This read-write integer (0..52000000) defines the Excess Information Rate for a connection whose CIR is configured as 0: a value of 0 causes the EIR to default to the port speed, while a nonzero value sets the EIR explicitly and is used for ingress policing, always capped at the port speed; it applies only to zero-CIR connections. An administrator sets zeroCirConEir on best-effort connections that have no committed rate but still need a bounded ingress policing ceiling below full port speed. For example, on a zero-CIR connection over a port speed of 10,000,000 bps, setting zeroCirConEir to 5,000,000 would police ingress traffic to half the port speed instead of letting it default to the full port rate.