Net Optics PAD-CU-AR, PA-CU-AR manual 140% Utilization

10/100 Port Aggregator Tap

State 2: Side A + Side B becomes greater than 100% of the NIC's receive capacity.

Example: There is a burst of traffic, so Side A is now at 90 Mbps while Side B remains at 50 Mbps. The NIC's utilization is at 140%, requiring the use of memory to help prevent data loss.

Side	A	Active Response Dual
		Port Aggregator Tap

The extra 40 Mbps of traffic is 2 stored in the 1 megabyte buffer for Port A. Memory continues to fill until the 1 megabyte capacity is reached, or the burst ends.

(A separate 1 megabyte buffer is also available to handle a burst on Port B.)

A B 1 2

Router		Firewall
Memory	Side B
		1 Each using a single NIC, the monitoring
	Side A +	devices both receive all combined traffic
		from Side A and Side B, including physical
	Side B	layer errors.
	Monitoring
	Device 1
	Monitoring
	Device 2

Figure 5: 140% Utilization

State 3: Side A + Side B is once again less than 100% of the NIC's receive capacity.

Example: On a 100 Mbps link, Side A is again at 30 Mbps and Side B remains at 50 Mbps. The NIC's utilization is again at 80%.

Side	A	Active Response Dual
		Port Aggregator Tap

The Tap applies a first-in, first-out 1 process to all packets. Once the burst has ended and the NIC's utilization is again below 100 percent, the Tap first processes the packets that were stored in memory. As long as the NICʼs utilization remains below 100 percent, this process continues uninterrupted until the memory clears.

A B 1 2

Router						Firewall
Memory	Side B
					2	Once the memory has cleared, each
	Side A +					monitoring device begins receiving new
						data directly from the link. Each using
	Side B					a single NIC, both monitoring devices
						receive all traffic from Side A and Side B,
						including physical layer errors.
		Monitoring
		Device 1
			Monitoring
				Device 2

Figure 6: Return to 80% Utilization