Infinet Wireless: Technical Documentation
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Unicast-flood" is a phenomenon which occurs  occurs when the frameunicast frame's destination MAC-address is unknown for the switch (not included in its address tablerouting table), the unit it sends this frame to all interfaces of the network, except for the besides the sender interface. The most common reasons of unicast-flood are:

  • MAC address table overflow (a common problem in large networks);
  • Hosts with ARP timers greater longer than the ARP cache timeout;time on switches
  • Incorrect STP settings;
  • Incorrect switch groups settings (in particular, when the numbers IDs of switch groups for the receiving and sending traffic are different).

The unicast-flood process on

...

devices is the following: if the frame's destination MAC-address is not included in the

...

unit's MAC switch forwarding table, then this frame is

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flooded to all interfaces besides the sender interface. The distribution occurs until the

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unit receives a frame with this MAC-address as the sender (i.e., the interface to which the

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frame was destinated to respond). After that, the

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device will learn:

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it will add this MAC address to the MAC switch

...

forwarding table

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 and map it with the interface from which it was received. If the

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device does not learn in 4 seconds, and frames still arrive, then traffic to this direction will be blocked for 4 seconds. Then the process repeats.

This process has the following representation in the unit's interfaces and links graphs:

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titleFigure - Unicast-flood example in the unit's interfaces graphicsgraphs

Also, unicast-flooding can be detected in the "Switch Statistics" → "Device Status" tab in "Flood" column:

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titleFigure - Unicast-flood detection in switch statistics

InfiNet Infinet Wireless units provide unicast-flood protection. If necessary, you can allow unlimited unicast-flood without protection filter filter through the switch group by setting the check box in "Basic Settings" → "MAC Switch settingsSwitch" settings:

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titleFigure - How to allow unicast-flood without protection filter

R5000 units Devices react to unidirectional traffic (which is not a unicast-flood) in a similar manner. This happens, for example, in case of generating "artificial" traffic (using specialized units or software) or when the real traffic is unidirectional. In these cases, it is recommended to allow unlimited unicast-flood  through the switch group without protection filter.