KSwitch D10 MMT Managed Time Sensitive Ethernet Switch - Preliminary User Guide, Rev. 0.99
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5.3.3.
Status
CLI commands example:
! Show status using 'show tsn tas status'.
# show tsn tas status interface 10GigabitEthernet 1/1
interface
GateEnabled :
TRUE
OperGateStates :
0x1f
OperCycleTime :
110 ms
OperCycleTimeExtension:
9000 nanoseconds
OperBaseTime :
4300 seconds, 500 nanoseconds
ConfigChangeTime :
4300 seconds, 500 nanoseconds
TickGranularity :
0 tenths of nanoseconds
CurrentTime :
4311 seconds, 827669856 nanoseconds
ConfigPending :
FALSE
ConfigChangeError :
0
SupportedListMax :
256
OperControlListLength :
3
GateControlEntry 0 : GateStates 0x80, TimeInterval 20000000 nanoseconds, GateOperation
set-hold
GateControlEntry 1 : GateStates 0x60, TimeInterval 30000000 nanoseconds, GateOperation
set-release
GateControlEntry 2 : GateStates 0x1f, TimeInterval 50000000 nanoseconds, GateOperation
set
! Disable Time Aware Shaper on port 1.
# configure terminal
(config)# interface 10GigabitEthernet 1/1
(config-if)# no tsn tas gate-enabled
5.3.4.
Configuration Considerations
The max-sdu parameter is only used to calculate the guard band time: gbt = maxsdu* 8 / LINK_SPEED. Note, that on
Fireant, frames larger than max-sdu are not rejected. The max-sdu is defined for each interface, queue and as a
result, gbt’s can be configured for each traffic class on an interface.
The required guard band time can be reduced if preemption is used. If the traffic class being closed consist of
preemptible frames, and the class being opened consists of express frames, then a set-hold operation can be
included as part of the gate operation. This causes any currently transmitting preemptible frame to be preempted,
reducing the latency before the port is ready to transmit express frames.
When a gate operation closes an input in a scheduler element, that input is permanently blocked until another gate
operation opens it again. Similarly, a set-hold on a port remains in effect until another gate operation does a set-
release.
This needs to be kept in mind when stopping a TAS list. If the last gate operation in the TAS list leaves any scheduler
element input closed, or leaves a set-hold in effect, they can be left indefinitely, possibly causing frames to be
blocked in the switch.
If one of the gate operations in a TAS list opens everything, then the TAS list can be arranged so that this is the last
operation in the TAS list. A TAS list always completes its cycle before stopping, thus this leaves everything open after
the TAS list is stopped.
Alternatively, after stopping a TAS list that leaves inputs closed or set-hold in effect, it is necessary to configure a
dummy TAS list with an "open all" gate operation and run it for one cycle.