RuggedCom RS400 用户手册

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页码 275
Classes of Service 
 
 
ROS™  v3.5 
186 
RS400 
Frame 
tagged ?
Received 
Frame
MAC Address in 
Static MAC Address 
Table?
Use Port Default 
CoS
To CoS 
Queues of 
Egress Ports
IP Frame ?
Y
Y
No
Y
No
No
Use TOS 
DSCP ?
Use Priority-to-
CoS Mapping
Use DSCP-to-
CoS Mapping
Use CoS 
Configured for 
the MAC address
No
Y
 
Figure 124: Determining The CoS Of A Received Frame  
 
After inspection, the frame is the forwarded to the egress port for transmission. 
7.1.2 Forwarding Phase 
The inspection phase results in the CoS of individual frames being determined.  When these 
frames are forwarded to the egress port they are collected into one of the priority queues 
according to the CoS assigned to each frame. 
CoS weighting selects the degree of preferential treatment that is attached to different priority 
queues.  The ratio of the number of higher CoS to lower CoS frames transmitted can be 
programmed.  If desired, the user can program that lower CoS frames are transmitted only after 
all higher CoS frames have been serviced.