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XLR 64 bit Addressing - Ethernet RF Bridging

The purpose of Ethernet RF bridging is to act as an Ethernet cable replacement. The MAC/PHY layer
of the Ethernet standard handles all Ethernet traffic. As a result, the XLR PRO does not have to have a
valid IP address on the network for bridging to work.  If the XLR PRO receives an Ethernet packet with a MAC address that does not match its own MAC
address, and if you enable Ethernet bridging, then the entire Ethernet packet is encapsulated inside
of a radio frame and sent over the air (OTA) to another XLR PRO.
The XLR PRO does not support fragmentation, so the unit sends the entire Ethernet packet in one
OTA frame. This can cause an issue at lower data rates. If the RF data rate (BR) is less than 3 (141kb/s),
then full size Ethernet frames cannot be transmitted. However, smaller frames can be transmitted at
lower data rates. We do not recommend this for typical Ethernet applications, but you could use it in
some scenarios.

64-bit addresses
Each radio has a unique factory-assigned IEEE 64-bit address. You can read the factory-assigned
address with the SH and SL commands. Addresses use the following form: 0x0013A2XXXXXXXXXX.
The first six digits are the Digi Organizationally Unique Identifier (OUI). The broadcast address is
0x000000000000FFFF.

Unicast
To transmit to a specific radio:
• For Ethernet RF bridging, set BA to the SH:SL of the destination radio. BA is the entire 64-bit
address and is not broken into two 32-bit values. For example: BA=0x0013A20012345678.
• If you have configured Ethernet bridging for unicasts, up to three retries occur while waiting for an
ACK. As a result, unicasts are slower, but more reliable than broadcasts.

Broadcast
To transmit to all radios:
• For Ethernet RF Bridging, set BA to 0x000000000000FFFF.
• If more than two XLR PRO devices are participating in a bridge, then you must set BA to 0xFFFF.
• By default, Ethernet bridging uses broadcasts and no retransmissions occur. If you send packets
via TCP, then the TCP protocol provides the retransmissions as needed to provide for reliability.
UDP packets may be lost when BA is set to a broadcast address.
Last updated: Aug 23, 2017

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