User`s guide

NetAtlas Enterprise Ethernet Switch Manager User’s Guide
127 Chapter 14 Switch Configuration
DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (ToS)
field in the IP header. The DS field contains a 2-bit unused field and a 6-bit DSCP field which
can define up to 64 service levels. The following figure illustrates the DS field.
DSCP is backward compatible with the three precedence bits in the ToS octet so that non-
DiffServ compliant, ToS-enabled network device will not conflict with the DSCP mapping.
Figure 89 DiffServ: Differentiated Service Field
The DSCP value determines the forwarding behavior, the PHB (Per-Hop Behavior), that each
packet gets across the DiffServ network. Based on the marking rule different kinds of traffic
can be marked for different priorities of forwarding. Resources can then be allocated
according to the DSCP values and the configured policies.
You can configure the DSCP to IEEE 802.1p mapping to allow the switch to prioritize all
traffic based on the incoming DSCP value according to the DiffServ to IEEE 802.1p mapping
table.
Click Configuration, Switch Configuration and the DSCP tab to display the screen as
shown.
Figure 90 Switch Configuration: DSCP
The following table describes the labels in this screen.
Table 59 Switch Configuration: DSCP
LABEL DESCRIPTION
0 … 63 This is the DSCP classification identification number.
To set the IEEE 802.1p priority mapping, select the priority level from the drop-down list box.
Apply Click Apply to save the changes.
Cancel Click Cancel to discard all changes and start configuring the screen again.
DSCP (6 bits)
DS (2 bits)