A system with on-demand port block allocations is dynamic with a possibility of generating a high volume of logs. Transporting NAT logs through ESM accounting relies on a generic RADIUS accounting infrastructure implemented in the SR which supports multiple RADIUS servers and failover mechanisms. In cases where the rate of accounting message exceeds the capacity of the entire accounting system, the queue of the accounting message toward the RADIUS servers in SR start to fill up. This can be caused by the internal condition in the SR by slow or even unresponsive RADIUS servers. Considering that NAT is only a contributor of the accounting messages in a larger accounting framework that includes ESM, the rate of the allocation and de-allocations of extended port blocks is internally limited. Although this does not prevent loss of accounting messages in the overloaded accounting system (for example, caused by slow RADIUS servers), it helps to reduce the chances that the system become overloaded.