Baumer VCXG - VCXG Interface Functionalities; VCXG Device Information; Packet Size and MTU; Inter Packet Gap (IPG)

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10. VCXG - Interface Functionalities
10.1 Device Information
This Gigabit Ethernet-specic information on the device is part of the Discovery-Acknowl-
edge of the camera.
Included information:
▪ MAC address
▪ Current IP conguration (persistent IP / DHCP / LLA)
▪ Current IP parameters (IP address, subnet mask, gateway)
▪ Manufacturer's name
▪ Manufacturer-specic information
▪ Device version
▪ Serial number
▪ User-dened name (user programmable string)
10.2 Packet Size and Maximum Transmission Unit (MTU)
Network packets can be of different sizes. The size depends on the network components
employed. When using GigE Vision
®
compliant devices, it is generally recommended to
use larger packets. On the one hand the overhead per packet is smaller, on the other
hand larger packets cause less CPU load.
The packet size of UDP packets can differ from 576 Bytes up to the MTU.
The MTU describes the maximal packet size which can be handled by all network com-
ponents involved.
In principle modern network hardware supports a packet size of 1500 Byte, which is
specied in the GigE network standard. "Jumboframes" merely characterizes a packet
size exceeding 1500 Bytes.
Baumer VCXG cameras can handle a MTU of up to 16384 Bytes.
10.3 Inter Packet Gap (IPG)
To achieve optimal results in image transfer, several Ethernet-specic factors need to be
considered when using Baumer VCX cameras.
Upon starting the image transfer of a camera, the data packets are transferred at maxi-
mum transfer speed (1 Gbit/sec). In accordance with the network standard, Baumer em-
ploys a minimal separation of 12 Bytes between two packets. This separation is called
"inter packet gap" (IPG). In addition to the minimal IPG, the GigE Vision
®
standard stipu-
lates that the IPG be scalable (user-dened).
Notice
According to the Ethernet standard, IPG
min
can not be lower than 12 Bytes.
IPG:
The IPG is measured in
ticks.
An easy rule of thumb is:
1 Tick is equivalent to 1 Bit
of data.
You should also not forget
to add the various ethernet
headers to your calculation.