UNUSED (1bit).
User can randomly control these fields to achieve some special QoS goals. When bits D, T, R, or M set, the D bit requests low delay, the T bit requests high throughput, the R bit requests high reliability, and the M bit requests low cost.
DiffServ DSCP Priority act on DSCP field of IP Header. In the late 1990s, the IETF redefined the meaning of the
High Priority Packet streams will experience less delay into the switch. For handing different priority packets, each egress port has designed up to 4 queues. Each QoS is influenced by two scheduling, WRR (Weighted Round Robin) and Strict Priority as well. When you finish setting the priority mapping to the queue, WRR scheduling will distribute the bandwidth according to the weight you set for 4 queues (queue 0 to queue 3). Another scheduling is Strict Priority dedicated for the function named VIP Port of QoS. While we select some ports as the VIP Port, these ports will own the highest transmitting priority in egress queue of the switch.
The QoS functions as we mentioned above are able to enable at the same time. But, the following precedence will decide whether these functions work or not.
zEnable both VIP and TOS
zEnable both VIP and DSCP
zEnable both TOS and DSCP
zEnable both VIP and DSCP
zEnable both 802.1p and TOS
zEnable both 802.1p and DSCP
zEnable both 802.1p and DSCP and TOS
zEnable both 802.1p and DSCP and TOS and VIP
**VIP/DSCP > TOS > 802.1p (Final result)
3.19.1Global
When you want to use QoS function, please enable QoS Mode in advance. Then you can use MAC Priority, 802.1p Priority, IP TOS Priority, DiffServ DSCP Priority, or VIP Port functions and take effect. In this function, you can Enable QoS Mode. Choose any of Priority Control, such as 802.1p, TOS, DSCP. Moreover, you can select Scheduling Method of WRR (Weighted Round Robin) or Strict Priority. Next, you can arrange Weight values for queue 0 to queue 3.
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