Appliance Link Protocol

The Appliance Link Protocol (ALP) is used by Sun Ray ultra thin clients to talk to Sun Ray servers. The closed source implementation of the Sun Ray Server Software (srss) is developed and distributed by Sun Microsystems. The software bundle is often referred to as SRS (Sun Ray Software).

ALP consists of several components:

Session Protocol (ALSP)
Client -> Server TCP port 7009
ASCII/text based
Render Protocol (ALRP)
GFX: Server UDP port g <-> Client UDP port c
AUDIO: Server UDP port a <-> Client UDP port c
random ports (g, a, c); binary protocol
The client tells the server via the Session Protocol which UDP port (c) to use.
A different set of packet sequence numbers are used for the GFX and AUDIO commands.
Device Protocol (ALDP)
Client -> Server TCP port 7011

The protocol can be seen with a network scanner, if the ray server and client are communicating unencrypted (man utpolicy).

Look at SoftRay for an open (work in progress) implementation in Java. Details about ALP can be found there as well.

Sun has released a (closed source) client in SRS5 (Sun Ray Software 5: srss-4.2 / srwc-2.2). Suns client is limited to connect from Windows and Mac OS X (can work from Linux via Wine) to a SRS5 server only.

See also