Internet Protocol Enhanced Over Satellite Networks

Extensive research conducted by the Satellite Networks and Architectures Branch of the NASA Lewis Research Center led to an experimental change to the Internet's Transmission Control Protocol (TCP) that will increase performance over satellite channels. The change raises the size of the initial burst of data TCP can send from 1 packet to 4 packets or roughly 4 kilobytes (kB), whichever is less.

TCP is used daily by everyone on the Internet for e-mail and World Wide Web access, as well as other services. TCP is one of the feature protocols used in computer communications for reliable data delivery and file transfer. Increasing TCP's initial data burst from the previously specified single segment to approximately 4 kB may improve data transfer rates by up to 27 percent for very small files. This is significant because most file transfers in wide-area networks today are small files, 4 kilobytes or less. In addition, because data transfers over geostationary satellites can take 5 to 20 times longer than over typical terrestrial connections, increasing the initial burst of data that can be sent is extremely important.

This research along with research from other institutions has led to the release of two new Request for Comments (RFC, ref. 1) from the Internet Engineering Task Force (IETF, the international body that sets Internet standards). In addition, two studies of the implications of this mechanism were also funded by NASA Lewis (refs. 2 and 3). Additional information is available in reference 4.

Find out more about this research:
rfc2414.txt and rfc2416.txt (external site)

References

1. Allman, M.; Floyd, S.; and Partridge, C.: Increasing TCP's Initial Window. RFC 2414, Experimental, Sept. 1998.
2. Shepard, T.; and Partridge, C.: When TCP Starts Up With Four Packets Into Only Three Buffers. RFC 2416, Informational, BBN Technologies, Sept. 1998.
3. Allman, M.; Hayes, C.; and Ostermann, S.: An Evaluation of TCP With Larger Initial Windows. ACM SIGCOMM, vol. 28, no. 3, 1998, pp. 41-52.

Lewis contact: William D. Ivancic, (216) 433-3494, William.D.Ivancic@grc.nasa.gov
Author: William D. Ivancic
Headquarters program office: OSS, OAT
Programs/Projects: Level 1 HEDS 22 improved ground-based data networks, 64 advanced data handling; ESE 119 advanced end-to-end mission information system technologies; Level 2 3694 desktop instrument operations end-to-end protocol standards, 3700 and 2030 high- data-rate communications, 3753 communications protocols; SOMO Interoperability and Standardization 8, 9, 10; Innovative Mission Information Systems 56; and Hybrid Network Ubiquity 61, 62, 63

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