Hardware and Software Requirements - Trading Technologies

Table 1:
Registry Setting TT Machine Description
DisableTaskOffload
IgnorePushBitOn
Receives
TcpAckFrequency
SynAttackProtect
TcpTmedWaitDelay
TCPWindowSize
Server Machines
Server Machines,
Client Machines
Server Machines
Remote Hosts,
WAN Routers
Remote Hosts,
WAN Routers
Remote Hosts,
WAN Routers
This toggles checksum offloading. In general, offloading
the checksum calculation to the device driver is
supposed to free up the OS from doing the work; therefore,
making the process more efficient. TT has tested
this, and it shows that leaving the OS to do the work is
actually faster and more efficient.
This allows any incoming packets without Push Bit set
to be treated as though they were sent that way. This
makes the application more efficient by handling fragments;
for example, say a 1500 byte packet turns up.
Normally TCP would hold this until it receives what it
assumes to be the end of the stream, or a packet with
Push Bit set. This adds latency and can stall the application
from handling the data because it is now waiting
on the OS to pass it up. With this setting, TT's application
can dissect the 1500 byte packet sent out - say 10
prices - but retain a small fragment while waiting for
the next packet to arrive. This means that data is send
all the time, making it a more consistent flow.
To make better use of the bandwidth the Nagle Algorithm
is used. This means that it accumulates data until
it receives an ACK from the receiving side; however, if
delayed ACKs are turned on, it can create an even
greater latency in sending and receiving data.
This closes half open TCP connections faster so a SYN
attack cannot create a resource failure.
This decreases the time wait state for a closed TCP session.
Normally the system takes three (3) minutes to
recover the resource, but this can be set to 30 seconds.
This allows us to set the size of the TCP receive window
to suit the bandwidth of the line. This is now normally
set in the TTM config file.