Overview | Section |
The two methods of using the socket services are as follows:
•Dedicated Control Bits (Socket Service Request Switches)
Requests can be made to a socket service by setting parameters and then merely manipulating specific Socket Service Request Switches.
•CMND(490)
Requests can be made to a socket service by sending service request commands to the Ethernet Unit.
Note One of the main differences between using Socket Service Request Switches and using CMND(490) is in the number of sockets that can be connected simultaneously, as shown in the following table.
Protocol | Socket Service Request | CMND(490) |
| Switches |
|
|
|
|
UDP | Total of 8 sockets max. | 8 sockets max. |
|
|
|
TCP |
| 8 sockets max. |
|
|
|
6-3-2 Using Socket Services with Socket Service Request Switches
Socket services can be used by setting the parameters in a Socket Service
Parameter Area in the CPU Bus Unit Area and then turning ON a Socket
Service Request Switch.
When using Socket Service Request Switches, a maximum of 8 sockets can be opened simultaneously for the UDP and TCP combined. Also, the same socket number cannot be used simultaneously for both UDP and TCP. (There is only one Socket Service Parameter Area for each socket, i.e., the same
area must be used for both UDP and TCP.)
An illustration of using Socket Service Request Switches to execute socket services is provided below.
CPU Unit | Ethernet Unit |
Socket Service | Sockets |
Request Switches | Refreshed |
| |
Socket Service | (See Note 1.) |
| |
Parameters | Refreshed |
| |
| (See Note 2.) |
TCP data transfers
UDP data transfers
Host computer or other device
Sockets | System User program | |
call | ||
|
Note 1. Socket Service Request Switches in the CPU Bus Unit Area in the CIO Area are used to send a service request from the CPU Unit to the Ethernet Unit.
2.The Socket Service Parameters in the CPU Bus Unit Area in the DM Area are used to specify the service being requested from the Ethernet Unit. The CPU Bus Unit Area in the DM Area is also used to receive results of processing from the Ethernet Unit to the CPU Unit.
After setting the required parameters in a Socket Service Parameter Area in the CPU Bus Unit Area in the DM Area, the Socket Service Request Switches can be used to request opening, sending, receiving, or closing for either the UDP or TCP protocol. When requesting a send, send data at the send/receive data addresses set in the parameter area is sent. When requesting a
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