OmniSwitch os6900 Network Configuration Manual page 672

Using Access Control Lists
Layer 2 ACL: Example 2
Maintaining the 802.1p Priority for IP Packets
When a tagged IP packet ingresses on a trusted port and the default classification priority for that port is
set to DSCP (using the default DSCP value of 0), the DSCP value of the packet is mapped to the 802.1p
value of the same packet. To avoid overwriting the 802.1p value in this scenario, configure an ACL as
follows:
1
Create a port group to include all of the ports that QoS must trust.
2
Define policy conditions for the port group; one condition for each L2 priority (802.1p) value.
3
Define policy actions that stamp the IP traffic with the L2 priority value.
4
Define policy rules using the conditions and actions created in Steps 2 and 3.
5
Do not globally trust all switch ports.
For example:
-> policy port group VoIP 1/4-6 1/8 2/3-5
-> policy condition p0 destination port group VoIP
-> policy condition p1 destination port group VoIP
-> policy condition p2 destination port group VoIP
-> policy condition p3 destination port group VoIP
-> policy condition p4 destination port group VoIP
-> policy condition p5 destination port group VoIP
-> policy condition p6 destination port group VoIP
-> policy condition p7 destination port group VoIP
-> policy action p0 802.1p 0
-> policy action p1 802.1p 1
-> policy action p2 802.1p 2
-> policy action p3 802.1p 3
-> policy action p4 802.1p 4
-> policy action p5 802.1p 5
-> policy action p6 802.1p 6
-> policy action p7 802.1p 7
-> policy rule p0 condition p0 action p0
-> policy rule p1 condition p1 action p1
-> policy rule p2 condition p2 action p2
-> policy rule p3 condition p3 action p3
-> policy rule p4 condition p4 action p4
-> policy rule p5 condition p5 action p5
-> policy rule p6 condition p6 action p6
-> policy rule p7 condition p7 action p7
-> qos apply
Note. For pure Layer 2 packets, trusted ports retain the 802.1p value of the packet and queue the packets
according to that priority value.
page 25-64 OmniSwitch AOS Release 7 Network Configuration Guide
Configuring QoS
June 2013