What is the typical value of burst size to be used for rate-limiting on Layer 3 (L3) switches?
A. L3 switches implement an approximation of the single token bucket algorithm in firmware, and a reasonable burst size for the range of traffic rates is about 20,000 bytes. The burst size should be chosen to include at least one maximum-size packet. With each arriving packet, the policing algorithm determines the time between this packet and the last packet, and calculates the number of tokens generated during the elapsed time. It then adds this number of tokens to the bucket and determines whether the arriving packet conforms to or exceeds the specified parameters.
