Creating a policy based on the VLAN-ID
Example:
vlan vid qos dscp codepoint
Assigns a DSCP policy to IP packets carrying the specified VLAN ID, and overwrites the DSCP in these packets with the assigned
codepoint
value.
A binary value for the six-bit codepoint from
000000
to111111
.A decimal value from
0
(low priority) to63
(high priority) that corresponds to a binary DSCP bit setAn ASCII standard name for a binary DSCP bit set. Enter
?
to display the list of valid codepoint entries.The DSCP policy includes an 802.1p priority and determines the packet's queue in the outbound port to which it is sent. If the packet leaves the switch on a tagged port, it carries the 802.1p priority with it to the next downstream device.Default: No-override
Syntax:
no vlan vid qos
Removes a global QoS classifier for the specified VLAN.
Syntax:
show qos vlan-priority
Displays a listing of all QoS VLAN-ID classifiers currently in the
running-config
file.See: example.
Determine if the DSCP codepoints that you want to use to remark packets already have an 802.1p priority assigned, which could indicate use by existing applications (
show qos dscp-map
command)
. This is not a problem as long as the configured priorities are acceptable for all applications using the same DSCP.- A DSCP codepoint must also have a priority configured before you can use it to mark matching packets.
- Configure the priorities for the DSCPs.
- Assign the DSCP policies to the selected VLAN IDs and display the result.
switch(config)# vlan 1 qos dscp 000010 switch(config)# vlan 20 qos dscp 000010 switch(config)# vlan 30 qos dscp 000101 switch(config)# vlan 40 qos dscp 000111 switch(config)# show qos vlan-priority VLAN priorities VLAN ID Apply rule | DSCP Priority ------- ----------- + ------ ----------- 1 DSCP | 000010 1 20 DSCP | 000010 1 30 DSCP | 000101 5 40 DSCP | 000111 7
Overwrite the original DSCPs in the selected packets with the new DSCPs specified in the above policies.
Assign the 802.1p priorities in the above policies to the appropriate packets.
Assigning DSCP policies to packets
VLAN-ID |
DSCP |
Priority |
---|---|---|
40 |
000111 |
7 |
30 |
000101 |
5 |
20 |
000010 |
1 |
1 |
000010 |
1 |