Administrator Guide

Figure 118. Single and Double-Tag TPID Mismatch
VLAN Stacking Packet Drop Precedence
VLAN stacking packet-drop precedence is supported on the switch.
The drop eligible indicator (DEI) bit in the S-Tag indicates to a service provider bridge which packets it should prefer to drop
when congested.
Enabling Drop Eligibility
Enable drop eligibility globally before you can honor or mark the DEI value.
When you enable drop eligibility, DEI mapping or marking takes place according to the defaults. In this case, the CFI is affected
according to the following table.
Table 104. Drop Eligibility Behavior
Ingress Egress DEI Disabled DEI Enabled
Normal Port Normal Port Retain CFI Set CFI to 0.
Service Provider Bridging 813