Ericsson AVP 1000 1RU, Справочное руководство, Страница: 328 / 508

Advanced Video Processing and Networking
6-8
EN/LZT 790 0023/1 R16A
Table 6.1 IP Overhead
Item Overhead factor Comments
MPEG-2 TS 1.0
UDP 1324/1316 = 1.006 UDP header=8 bytes
IP 1344/1324 = 1.015 IP header=20 bytes
Ethernet 1358/1344 = 1.010 Eth header=14 bytes
Total overhead factor becomes: 1.006 x 1.015 x 1.010 = 1.031 or 3.1% overhead.
Note: The number of MPEG-2 TS packets one can map down into each UDP
frame is variable (between 1 and 7). Usually 7 is used for minimum
overhead. This is also used in the above calculation.
6.2 Data Network Redundancy
6.2.1 Redundancy
Note: Both outputs of a pair are active at the same time; therefore the use of
primary and secondary ports is meaningless in this configuration.
The four Ethernet data ports operate as two redundant pairs. Data 1 and 2 (Ge1
with Ge2) are inputs and Data 3 and 4 (Ge3 with Ge4) are outputs.
When an output transport stream is defined, it is assigned by the user to Data 3 and
4.
Both ports are independent of each other i.e. the IP address, MAC address, subnet
mask and default gateway can have different settings. Both ports are active at the
same time and transmit the same data. If both ports are configured to be on the
same subnet, only one port will respond to ICMP messages.
Figure 6.4 Data Network Redundancy
The data ports can raise an alarm during abnormal operational conditions.