NETGEAR M4350-24F4V 24-Port 10G SFP+ Managed AV Network Switch - Manual (Page 388)

of the same VLAN, just like any other broadcast packet. The packet is not forwarded to
the port from which it was received
If the source MAC address matches the MAC address of the switch, the switch can
perform one of the following actions, depending on how you configure the action:
• The port is shut down.
• A log message is generated. (If a syslog server is configured, the log message can
be sent to the syslog server.)
• The port is shut down and a log message is generated.
Loop protection is not intended for ports that serve as uplinks between spanning
tree–aware switches. It is intended for unmanaged switches that drop spanning tree
BPDUs. Loop protection detects physical and logical loops between Ethernet ports on
a device. You must enable loop protection globally before you can enable and configure
it at the interface level. Loop protection is supported on physical interfaces and static
LAG interfaces, but not on dynamic LAG interfaces.
About loop protection
Loops inside a network are costly because they consume resources and reduce the
performance of the network. Detecting loops manually can be cumbersome.
The switch can automatically identify loops in the network. You can enable loop
protection per port or globally.
If loop protection is enabled, the switch sends predefined protocol data unit (PDU)
packets to a Layer 2 multicast destination address (09:00:09:09:13:A6) on all ports for
which the feature is enabled. You can selectively disable PDU packet transmission for
loop protection on specific ports even while port loop protection is enabled. If the switch
receives a packet with the previously mentioned multicast destination address, the
source MAC address in the packet is compared with the MAC address of the switch. If
the MAC address does not match, the packet is forwarded to all ports that are members
of the same VLAN, just like any other multicast packet. The packet is not forwarded to
the port from which it was received.
If the source MAC address matches the MAC address of the switch, the switch can
perform one of the following actions, depending on how you configure the action:
• The port is shut down.
• A log message is generated. (If a syslog server is configured, the log message can
be sent to the syslog server.)
• The port is shut down and a log message is generated.
If loop protection is disabled, the multicast packet is silently dropped.
Main User Manual 388 Configure Switching Information
Fully Managed Switches M4350 Series Main User Manual