C
LASS
OF
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ERVICE
C
ONFIGURATION
2-77
CLI – This example shows the switch configured with primary
VLAN 5 and secondary VLAN 6. Port 3 has been configured as a
promiscuous port and mapped to VLAN 5, while ports 4 and 5
have been configured as a host ports and associated with VLAN 6.
This means that traffic for port 4 and 5 can only pass through port
3.
Class of Service (CoS) allows data packets that have greater
precedence to receive higher service priority when traffic is
buffered in the switch due to congestion. This switch supports CoS
with four priority queues for each port. Data packets in a port’s
high-priority queues will be transmitted before those in the
lower-priority queues.
You can set the switch to service the queues based on a strict rule
that requires all traffic in a higher priority queue to be processed
before lower priority queues are serviced, or use Weighted
Round-Robin (WRR) queuing that specifies a relative weight for
each queue. WRR uses a predefined relative weight for each queue
that determines the percentage of service time the switch services
each queue before moving on to the next queue. This prevents the
head-of-line blocking that can occur with strict priority queuing
Console(config)#interface ethernet 1/3 3-89
Console(config-if)#switchport mode private-vlan promiscuous 3-136
Console(config-if)#switchport private-vlan mapping 5 3-138
Console(config-if)#exit
Console(config)#interface ethernet 1/4
Console(config-if)#switchport mode private-vlan host 3-136
Console(config-if)#switchport private-vlan host-association 6 3-137
Console(config-if)#exit
Console(config)#interface ethernet 1/5
Console(config-if)#switchport mode private-vlan host
Console(config-if)#switchport private-vlan host-association 6
Console(config-if)#