Description: This object is used to control whether the repeater will allow completion of training by end-nodes using null MAC addresses. The 802.12 standard is written to disallow such training. However, some end-nodes may use this configuration at power-up before any software is loaded. If so, the user may see frequent training occurring on the repeater because of this. In addition, some end-node applications may not work when initial training fails due to the locking out of null MAC addresses.

The default setting of this object is to allow null MAC addresses to train. This is recommended for most situations, despite the fact that it contradicts the 802.12 standard.

For repeaters that have First Learned address security on this hub, disallowing null-address training provides the most extensive security until the ports' authorized addresses are learned. However, if this creates problems for the end-node applications, it may be necessary to instead explicitly assign the ports' authorized addresses and configure this object to allow null-address training.