The inbound and outbound rate limiting can be configured separately or together. During traffic statistics, inbound and outbound traffic is calculated separately. The rate limiting is affected by the inter-frame gap and preamble, so the actual rate limit may be different from the expected one.
Inter-frame gap and preamble: By default, the switch calculates the inter-frame gap and preamble of packets when the device calculates the traffic policing rate, traffic shaping rate, or rate limit. That is, the rate of collected traffic refers to the rate of packets, inter-frame gap, and preamble. In V200R005 and later versions, you can run the qos-car exclude-interframe and qos-shaping exclude-interframe commands to configure the device to not calculate the inter-frame gap and preamble of packets when the device calculates the traffic policing rate, traffic shaping rate, or rate limit, improving the rate limit accuracy.