Technical information

AX Series L2 Loop Detection Configuration Guide (Edition 2)

(6) When using STP, enable PortFast and the BPDU filter for access ports for which the L2 loop detection setting is enabled

When STP is used for the L2 redundancy protocol, the functionality related to ports on the endpoint side include

PortFast, BPDU guard, and the BPDU filter. If the functionality is used with the L2 loop detection functionality,

ALAXALA Networks Corporation recommends that PortFast and the BPDU filter be enabled.

Enabling PortFast and the BPDU filter disables STP operations on the port, which can prevent interference

between STP and the L2 loop detection functionality.

(7) Set the sending interval of L2 loop detection frames to as small a value as possible.

The period of time from occurrence to detection of an L2 loop is determined by the sending interval of L2 loop

detection frames. So it is preferred to set a value as small as possible, according to the descriptions in 1.4 (4)

Transmission rate and sending interval of L2 loop detection frames in this document. As mentioned in the

descriptions, the sending interval of L2 loop detection frames can be calculated as follows:

<sending-interval-(sec.)> ≥ <number-of-VLAN-ports-subject-to-L2-loop-detection> / <frame-transmission-rate-(pps)>

If calculated taking the above-mentioned configuration as an example,

<sending-interval-(sec.)> ≥ (2 x 1 + 2 x 1 + 15 x 1 + 1 x 3) / 30 = 0.73

From this result, set the L2 loop detection frame sending interval to 1 (sec.) for the above-mentioned configuration.

Recommended value for using STP on

AX2430S (pps)

0/5-6, 0/7-8, 0/9-23: 1 VLAN for each, 0/24: 3 VLANs