Denial Of Service Dos - ABB REB670 Applications Manual

Section 18
Basic IED functions
18.3
18.3.1
462
• Control operations
• Set system time
• Enter and exit from test mode
• Change of active setting group
The binary input controlling the function is defined in ACT or SMT. The CHNGLCK
function is configured using ACT.
LOCK Binary input signal that will activate/deactivate the function, defined in ACT or SMT.
When CHNGLCK has a logical one on its input, then all attempts to modify the IED
configuration and setting will be denied and the message "Error: Changes blocked" will
be displayed on the local HMI; in PCM600 the message will be "Operation denied by
active ChangeLock". The CHNGLCK function should be configured so that it is
controlled by a signal from a binary input card. This guarantees that by setting that signal
to a logical zero, CHNGLCK is deactivated. If any logic is included in the signal path to
the CHNGLCK input, that logic must be designed so that it cannot permanently issue a
logical one to the CHNGLCK input. If such a situation would occur in spite of these
precautions, then please contact the local ABB representative for remedial action.

Denial of service DOS

Application
The denial of service functions (DOSFRNT, DOSLANAB and DOSLANCD) are
designed to limit the CPU load that can be produced by Ethernet network traffic on the
IED. The communication facilities must not be allowed to compromise the primary
functionality of the device. All inbound network traffic will be quota controlled so that too
heavy network loads can be controlled. Heavy network load might for instance be the
result of malfunctioning equipment connected to the network.
DOSFRNT, DOSLANAB and DOSLANCD measure the IED load from communication
and, if necessary, limit it for not jeopardizing the IEDs control and protection functionality
due to high CPU load. The function has the following outputs:
• LINKUP indicates the Ethernet link status
• WARNING indicates that communication (frame rate) is higher than normal
• ALARM indicates that the IED limits communication
1MRK 505 337-UUS -
Application manual