User guide

EDA System Services
1/1551-HSC 901 35/3 Uen C 2005-12-02
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Mapping and
Queuing
Scheduling
Entrance
Link
Exit
Link
High Priority Queue
Low Priority Queue
“Voice”
Class
“Data”
Class
Network
Service Class
Policy
Figure 39 Differentiated Services in an Ethernet Switch
When a frame is received, the mapping and queuing process determines
by examining the header, the destination port and the queue in which the
frame will wait to be sent. The decision of which queue to use is based on
the classification of the frame.
The scheduling process, submits the queued frames for transmission.
Different algorithms can be used for emptying the different queues. For
example, Strict Priority, Weighted Round Robin, Deficit Round Robin
(DRR), or Modified Deficit Round Robin (MDRR). These algorithms are
further explained in section 6.3.1 on page 57.
The EDA access network uses as default a queue for network control, one
for voice, one for video and one for data. The default transport service and
traffic type for each classification is shown in Table 3 on page 53. All units
within the Ethernet Access Domain conform to the IEEE 802.1Q
specification.
Table 3 Ethernet QoS Mapping in EDA
Classification
(p-bit)
Priority Traffic Type
7 Highest Management
6 Higher Voice (Telephony over IP only)
5 High Video
0 - 4 Best Effort Data