VigorSwitch P2260 User’s Guide
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D-Type (Delay Priority, 1 bit ), T-Type (Throughput Priority, 1bit), R-Type (Reliability
Priority, 1bit ), M-Type (Monetary Cost Priority, 1bit ), and 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 8-bit SERVICE TYPE field to accommodate a set of
differentiated services (DS). Under the differentiated services interpretation, the first six
bits comprise a codepoint, which is sometimes abbreviated DSCP, and the last two bits are
left unused.
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 be enabled at the same time. But, the
following precedence will decide whether these functions work or not.
1. enable both VIP and TOS
Choose priorities of VIP and TOS.
2. enable both VIP and DSCP
Choose priorities of VIP and DSCP.
3. enable both TOS and DSCP
Choose "DSCP".
4. enable both VIP and DSCP
Choose priorities of VIP and DSCP.
5. enable both 802.1p and TOS
Choose "TOS".
6. enable both 802.1p and DSCP
Choose "DSCP".
7. enable both 802.1p and DSCP and TOS
Choose "DSCP".
8. enable both 802.1p and DSCP and TOS and VIP
Choose priorities of VIP and DSCP.