Packet Trust Level
The following figure illustrates how ICX series devices determine the trust level of a packet. As shown in the flowchart, the first criteria considered is whether the packet matches on an ACL that defines a priority. If this is not the case and the MAC address of the packet matches a static entry, the packet is classified with the priority of the static MAC entry. If neither of these is true, the packet is next classified with the ingress port default priority, then DSCP/ToS value, then IEE 802.1p CoS value, and finally the default priority of zero (0).
Once a packet is classified, it is mapped to a forwarding queue. There are eight queues designated from 0 through 7. The internal forwarding priority maps to one of these eight queues. The mapping between the internal priority and the forwarding queue cannot be changed.
The following tables show the default QoS mappings for ICX platforms that are used if the trust level for CoS or DSCP is enabled.
Default QoS Mappings for ICX Platforms, Columns 0 to 15
| DSCP value | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IEEE 802.1p (CoS) value | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Internal forwarding priority | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Forwarding queue | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Default QoS Mappings for ICX Platforms, Columns 16 to 31
Default QoS Mappings for ICX Platforms, Columns 32 to 47
Default QoS Mappings for ICX Platforms, Columns 48 to 63
Mapping between the DSCP value and forwarding queue cannot be changed. However, mapping between DSCP values and other properties can be changed as follows:
- DSCP to internal forwarding priority mapping—You can change the mapping between the DSCP value and the internal forwarding priority value from the default values shown in the above tables. This mapping is used for CoS marking and determining the internal priority when the trust level is DSCP. Refer to Changing the DSCP to Internal Forwarding Priority Mappings.
- VLAN priority (IEEE 802.1p) to hardware forwarding queue—You can change the mapping between the IEEE 802.1p value and hardware forwarding queue from the default value. Refer to Changing the VLAN Priority IEEE 802.1p to Hardware Forwarding Queue Mappings .