An Investigation into Transport Protocols and Data Transport ...

A.2. Network Interface Cards 279
PCI Bus PCI Word Data Rate Inverse Data
Speed (Mhz) Length (bits) (Gbit/sec) Rate (µsec/byte)
33 32 1.056 0.00758
66 32 4.224 0.00379
33 64 2.112 0.00379
66 64 4.356 0.00189
133 64 8.512 0.00094
Table A.8: Theoretical data rates of PCI bus speeds.
NIC Speed Inverse Data Rate
(Mbit/sec) (µsec/byte)
10 0.80000
100 0.08000
1,000 0.00800
10,000 0.00080
Table A.9: Theoretical data rates of various NIC speeds.
Model Processor Front Side Data Rate Inverse Data Rate
Bus (Mhz) (Gbit/sec) (µsec/byte)
Supermicro P4DP8-G2 32-bit 400 12.8 0.000625
HP RX2600 64-bit 800 51.2 0.000156
Table A.10: Theoretical memory data rates of PCs.
which data can be transferred, τ. to be:
1
τ = 2
t m
+ 2 t p
+ 1 t n
(A.1)
Where t m is the rate at which data is copy to or from memory, t p is the
rate at which data is transferred over the PCI bus and t n is the rate at which
data is transferred over the network (assuming no losses nor congestion).
By varying the size of the ‘request’ packet, and keeping the ‘response’
packet size constant, the rate at which packets are processed by the various
subsystems can be calculated. Also the actual propagation delay through the