Qos (Quality Of Service) Configuration - Waters Network Systems ProSwitch 2800M Operating Manual

5.22

QoS (Quality of Service) Configuration

The switch supports the following five QoS functions:

MAC Priority

802.1p Priority

IP TOS Priority

DiffServ DSCP Priority

Port Based Priority (VIP Port)
Packets in the VIP Port will have highest transmitting priority.
destination address of MAC in packets. VLAN tagged priority field is affected by the 802.1p
Priority setting.
IP TOS Priority affects TOS fields of IP header. It has 8-bit SERVICE TYPE field that specifies
how the datagram should be handled. The field could be divided into six subfields as follows,
PRECEDENCE (3 bits), D-Type (Delay Priority, 1 bit), T-Type (Throughput Priority, 1 bit), R-Type
(Reliability Priority, 1 bit), M-Type (Monetary Cost Priority, 1 bit), and UNUSED (1 bit).
You 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. 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 four queues. Each QoS is influenced by
two scheduling, WRR (Weighted Round Robin) and Strict Priority as well. Once the priority
mapping has been set, WRR scheduling will distribute the bandwidth according to the weight
you set for four queues (queue 0 to queue 3). Another scheduling type is Strict Priority which is
dedicated for the function named VIP Port of QoS. Ports selected as the VIP Ports own the
highest transmitting priority in egress queue of the switch.
Waters Network Systems 2800M/MR User's Manual
MAC Priority act on the
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