Paradise Datacom RA 5785, Руководство по эксплуатации

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Operations Manual, HPA3, Mini Compact Outdoor SSPA 208143 REV - 71
low overhead resulting in minimal impact to network performance. The control application
sends a UDP request to SSPA unit and waits for response. The length of time the control
application waits depends on how it is configured. If the timeout is reached and the control
application has not heard back from the agent, it assumes the packet was lost and
retransmits the request. The number of the retransmissions is user configurable.
The Paradise Datacom SSPA Ethernet IP interface can use UDP ports from 0 to 65553 for
sending and receiving. The receiving port needs to be specified through the front panel menu.
For sending, it will use the port from which the UDP request originated. Of course, it is up to
the user to select an appropriate pair of ports that are not conflicting with standard IP ser-
vices. Paradise Datacom recommends usage of ports 1038 and 1039. These ports are not
assigned to any known application.
As an application layer protocol (which actually carries meaningful data), the standard SSPA
serial protocol was selected. This protocol proves to be extremely flexible and efficient. It is
also media independent and can be easily wrapped into another protocol data frame. An ex-
ample of the UDP frame with encapsulated Paradise Datacom protocol frame is shown on
Figure 8-6 .
A detailed OSI model for the RM SSPA M&C interface is represented in Table 8-10 .
This set of Ethernet IP protocols is currently supported by Paradise Datacom Universal M&C
package (Compact Outdoor SSPA). The software is supplied on CD with the unit, or can be
downloaded by registered users from the company web site, http://www.paradisedata.com.
UDP Header
(8 bytes)
SSPA Serial Protocol Frame
(11+N Bytes, 0<N<128)
Figure 8-6: UDP Redirect Frame Example
CRC 16
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OSI Layer Protocol Notes
Application
Paradise Datacom CO
SSPA Serial Protocol
Frame structure described in Section 8.0
Transport UDP
Connectionless transport service. MTU on target PC
must be set to accommodate largest SSPA Serial Pro-
tocol Frame. Set MTU to a value larger than 127 bytes.
Network IP
ARP, RARP and ICMP Ping protocols supported by
RM SSPA controllers. Static IP Address only, no DHCP
support.
Data Link Ethernet 10/100 Base-T Network
Physical
Standard CAT5 (CAT
6) Network Cable
Maximum node length 100 m
Table 8-10: OSI Model for Compact Outdoor SSPA Ethernet IP Interface