Quality of Service
General
420
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
23
CoS/802.1p to a Queue
The CoS/802.1p to Queue page maps 802.1p priorities to egress queues. The CoS/802.1p to
Queue Table determines the egress queues of the incoming packets based on the 802.1p
priority in their VLAN Tags. For incoming untagged packets, the 802.1p priority is the default
CoS/802.1p priority assigned to the ingress ports.
The following table describes the default mapping when there are 8 queues:
By changing the CoS/802.1p to Queue mapping (CoS/802.1p to Queue) and the Queue
schedule method and bandwidth allocation (Queue page), it is possible to achieve the desired
quality of service in a network.
The CoS/802.1p to Queue mapping is applicable only if one of the following exists:
•
The device is in QoS Basic mode and CoS/802.1p trusted mode
•
The device is in QoS Advanced mode and the packets belong to flows that are CoS/
802.1p trusted
802.1p Values
(0-7, 7 being the
highest)
Queue
(8 queues 1-8, 8
is the highest
priority)
7 Queues
(8 is the highest
priority used for
stack control traffic)
Stack
Notes
0
1
1
Background
1
2
1
Best Effort
2
3
2
Excellent Effort
3
6
5
Critical Application - LVS
phone SIP
4
5
4 Video
5
8
7
Voice - Cisco IP phone
default
6
8
7
Interwork Control
LVS phone RTP
7
7
6
Network Control