path is experiencing corruption.

The attached pdf file contains a description of the options.  If you have 
any questions or comments, please feel free to contact me:

         Keith Scott
         mailto://[email-masked]
         (703) 883-6547

                 --keith