The LBX mini-HOWTO

11. Alternatives

If you don't like lbxproxy for some reason: you're not satisfied with the performance, it doesn't work for you, you don't want to hassle with creating an lbxproxy for the remote host, or you simply are interested in trying other options, there is at least one other package for X protocol compression (anyone have others?)

11.1 dxpc - The Differential X Protocol Compressor

• Original Author: Brian Pane <brianp at cnet.com>
• Current Maintainer: Zachary Vonler <lightborn at mail.utexas.edu>

dxpc works in essentially the same way as LBX. However, to avoid having to implement an X extension and modify the X server code, dxpc uses two proxies: one that runs on the REMOTE host, like lbxproxy, and one that runs on the LOCAL host.

The REMOTE host proxy communicates between the X clients and the LOCAL host proxy, and the LOCAL host proxy communicates between the X server and the REMOTE host proxy.

So, to both the X clients and the X server, it looks like X protocol as usual.

Advantages

• Since it's a completely separate application that does not require any X internals, it's much simpler to compile and install.
• It's maintained separately, so you don't have to wait for the OSF to release new X versions for enhancements or fixes.
• It provides more and better compression information and statistics than lbxproxy.

Disadvantages

• It is not a standard part of X; you must obtain and build it separately.
• It is slightly more complex to set up, since it requires a LOCAL-side proxy as well as the REMOTE proxy.

Where Can I Get dxpc?

The source for dxpc is available at ftp.x.org.

There is a WWW homepage for dxpc that gives a lot of good information, including pointers to the dxpc mailing list, access to the source code, and a number of pre-built binaries for various platforms:

http://ccwf.cc.utexas.edu/~zvonler/dxpc/

11.2 Ssh (Secure Shell)

Ken Chase <lbxhowto at sizone.org> notes that ssh can be used for compression. Although its main purpose is to provide security, it also compresses the data it sends.

Thus, if you run X over a ssh link you will automatically obtain some amount of compression.

11.3 Which Is Better?

I don't know. Both LBX and dxpc are certainly better at raw compression than ssh. Of course, ssh provides the added advantage of security. And of course, there's no reason you can't use both ssh and one of the other two, to get good compression and security.

It shouldn't be hard to run some benchmarking against these options and get both subjective and statistical measurings of performance. But I haven't done this, and I don't know of anyone who has.