Transcript TCP Offload Engines

TCP/IP Offload Engines
by Davud Turkdil and Cory Ford
Note that the relative CPU cost per
megabit of throughput was higher
for the faster CPU, in some cases
more than double that observed at
800 MHz because memory and I/O
speeds have increased at a much
slower rate than CPU speeds.
System price/performance
values for ASIC and discrete,
board-level TOE solutions (AS
OF 2002)
A TOE is a specialized network
device that implements a
significant portion of the TCP/IP
protocol in hardware, thereby
offloading TCP/IP processing
from software running on a
general-purpose CPU.
Benefits
•Reduces the bandwidth cost by 33%
•Significantly increased CPU cycles for
application processing
•Significant drops in latency, reducing
client response times
All of the TCP/IP and checksums
sections and much of the
Interrupts, buffering and data
movement can be taken over by
TOE’s. Effectively relieving
around half of the CPU overhead.
TCP/IP processing can consume
most of a CPU's processing
power with standard Ethernet
network interface cards. At small
packet sizes, the CPU utilization
can exceed 80%, significantly
reducing the amount of CPU
cycles available.
Conclusion
Direct Data Placement (DDP)
•Inputting data directly into the
application buffer
•Greatly reduces TOE buffer size
•Can currently achieve 3Gbps
throughput
After a little research on the subject we
have concluded that TOEs are very useful
in saving CPU power and increasing
throughput of the network. We believe
once 10-GbE networks are more common
then TOEs will be necessary.