Echelon LNS - Manual (Page 284)

LNS Programmer's Guide 270
Most standard network interfaces can only support a single outstanding transaction at a
time. This means that in order to poll 2 network variables, the first poll must be
completed before the second can start. Note that unlike most other standard network
interfaces, an i .LON 100 Internet Server can support up to 15 simultaneous subnet/node
or group addressed transactions.
Number of Groups
When using a high performance network interface, a Network Service Device can be a
member of up to 256 LonTalk groups, which is the LonTalk group limit per network.
When using a standard network interface, a Network Service Device can be a member of
no more than 15 groups, because each group must be configured in a standard network
interface’s address table entry, and the interface is limited to 15 address table entries.
Supporting Multiple Networks
Each Network Service Device in an LNS network must have a unique Neuron ID and
domain/subnet/node address. Standard network interfaces support only a single Neuron
ID, and thus can only support a single Network Service Device in a single LNS network
at any given time. When using a high performance network interface, all addresses,
including the Neuron ID, are stored on the PC containing the network interface.
Therefore, a single high performance network interface can be used to support multiple
Network Service Devices in multiple networks.
A L ON W ORKS /IP Interface used to access a L ON W ORKS /IP channel must use a unique IP
address and IP port combination. This allows multiple L ON W ORKS /IP Interfaces to exist
on a single PC with a single IP network card. This in turn allows a single PC to have a
L ON W ORKS /IP Interface device for every L ON W ORKS /IP Channel it needs to access.
Neuron Ids
When operating as a standard network interface, each network interface has a unique
Neuron ID, which is stored in the network interface hardware. Thus, if a Network
Service Device is using a standard network interface, the Neuron ID assigned to its
network interface will only change when a new network interface is installed and
selected as the active network interface.
However, you should be aware that the Neuron ID for a high performance network
interface is not stored in the network interface hardware. Instead, LNS generates a
separate Neuron ID for each Network Service Device using the network interface, and
associates that Neuron ID with the Network Service Device.
This process could result in creating duplicate Neuron IDs (duplicates of other Network
Service Devices using high performance interfaces). However, the chances of generating
duplicate Neuron IDs in the same network are statistically miniscule. The Neuron ID
assigned to each Network Service Device using a high performance network interface is
stored in the Windows Registry of the PC running the LNS application. Usually, the
same Neuron ID will be used each time that Network Service Device is opened. However,
the Neuron ID is not backed up, since this would produce duplicate Neuron IDs. As a
result, moving a network from one PC to another (i.e. copying a network database and
moving it to another machine), or performing a network recovery with a client using a
high performance network interface, will result in generating a new Neuron ID for the
network interface.