Sun Ray 3.0 introduced some enhancements to the ALP (Appliance Link Protocol) that make Sun Ray thin clients adapt to lower bandwidth scenarios (like connecting to a server on the other side of a WAN link, or through an ADSL line - more about this setup can be found in the Sun Rays at Home white paper).

Last week I did a technology demo at a long time Sun Ray customer who is still using SRSS 2.0 and Solaris 8. I've used my notebook running Nevada build 18 and the SRSS 3.1 public beta (it runs fine - though it's a bit difficult to have the same Solaris instance set up for both SRSS demos and normal office work). Their conclusions were quite interesting:

• they seemed to like JDS
• Hungarian localization of JDS was a great plus (they also made me login with Slovak and Romanian locale, but these weren't completely translated)
• Exchange connectivity of Evolution is something that really started them thinking (some of their thin client users need Citrix licenses only to access Outlook running on a remote Windows Server - obviously there is a chance that utilizing Evolution they would not need to buy additional licenses when the staff grows)

Limiting bandwidth to 512k and showing how audio still worked ("AM radio" quality) while opening windows and browsing directories) was also impressive. It's interesting though how early graphical quality starts to decrease: you don't want to run any application requiring sharp graphics over an 512k link. Gnome terminal really suffered from low bandwidth while xterm and dtterm gives the user much better font quality (obviously gnome-terminal is drawing into offscreen pixmaps to "enhance" performance which in turn decreases it considerably on a Sun Ray remote client).

How to limit the bandwidth of a Sun Ray? There is a DHCP vendor parameter available for some time (I've used it with SRSS 2.0 as well) called NewTBW which can be added to a DHCP macro. The parameter accepts a numeric value which is interpreted as the number of bits allowed to be transmitted in one second to the thin client.

The easiest way to add the parameter to your config is via the GUI DHCP config tool available at /usr/sadm/admin/bin/dhcpmgr. You can also use the CLI:

dhtadm -M -m 192.168.79.0 -e NewTBW=1000000
svcadm restart dhcp-server

Note: low bandwidth is also about latency, so limiting the pipe gives you only one half the impression of a real low bandwidth/WAN setup.

Note2: a bandwidth limit of 1 Mbit/sec was quite acceptable, even with the default JDS look & feel. Medium sized flash animations also worked nice.