LBI-38962
8
USING NETWORK LAYER RDTS
If Network Layer Radio Data Terminals (RDTs) are being used, i.e. RDTs with the EDACS Network Driver
(END) installed, all message source and destination references are to IP addresses. EDACS addresses are not
important or relevant to either the IP host or RDT, and are effectively hidden. This is analagous to an ethernet
network, where an ethernet address is assigned to all devices, but the user need not know this address to
communicate with other devices on the network - a higher layer addressing scheme such as IP is utilized.
NOTE
The mapping of LIDs to IP addresses is static. If a radio's LID is changed,
a new IP address will be associated with that radio. To keep the same IP
address, the mapping must be modified in the EDG SYSTEM.TXT file.
Host A
CAP
Host B
Host Network
Internal EDG Network
TSI
EDACS Network
EDG
1.0.15.12
1.0.15.13
1.0.0.0
199.0.0.0
128.1.0.0
Radio/RDI/RDT
128.1.0.64
128.1.64.2
Radio/RDI/RDT
128.1.0.65
128.1.64.1
Radio/RDI/RDT
128.1.0.66
128.1.64.1
1.0.15.14
An IP host internet, using all Network Layer RDTs, with addresses assigned
Notice that each radio/RDI/RDT has two IP addresses associated with it, a unit address and a group address. The
unit address is unique to every radio in the system. Host originated data calls to this address will be received by a
single radio only. The group address is shared by more than one radio. Host originated data calls to this address
may be received by a large number of radios at the same time.
For radio originated data calls, the destination address is also an IP address, whether that of a host, another radio,
or a group of radios. The EDACS Network Driver takes care of the underlying EDACS addressing.
In a more complex configuration, there could be multiple gateways between the EDG and the Hosts. Regardless
of the configuration, the EDG CAP Board's external IP Address must be a valid address on the network that it is
connected to. Routing table entries would be used to allow the EDG and Hosts to communicate.