Cambium Networks PMP 450 AP, Configuration Manual

Page: 103 / 649

Chapter 1: Configuration General configuration
Page
1-75
Translation Bridging Optionally, you can configure the AP to change the source MAC address in
every packet it receives from its SMs to the MAC address of the SM that
bridged the packet, before forwarding the packet toward the public
network. If you do, then:
Not more than 128 IP devices at any time are valid to send data to the AP
from behind the SM.
SM populates the Translation Table tab of its Statistics web page, displaying
the MAC address and IP address of all the valid connected devices.
Each entry in the Translation Table is associated with the number of minutes
that have elapsed since the last packet transfer between the connected
device and the SM.
If 128 are connected and another attempts to connect:
If no Translation Table entry is older than 255 minutes, the attempt is
ignored.
If an entry is older than 255 minutes, the oldest entry is removed and the
attempt is successful.
The Send Untranslated ARP parameter in the General tab of the
Configuration page can be:
Disabled, so that the AP overwrites the MAC address in Address Resolution
Protocol (ARP) packets before forwarding them.
Enabled, so that the AP forwards ARP packets regardless of whether it has
overwritten the MAC address.
When this feature is disabled, the setting of the Send Untranslated ARP
parameter has no effect, because all packets are forwarded untranslated
(with the source MAC address intact).
Send Untranslated
ARP If the Translation Bridging parameter is set to Enabled, then the Send
Untranslated ARP parameter can be:
Disabled - so that the AP will overwrite the MAC address in Address
Resolution Protocol (ARP) packets before forwarding them.
Enabled - so that the AP will forward ARP packets regardless of whether it
has overwritten the MAC address.
If the Translation Bridging parameter is set to Disabled, then the Send
Untranslated ARP parameter has no effect.
SM Isolation Prevent or allow SM-to-SM communication by selecting from the following
drop-down menu items:
Disable SM Isolation (the default selection). This allows full communication
between SMs.
Block SM Packets from being forwarded - This prevents both
multicast/broadcast and unicast SM-to-SM communication.