Serial Port Specifications
Serial Topologies
WaveLAN/EC-S User’s Guide
5-7
sender to retry. This guarantees the receiving device only receives
error-free transmissions.
Broadcast Topology
5
Unlike with Station-to-Station configurations, after the WaveLAN/
EC-S WaveLAN/EC-Sends a packet, it does not wait for an
acknowledgment. Broadcast mode is an unacknowledged service
for two reasons:
1.
The broadcasting device doesn’t know who is going to be
receiving the data, and
2.
Even if it did know the receiver, it can be extremely inefficient
to have every device acknowledge a message once the packet
is received.
Since broadcasts are unacknowledged, a device cannot retry
transmissions while configured for this topology.
Any WaveLAN/EC-S device that correctly receives the packet
compares the packet's broadcast address to the device's own
broadcast address. If the two addresses match, the device will
extract the message and send it out its serial port. This guarantees
that the user devices only receive error-free transmissions.
NOTE:
Since broadcasting is an unacknowledged service, if a
message was lost or damaged, the message will not get
through. Therefore, the user devices should contain
software to perform message retransmissions should this
be necessary. In most cases, devices that use wired
networks already contain this software.
