Altera 100G Interlaken MegaCore Function - Manual (Page 105)

Table A-1: Packet Processing Time in Dual Segment Mode at 225 MHz
The time to process two consecutive packets at 225 MHz is simply the time taken by the relevant number of cycles
at 225 MHz. The required maximum time per packet is derived in the discussion of the requirements for single
segment mode.
Packet Size (Bytes)
Processing Time
Required Maximum Time per
Packet (ns) (derived earlier)
Number of
Cycles for Two
Consecutive
Packets
At 225 MHz:
Time for Two
Consecutive
Packets (ns)
Average Time
per Packet (ns)
65 3 13.33 6.66 6.8
129 5 22.23 11.12 11.9
Both of the average times per packet are sufficiently short, based on the packets per second requirements
for the different sized packets (6.66 < 6.8 and 11.12 < 11.9). The same calculations applied to lower
frequencies yield an average time per packet that is not sufficiently short. Therefore, 225 MHz is the
recommended frequency for the two user data transfer interface clocks in your 12-lane, dual segment
mode 100G Interlaken IP core.
UG-01128
2015.05.04
Performance and Fmax Requirements for 100G Ethernet Traffic A-3
Performance and Fmax Requirements for 100G Ethernet Traffic Altera Corporation
Send Feedback