discuss:
Flow Control Options Division Inbound and Outbound, Outbound take advantage of existing program
Interface and server capabilities.
discuss:
Outbound value should set the stream control settings to go out.
If you can set it separately to set it after setting.
discuss:
If the server cannot zone into the flow control, it should ignore the stream control command,
And the flow control option should be set based on the flow control command.
IAC SB COM-port-option set-lineestate-mask
Customer-> Server, set 1-bit mask to send a Notify-LineState option (see Part 4
)
)
When the server's LINESTATE changes, the server will put new LINESTATE and LINESTATE-
Mask is "and" process, if the result is not zero, the server will send and the result. If it is greater than one satisfaction
LINESTATE-MASK, only 1 Notify-Linestate, with all the satisfied bits, will be sent to the client.
Set-lineestate-mask can be combined:
These values are the same as in the Notify-LineState option.
The set-letteate-Mask value is based on the current most popular UART (COM port control chip).
Bit position value meaning
7 128 timeout error
6 64 Transfer Shift Register Empty
6 64 Transfer Shift Register for empty or transmitting switch registers
5 32 Transfer Holding Register EMPTY
5 32 Transfer Hold Register is empty
4 16 interrupt detection error
3 8 frame errors
3 8 frame errors
2 4 parity error
1 2 overloaded error
0 1 data ready
discuss:
When set-linestate-mask value is 0 Prevent the server from sending the Notify-LineState option to the customer.
discuss:
When the set-letteate-mask value is 255, the server is allowed to change when the server's LINESTATE changes,
Send a Notify-LineState option to the customer.
discuss:
The server's LINESTATE-MASK initial value is 0.
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After receiving a NOTIFY-LINESTATE, the customer does not have to send a new SET-LINESTATE-MASK.
LINESTATE-MASK is reset when the server is reset when the dialog is set or rebuilt.
LINESTATE-MASK is reset when the server is reset when the dialog is set or rebuilt.
IAC SB COM-port-option set-modemstate-mask
Customer-> Server, set 1-bit mask to send a Notify-modemState option
When modemState changes on the server, the server will have the original ModemState-Mask and new
ModemState is performing and calculated. If the result is not zero, the server will send and the result is
The Notify-ModemState option.
If more than one bit meets modemState-Mask, there is only 1 Notify-ModemState, with all the satisfaction
The bit will be sent to the customer.
The set- modemstate-mask may be any Combination of Bits as listed
Below.
Set-modemState-Mask can be the same as any combination of the following: the value and the Notify-ModemState option.
Set-modemstate-Mask value is based on the current most popular UART (COM port control chip)
Bit position value meaning
7 128 Receive linear signal detection (carrier detection)
6 64 visit indication (knocking on the door)
5 32 data-set-ready signal status
4 16 Clear-to-send signal status
3 8 DELTA Receive linear signal detection
2 4 trailing-edge ring detector
1 2 Delta Data-Set-Ready
0 1 Delta Clear-to-Send
discuss:
0 Set-ModemState-Mask values will prevent the server from sending the Notify-ModemState option to the customer.
discuss:
When the set-modemstate-mask value is 255, the server is allowed to change when the machine's modemState changes
, Send the Notify-ModemState option to the customer.
discuss:
discuss:
The server's ModemState-Mask initial value is 255.
discuss:
After receiving a NOTIFY-MODEMSTATE, the customer does not have to send a new set-modemState-Mask
ModemState-Mask resets when the value of the server is kept until the client is set or rebuilt.
IAC SB COM-Port-Option Purge-Data
Customer-> Server, require the server to immediately clear all data involved in buffering. 1 byte.
Value clear data buffer
0 can be used for future use
1 Clear server receive data buffer
2 Clear server transfer data buffer
3 '1' '2'
4-127 can be used for future use
4.
Notice of linear changes in COM port and modem linearity
Server transmission is not limited by time and number of times
Once the COM port or modem linear changes, the server should immediately send the appropriate command to the customer.
Customers don't have to respond to the command.
Iac SB COM-port-Option Notify-Linestate
Value is 1 byte
Multi-bit Value can be transferred once
Bit position value meaning
7 128 timeout error
6 64 Transfer Shift Register Empty
5 32 Transfer Holding Register EMPTY
4 16 Break-Detect Error
4 16 Break-Detect Error
3 8 frame error
2 4 Parity Error
1 2 Overrun Error
0 1 Data READY
discuss:
LINESTATE is the linear state of the UART on the access server. IAC SB COM-Port-Option Notify-ModemState
Value is 1 byte
Multi-bit Value can be transferred once
Bit position value meaning
7 128 Receive Line Signal Detect
6 64 Ring Indicator
6 64 Ring Indicator
5 32 Data-Set-Ready Signal State
4 16 Clear-to-Send Signal State
3 8 Delta Receive Line Signal Detect
2 4 Trailing-Edge Ring Detector
1 2 Delta Data-Set-Ready
0 1 Delta Clear-to-Send
5.
Flow control
Customer <-> server, unreasonable, number of times limited
IAC SB COM-Port-Option FlowControl-Suspend IAC SE
IAC SB COM-Port-Option FlowControl-Suspend IAC SE
The sender of this command requests the receiver to postpone the transfer of data and command until the send end is sent.
FlowControl-resume command
Iac SB COM-Port-Option FlowControl-Resume Iac SE
The sender of this command requests the receiver to resume sending data and commands.
discuss:
Remote login is initialized to Resume State between customers and servers.
There is no need to send the resume command during initialization.
discuss:
You can send multiple parallel pause commands at the same time
The second pause command can be ignored
Transfer recovery when you encounter the first single resume command.
discuss:
The flow control option is designed to handle the flow control of the Telnet dialogue of the client to the server.
This option is in RFC 1372:
Remote login stream control options
Remote login stream control options
RFC 1372 implements streaming using a single character XON / XOFF technology.
This leads to 2 problems.
First, the stream control character may be a valid data.
Stream control character may be used to end the stream control between the terminals at the end of use (customer application to remote server
Dialing).
6 security considerations
2 security issues need to be discussed;
Verify, reset resources.
Verification can follow the Kerberos confirmation protocol (RFC 1411) [3] or SPX confirmation protocol (RFC 1412)
[4].
When the dialog is terminated, the server must ensure that the connection is disconnected, and the COM port setting is restored to the defined value.
This ensures that the COM port is in a known state, ready to build the next customer dialogue.
This will make the operation more predictable while avoiding a new construction from the random COM port configuration.
The problem of dial-up dialog happening.
-
The time limit, I hope is ━━━ 10,000 years
━━━━━━━━━━━━━━━━━? ?━???????
