Echelon ISI - Manual (Page 24)

ISI Programmer’s Guide 22
not the domain address server. This method allows the device to make
intelligent decisions about retries, preventing enrollment during the
domain acquisition. It also allows the device to increase automatic
enrollment performance following the completion of domain acquisition.
3. A domain address server can assign a domain to a device without a
request from the device. This minimizes the code required in the device,
and can be used with all devices. This process is called
fetching a device .
4. A domain address server can fetch the domain from any of the devices in
a network and assign it to itself. This keeps multiple domain address
servers in a network synchronized with each other, or allows a
replacement domain address server to join an existing ISI network. This
process is called fetching a domain .
A domain address server must support both methods 2, 3 and 4. It can allow a
device that supports domain acquisition to acquire a domain, it can fetch any ISI
device, and it can fetch a domain from another device.
A domain address server can fetch a domain from any device in the network to be
joined. To install a replacement domain address server, or to install redundant
domain address servers into an existing, previously configured, network, each
domain address server can query the current domain configuration from any
previously configured device in the network. This is called fetching a domain ,
and this process is typically initiated by the user via the newly installed domain
address server.
The following table summarizes the first three procedures:
Acquire Domain Fetch Device Fetch Domain
Description Devices that
support domain
acquisition use
this procedure to
obtain a unique
domain address
from a domain
address server
A domain address
server assigns a
unique domain
address to an ISI
device
A domain address
server acquires the
domain from
another previously
installed device in
the network
Initiated on Device after
enabling device
acquisition on
the domain
address server
Domain address
server Domain address
server
Code required On device and on
domain address
server
On domain address
server On domain address
server