Ethernet Switch Information - Constraints

The Sun Ray ultra-thin client is designed to work well with any standard Ethernet switch and works with either Level 2 or Level 3 switching support.

The application of Ethernet switches in this environment differs from normal computer-to-computer communications in that the switches are used as an Input/Output connection where the network behavior is potentially visible to the end user. In very poorly implemented interconnects, the lack of network performance may be seen by the user as a fault of the Sun Ray Ultra-Thin Client.

In the rare case that a switch did not test satisfactorily within the Sun Ray Ultra-Thin Client environment, it could be traced back to one of the following issues:

The Sun Ray Ultra-Thin Client contains no internal state, so it cannot be configured for a specific Ethernet interface setting -- it relies on auto-negotiation.

With a small number of switching products, there have been mismatches in the results of auto-negotiation, from complete failure to operate to negotiation of operation at less than the maximum possible. This is easily tested by simply connecting the Sun Ray Ultra-Thin Client to the switch and observing the results of the connection. Testing more times with more clients will give a greater degree of confidence.

The Sun Ray Ultra-Thin Client is designed to power on and be fully operational in a very short time -- typically less than 10 seconds.

Experience has shown that some switches have initial configurations that cause this turn-on time to be considerably longer, often taking 30 seconds or longer to achieve full working state. Longer turn-on times typically are due to configuration of the Ethernet switch to implement capabilities not needed in the Sun Ray thin client environment. The most common of these capabilities is enabling Spanning Tree protocols, which are designed to detect and compensate for loops in the connection between switches. Spanning Tree should be disabled or deferred for Sun Ray ultra-thin client operation.

If Spanning Tree is disabled and the turn-on time is still excessive, it may be necessary to contact the switch manufacturer to determine if there are other features and/or proprietary protocols interfering with the Sun Ray Ultra-Thin Client. Some switches may have features designed into the switch that cannot be changed; if this is the case, then it may not be possible to reduce the turn-on time.

In a heterogeneous switching environment, all switches in the VLAN network should be compliant with IEEE 802.1Q and implement the IEEE 802.3a frame extensions to prevent Ethernet packets larger than the current IEEE 802.3 maximum of 1518 bytes being discarded.