In computing, LBX, or Low Bandwidth X, was a protocol to use the X Window System over network links with low bandwidth and high latency. It was introduced in X11R6.3 ("Broadway") in 1996, but never achieved wide use.
X was originally implemented for use with the server and client on the same machine or the same local area network. By 1996, the Internet was becoming popular, and X's performance over narrow, slow links was problematic.
LBX ran as a proxy server (lbxproxy). It cached commonly used information — connection setup, large window properties, font metrics, keymaps and so on — and compressed data transmission over the network link.
LBX was never widely deployed as it did not offer significant speed improvements. The slow links it was introduced to help were typically insecure, and X tunneled over a secure shell connection — which includes compression by default — proved faster than LBX. Finally, it was shown that greater speed improvements to X could be obtained for all networked environments with care and attention to application design.
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