Waters Network Systems
User’s Manual
Page 104
PS-2126M-POE
The IP TOS Priority affects the TOS fields of IP header. It has an 8-bit SERVICE TYPE field that
specifies how the datagram should be handled. The field can be divided into the following six
subfields: PRECEDENCE (3 bits), D-Type (Delay Priority, 1 bit ), T-Type (Throughput Priority, 1bit),
R-Type (Reliability Priority, 1bit ), M-Type (Monetary Cost Priority, 1bit ), and UNUSED.
PRECEDENCE 3-bits can be arranged in eight types of priorities corresponding to the 0~7 priority in
the following priority diagram. TOS Monetary Cost Priority Mapping works while M-TYPE in TOS
field of IP header of the packets received by the switch is configured.
Parameter description:
TOS Monetary Cost
Priority Mapping:
Each Priority can select Queue 0 ~ Queue 3. In Default, Priority 0 is mapped to Queue 0,
Priority 1 is mapped to Queue 0, Priority 2 is mapped to Queue 1, Priority 3 is mapped to
Queue 1, Priority 4 is mapped to Queue 2, Priority 5 is mapped to Queue 2, Priority 6 is
mapped to Queue 3, and Priority 0 is mapped to Queue 3.
Figure 5.70 – TOS Monetary Mapping
Function name:
DSCP Setting
Function description:
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.
DSCP can handle a total of 64 (0~63) kinds of Traffic Class based on the arrangement of 6-bit field
in DSCP of the IP packet. You can set these 64 types of Class that belong to queues 0~3.