Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.112.0P1 - Page 817

Network Position Core Incoming Packet TPID untagged System TPID 0xUVWX double-tag 0xUVWX 0xUVWX 0xUVYZ 0xQRST Egress Access Point untagged 0xUVWX double-tag 0xUVWX 0xUVWX 0xUVYZ 0xQRST Match Type Pre-Version 8.2.1.0 Version 8.2.1.0+ - switch to default VLAN double-tag match switch to VLAN double-tag first-byte switch to VLAN match double-tag mismatch switch to default VLAN - switch to default VLAN double-tag match switch to VLAN double-tag first-byte switch to VLAN match double-tag mismatch switch to default VLAN switch to default VLAN switch to VLAN switch to default VLAN switch to default VLAN switch to default VLAN switch to VLAN switch to default VLAN switch to default VLAN 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 87. Drop Eligibility Behavior Ingress Egress Normal Port Normal Port Trunk Port Trunk Port Access Port Trunk Port DEI Disabled Retain CFI Retain inner tag CFI Retain outer tag CFI Retain inner tag CFI Set outer tag CFI to 0 DEI Enabled Set CFI to 0. Retain inner tag CFI. Set outer tag CFI to 0. Retain inner tag CFI Set outer tag CFI to 0 To enable drop eligibility globally, use the following command. • Make packets eligible for dropping based on their DEI value. CONFIGURATION mode dei enable By default, packets are colored green, and DEI is marked 0 on egress. Service Provider Bridging 817