LevelOne GEL-1061, Руководство пользователя

Страница: 199 / 500

Chapter 9
| Class of Service
Layer 3/4 Priority Settings
– 199 –
Figure 118: Setting the Trust Mode
Mapping
Ingress DSCP Values
to Internal DSCP
Values
Use the Traffic > Priority > DSCP to DSCP page to map DSCP values in incoming
packets to per-hop behavior and drop precedence values for internal priority
processing.
The DSCP is six bits wide, allowing coding for up to 64 different forwarding
behaviors. The DSCP replaces the ToS bits, but it retains backward compatibility
with the three precedence bits so that non-DSCP compliant, ToS-enabled devices,
will not conflict with the DSCP mapping. Based on network policies, different kinds
of traffic can be marked for different kinds of forwarding.
Command Usage
◆
Enter per-hop behavior and drop precedence for any of the DSCP values 0 - 63.
◆
This map is only used when the priority mapping mode is set to DSCP (see
page 198 ), and the ingress packet type is IPv4. Any attempt to configure the
DSCP mutation map will not be accepted by the switch, unless the trust mode
has been set to DSCP.
◆
Two QoS domains can have different DSCP definitions, so the DSCP-to-PHB/
Drop Precedence mutation map can be used to modify one set of DSCP values
to match the definition of another domain. The mutation map should be
applied at the receiving port (ingress mutation) at the boundary of a QoS
administrative domain.
Parameters
These parameters are displayed:
◆
Port – Specifies a port.
◆
DSCP – DSCP value in ingress packets. (Range: 0-63)
◆
PHB – Per-hop behavior, or the priority used for this router hop. (Range: 0-7)