S6 is the max out just now. Also youre Ixia only had 1 gig port?? How did you see packet drops. I ran the rfc throughput tests on the box and had these results.

Frame Size 64 128 256 512 1024 1280 1518

----------------------------------------------------------------------------

--------------------------------- Pair1 TxTput(fps) 1488095 844595 452899 234962 119732 96154 81274 %TxTput 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Pair2 TxTput(fps) 1488095 844595 452899 234962 119732 96154 81274 %TxTput 100.00 100.00 100.00 100.00 100.00 100.00 100.00

in other words I never dropped a packet. With QOS configured on the gig links I got....

Frame Size 64 128 256 512 1024 1280 1518

----------------------------------------------------------------------------

--------------------------------- Pair1 TxTput(fps) 844595 811688 452899 234962 119732 96154 81274 %TxTput 56.76 96.10 100.00 100.00 100.00 100.00 100.00 Pair2 TxTput(fps) 735294 811688 452899 234962 119732 96154 81274 %TxTput 49.41 96.10 100.00 100.00 100.00 100.00 100.00

From above with qos configured on the gig interfaces I halved the gig port at 64 byte packets and lost 4% at 128 bytes.

HTH - btw these figures are for my testing. In other words if you buy one based on the above figures then don't get the exact same throughput don't come moaning to me ;-D

Robert McCallum CCIE #8757 R&S