Administrator Guide

Figure 101. Single and Double-Tag TPID Mismatch
VLAN Stacking Packet Drop Precedence
VLAN stacking packet drop precedence is available on the Z9000 platform.
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.
Service Provider Bridging
745