Alcatel-Lucent ls 6248 User Guide

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Configuring the Switch
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• Default CoS — Packets arriving untagged are assigned to a default VPT, which 
can be set by the user on a per port basis. Once the VPT is assigned, the packet 
is treated as if it had arrived with this tag. The VPT mapping to the output queue is 
based on the same user-defined 802.1p tag-based definitions.
• DSCP — The user can configure the system to use the IP DSCP of the incoming 
packet to the output priority queues. The mapping of the IP DSCP to priority queue 
is set on a per system basis. If this mode is active, a non-IP packet is always 
classified to the best effort queue. The default mapping is shown in the following 
table:
Table 3-6.  DSCP Default Mapping Table
All network traffic which is not assigned a DSCP value is forwarded with Best Effort 
service. 
After packets are assigned to a specific queue, using the chosen classification 
method various services can be applied. Scheduling for output queues can be 
configured, including: 
• Strict priority.
• Weighted Round Robin (WRR)
Scheduling schemes are specified per system. For each interface or queue, the 
following output shaping can also be configured: 
• Committed Information Rate (CIR)
QoS Modes
The device supports the following QoS modes: 
Basic  QoS  Mode
Advanced QoS Mode
Note:
When moving to and from basic and advanced QoS modes, some settings may be 
lost. 
Basic QoS Mode
Basic Mode supports activating one of the following Trust settings: 
VLAN Priority Tag
DiffServ Code Point
None
In addition, a single MAC-based or IP-based ACL can be attached directly to the 
interface (see Defining QoS Class Maps for more information). Only packets that 
DSCP Value
Queue Number 
0-15
q1 (Lowest Priority)
16-31
q2
32-47
q3
48-64
q4