3.9.1 L2 Loop Detection

The following table describes the transmission rates of L2 loop detection frames.

Table 3-46 L2 Loop-Detected Frame Transmission Rate
Model	Send rate of L2 loop-detection frames (per switch) #1
Model	When using Spanning Tree Protocols, GSRP, or Ring Protocol	When not using Spanning Tree Protocols, GSRP, or Ring Protocol
All models	30pps (recommended) #2	200pps (Max.) #3

Formula for calculating L2 loop detection frame transmission rate:

number-of-VLAN-ports-subject-to-L2-loop-detection/frame-transmission-rate-(pps) zueng000.tif sending-interval-(sec.)

For a channel group, VLAN number of ports is counted as one port per channel group.

Note #1: The transmission rate is automatically adjusted to within 200 pps in accordance with the above equation.
Note #2: When using either Spanning Tree Protocols, GSRP, or Ring Protocol, set the transmission rate to no more than 30 pps. If it is larger than 30pps, the normal operation of Spanning Tree Protocols and GSRP,Ring Protocol cannot be guaranteed.
Note #3: Frames that exceed 200 pps will not be sent. Loop failures cannot be detected on target ports or VLANs from which frames have not been sent. Make sure that you set the sending interval to achieve a transmission rate of no more than 200 pps.