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Setting
● Ensure that there is sufficient network
bandwidth for the data volume to be sent out
by VN-C215VP4U.
●
Data volume to be sent by VN-C215VP4U varies
with the settings and number of distributions.
● The maximum bit rate from VN-C215VP4U is
about 9 Mbps.
Estimation of total bit rate
The JPEG file size per frame varies with the encoding
settings as well as input video signals. The following
table may be used as a reference. When VFS is
selected, the quantization table during JPEG
encoding will be maintained and the file size will
increase/decrease according to the input signals.
When AFS is selected, encoding will be performed
such that the average size of multiple JPEG images is
the target file size.
VN-C215VP4U accepts requests from up to a
maximum of 5 clients. In addition, it also allows
transmission of 1 multicast stream. The total frame
rate refers to the sum of these frame rates.
For example, when 10 fps is requested by 2
clients, and in addition multicast is transmitted at
a rate of 10 fps, the total frame rate will be:
10 + 10 + 10 = 30 fps
If the JPEG file size per frame is 30 KB, then the
total bit rate will be:
30 KB x 30 fps = 900 KB/s = Approx. 7.2 Mbps
Insufficient network bandwidth
When there is insufficient bandwidth, the number
of JPEG frames (frame rate) that the client can
acquire will decrease.
Network Delay
When the client acquires JPEG via TCP, VN-
C215VP4U will send out data while checking the
ACK from the client at the same time. For
networks with considerable delay, data cannot be
sent out until ACK is received, and therefore the
frame rate will drop.
Drop of frame rate due to network delay can be
eliminated by sending data via multicast.
Network Jitter
When there is considerable network jitter, delay time
may be prolonged and the image frame rate may drop.
Packet Loss
When acquiring images from VN-C215VP4U via
TCP, packet loss may be recovered by resending
by TCP. When there is considerable delay during
resending, however, missing data may occur and
the image frame rate may drop.
When packet loss occurs during multicast
sending from VN-C215VP4U, the image frame
rate may drop.
List of protocols and port numbers used
by VN-C215VP4U
VN-C215VP4U
uses the protocols and port
numbers listed below. Ensure that these ports are
allowed through the firewall when a firewall is to be
installed.
Network Requirements
Picture Quality
Control Method
VGA File
Size
QVGA File
Size
VFS
(Variable
File Size)
1 (High)
80 KB 27 KB
2
60 KB 20 KB
3
40 KB 13 KB
4
(Medium)
30 KB 10 KB
5
25 KB 8 KB
6
20 KB 7 KB
7 (Low)
15 KB 5 KB
AFS
(Average File Size)
Selection
may be
made from
the range
between 10
and 100 KB
Selection
may be
made from
the range
between 3
and 33 KB
Protocol/Port No. Purpose of Use
TCP/80 JPEG acquisition, Web
Settings page, API
TCP/20, 21 FTP
TCP/25 Mail delivery
TCP/User Setting No.
Alarm sending
UDP/User Setting No.
Alarm sending
UDP/User Setting No.
Multicast sending
UDP /123 SNTP
VN-C215VP_EN.book Page 32 Wednesday, December 20, 2006 4:26 PM