23.1.9 Notes

(1) Coexistence with other functions

(2) About MAC address-learning and ARP,NDP

Because the Switch requires that NextHop MAC addresses resolved using ARP or NDP in Layer 3 forwarding be registered in the MAC address table, keep the following in mind:

• When MAC address learning information is cleared by a command or aging, any ARP or NDP information for the MAC addresses is also cleared. Cleared ARP and NDP entries can be re-resolved by communication if necessary.

• When the aging time for MAC address learning is shorter than the ARP or NDP aging time, the corresponding ARP and NDP entries are cleared by the aging for MAC address learning. This situation can be avoided by setting the aging time for MAC address learning so that it is longer than or equal to the ARP or NDP aging time.

(3) Understanding MAC Address-Learning Movement Detections

• If the source MAC address of the frame received at VLAN where IP address is set is the same as MAC address of the local device, MAC address is assumed to have moved, and the number of moves is counted up.

• If a MAC address is statically registered and the specified MAC address is learned from a port other than the specified port, MAC address is assumed to have moved, and the number of moves is counted up.

(4) About suppressing MAC address-learning

A VLAN for which MAC addresslearning suppression is set cannot be used as Layer 3 interfaces.

(5) About MAC address-learning movement monitoring function

• If CPU is queued with a large number of incoming packets, it may not be possible to detect a MAC address-learn move.

• If MAC address learning moves in three or more locations at the same time, the movement of MAC address learning may not be detected.

• If auto-recovery is specified for a port that is part of a channel group, all ports that are part of the channel group, including ports that were placed in inactive status other than this function, are placed in active status.

• If you configure a channel group on a port with a different member switch, and you configure a port whose MAC address learn count exceeds the threshold, all ports that comprise the channel group on one member switch are placed in inactive status. Even if auto-recovery is specified, all ports that comprise the channel group on the same member switch are placed in active status. The following figure shows inactive status for this configuration.

  Figure 23-1: Example of changing the port status using MAC address learning movement monitoring facility in a link aggregation configuration that connects multiple member switches

  1. The number of moves for MAC address-learning is exceeded for the ports that constitute the channel group on the master switch side of the Switch.

  2. Inactive all ports on the master switch side of the channel group including the applicable ports. The ports on the backup switch are not put into inactive.

• If the port state transitions to the line test state during the period between the port being in inactive state and the automatic recovery state, and the port is in the automatic recovery time during the line test state, the port remains in inactive state even if the line test state ends. If the line test status is completed before the automatic recovery, it will be automatically restored and the port will be in active status.