KSwitch D10 MMT Managed Time Sensitive Ethernet Switch - Preliminary User Guide, Rev. 0.99
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5.2.
Credit Based Shaper
Credit Based Shaper is defined in the IEEE 802.1Q-2014 standard and is the ability to control the traffic access
bandwidth based on priorities. The highest priority queue can be assigned a higher access bandwidth relative to the
available bandwidth, which in turn gives packets a higher chance to be transmitted in a busy network.
The mechanism is realized through increasing/decreasing credit value of the specific queues, i.e., the credit for high
priority queues increases faster and therefore reaches the transmitting threshold more frequent than the low priority
queues. The algorithm includes two parts, namely assigning priorities to traffic classes/queues and assigning relative
access bandwidth (reflected in credits) to the queues.
5.2.1.
Configuration Examples
CLI commands example:
! Enable a 800 kbps credit based shaper on port 1, queue 6.
# configure terminal
(config)# interface GigabitEthernet 1/1
(config-if)# qos queue-shaper queue 6 800 kbps credit
! Disable the shaper on port 1, queue 6.
# configure terminal
(config)# interface GigabitEthernet 1/1
(config-if)# no qos queue-shaper queue 6
! Show configuration using 'show running-config'.
# show running-config
[...]
qos queue-shaper queue 6 800 kbps credit
5.2.2.
Status
CLI commands example:
!
Show status using 'show qos'.
# show qos
[...]
qos queue-shaper queue 0: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 1: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 2: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 3: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 4: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 5: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled
qos queue-shaper queue 6: enabled, rate 800 kbps, mode: line-rate, excess: disabled,
credit: enabled
qos queue-shaper queue 7: disabled, rate 500 kbps, mode: line-rate, excess:
disabled, credit: disabled