VEGA FL SWITCH SFN… User Manual
Page 13
FL SWITCH SFN…
2732_en_D
13
PHOENIX CONTACT GmbH & Co. KG • 32823 Blomberg • Germany • Phone: +49-(0) 5235-3-00
PHOENIX CONTACT • P.O.Box 4100 • Harrisburg • PA 17111-0100 • USA • Phone: +717-944-1300
www.phoenixcontact.com
As an example, if a total of four switches are connected
together, there will be a first switch then three additional
switched segments. This means that three times the
overhead value must be used.
4.
Add all the application traffic (step 2.) with all the over
head values (step 3.) and compare with the total
available bandwidth.
Example 1
Assuming gigabit devices are used with 9000-byte jumbo
frames and a total of three cascaded switches. Each switch
has one 8 bit/pixel camera plus 10 Mbps of miscellaneous
traffic from other ports.
Figure 14 depicts an example with three cameras
connected to individual switches. Each camera is
configured for an 8 bits per pixel color depth, creating a
load of 182 Mbps per camera (see Table 2) with a total
traffic load of 546 Mbps. Frame size is configured to 9000
bytes creating an overhead of 180 Mbps (see Figure 13) for
each cascading switch for a total of 360 Mbps.
Figure 14
9000-byte frame size example
Adding the camera data and overhead together indicates a
total traffic load of 906 Mbps, leaving 94 Mbps of the
1000 Mbps total unused.
Example 2
To take advantage of the bandwidth not used in example 1,
assume one of the cameras is now required to operate at
12 bits per pixel.
The increased camera color depth increases the traffic load
to a total of 639 Mbps. Combined with the 360 Mbps
overhead with a 9000-byte frame size, the total bandwidth is
999 Mbps. While technically within the capability of a
1000 Mb switch, any additional traffic across the
transmission line could result in frame loss.
Figure 15
8000-byte frame size example
One possible solution is to change the frame size to
8000 bytes, reducing the overhead (see Figure 15). The
reduced frame size results in a total overhead of 320 Mbps.
Combined with the camera traffic load, the resulting
bandwidth requirement is 959 Mbps, allowing some space
for additional traffic.
input
+
_
a u to
HP LP 2065
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LN
K/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LN
K/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
1
2
3
4
T 1 1 0
P
o
w
e
r E
d
g
e
P
o
w
e
r E
d
g
e
182 Mbps
182 Mbps
182 Mbps
180 Mbps
180 Mbps
input
+
_
a u to
HP LP 2065
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LN
K/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
X1
X
3
X5
X7
FL
S
WITCH
S
FN
8
TX
Ord.-No.: 2
8
91929
100
LNK/
AC
T
100
LN
K/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
US
X2
X4
X6
X
8
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
100
LNK/
AC
T
1
2
3
4
T 1 1 0
P
o
w
e
r E
d
g
e
P
o
w
e
r E
d
g
e
182 Mbps
182 Mbps
275 Mbps
160 Mbps
160 Mbps