Contemporary Control Systems Compact Managed Switches Software Manual for Console Access - Manual (Page 30)

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4.3.7.3 Configure TOS/DiffServ Priority
The IP header contains an eight-bit field originally known as the Type of Service (TOS)
field — but TOS priority had little acceptance. Subsequently, these eight bits were
redefined to become the more popular Differentiated Services (DiffServ) field.
When configuring the TOS/DiffServ priority (Figure 23), you must choose TOS or
DiffServ. This sample screen is for an 24-port switch.
Figure 23 — Configure TOS/DiffServ Priority
You register your choice of QoS in the topmost field which is labelled QoS Type (the
default setting is TOS). Below the TOS/DiffServ selection field are the fields for
enabling or disabling the individual ports. Fewer ports would be displayed for an 8- or
16-port switch. Regardless of the type of QoS chosen, each port (Disabled by default)
must be individually Enabled to establish its QoS service.
If TOS priority is selected, one additional screen is used for mapping the priority details,
but two more screens are needed if the selected QoS Type is DiffServ. Access to these
screens is via the Map TOS(DSCP) Priority option in the lower right portion of the
screen. Each screen is discussed and illustrated below.