LocalTalk: 32-Device Limit Is a Recommendation

The 32-node limit for LocalTalk is a recommendation. It is specific to AppleTalk networks using LocalTalk cabling scheme. The considerations for this limit is the average traffic generated by these nodes and the physical transmission limitations of LocalTalk, so the 32-node limit is more of a performance limit.

Having more than 32 nodes can have an impact on network performance. Since there are 254 possible node addresses on a LocalTalk network, using all possible node IDs will reduce network performance due to increased traffic.

The node addresses are divided up this way:

1 - 127 are user node IDs
128 - 254 are server node IDs
0 and 255 these two node IDs are reserved

From a traffic standpoint, only active nodes have an effect on performance. In addition, both active and non-active workstations affect the electrical characteristics of the network, because the LocalTalk connector box (transformer isolation) puts a load on the network, regardless of whether the workstation is on.

The document, "Inside AppleTalk", gives detailed technical information about AppleTalk and is available from Addison-Wesley Publishers.