Editing NX technology (section)

== Legacy technology ==
NX [[Data compression|compresses]] the X11 data to minimize the amount of data transmitted, and [[Cache (computing)|caches]] data to keep the session as responsive as possible. For example, the first time a menu is opened, it may take a few seconds, but is subsequently almost instant.

NX is faster than its predecessors, as it eliminates most of the X [[Round-trip delay time|round trips]], while dxpc and MLView only compress data. The two principal components of NX are '''nxproxy''' and '''nxagent'''. nxproxy is derived from [[dxpc]] and is started on both the remote (client in X terminology) and local (server in X terminology) machines, simulating an X server on the client and forwarding remote X protocol requests to the local X server.

Simplest setup:<ref name="NX build">{{cite web |url= https://www.nomachine.com/DT12I00020|title= Building and using NX components |publisher=NoMachine |date=2015-05-22 |access-date= 2015-08-21}}</ref>

 remote clients (xterm, etc.)
             ↕
       nxproxy client
             ↕
          Network
             ↕
       nxproxy server
             ↕
 local X server (monitor/keyboard)

'''nxproxy''' alone achieves 1:10 to 1:1000 compression ratios,<ref>{{Citation | publisher = NoMachine | url = http://www.nomachine.com/documentation/building-components.php | title = Building and using NX components}}.</ref> reducing bandwidth, but does not eliminate most of X's synchronous round trips, responsible for most of X's perceived latency.

'''nxagent''', derived from Xnest (similar to [[Xephyr]]), is typically started on the remote (client) machine, thus avoiding most X11 protocol round trips. Together with nxproxy (built into nxagent), this setup performs well over low-bandwidth and high-latency links.

Typical setup:<ref name="NX build"/>

  remote clients (xterm, etc.)
             ↕
   nxagent server side \
   nxagent client side   nxagent executable
      nxproxy client   /
             ↕
          Network
             ↕
       nxproxy server
             ↕
 local X server (monitor/keyboard)

On systems with a functional X11 implementation, nxproxy and nxagent are all that is needed to establish a connection with low-bandwidth requirements between a set of remote X clients and the local X server. SSH can be used to establish a secure tunnel between the hosts. NX 3 relies on SSH functionalities and existing open-source SSH software, making it possible to run contemporary Unix and Windows desktops and arbitrary network applications over the Internet in a secured and controlled way.

FreeNX and the various NX Clients are used for setup, handling suspend and resume, secure tunnelling over SSH, and printing and sound.