Users Manual – svs4021, svs2020,svs2050, svs2051, svs1020, svs1050, svs285, svs340, svs625
p. 17
Last Update 20.07.2009
3.2.3
Using jumbo frames
The transport efficiency in the streaming channel can be improved when using
“jumbo frames” in network transport. This will reduce the overhead which is
caused by maintaining header data with each data packet. A network packet
has usually a size of about 1500 bytes which can be increased to e.g. 16112 by
switching “jumbo frames” on. In addition to the network card “jumbo frames”
have to be supported also by a switch that forwards the image data stream
from a camera to the PC.
Adjusting higher packet sizes requires network cards that support jumbo
packets, e.g. Intel PRO/1000 PT which offers a single network port or Intel
PRO/1000 MT which offers two network ports. Other cards have to be checked
whether they contain an adjustment which allows for switching “jumbo frames”
on.
NOTE:
For Intel Pro/1000 cards the settings should be adjusted as follows:
Flow control:
Generate
Interrupt throttling rate: Minimal
Jumbo frames:
adjust to maximal value
All SVCam-GigE cameras support flow control and jumbo frames upto 16112
bytes.
3.2.4
Performance considerations
Each GigE camera is a
high-performance device
. In order to use the full
performance of a GigE camera a PC is required that meets at least the data
transfer figures that the connected camera is capable to deliver to the
application.
For example, a SVS625MFGE camera delivers a compound image data stream
consisting of two times 50 Megabytes/sec. of payload data plus network
overhead. Therefore the PC that operates that camera should be capable of
transferring that amount of data as a net data stream over all its internal
components like network card, PCI bus and others. A PC with a dual core
