Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 897

TPID 0x8100 on E-Series TeraScale Systems E-Series TeraScale treats TPID 0x8100 as a normal VLAN even when on the outer tag. E-Series TeraScale makes forwarding decisions based strictly on the protocol type, without regard for whether the port is an access port. Therefore, when the outer tag has TPID 0x8100, the system does not remove it from frames egressing an access port. Still, although the frames cannot be decapsulated, the system is able to switch them. In Figure 49-4, the frame originating from Building A is double tagged on egress at R4 and is switched towards Building B, but is not decapsulated on egress at R2 because its TPID is 0x8181. FTOS Behavior: The E-Series ExaScale and TeraScale forward frames with TPID 0x8100 even when its own TPID is not 0x8100. This behavior is required to service ARP and PVST packets, which use TPID 0x8100. Figure 49-4. TPID Mismatch and 0x8100 Match on the E-Series TeraScale INTERNET VLAN BLUE SERVICE PROVIDER TPID 0x9100 VLAN BLUE X VLAN GREEN R2-E-Series TeraScale TPID: 0x8181 R1-E-Series TeraScale TPID: 0x9100 VLAN GREEN, VLAN PURPLE VLAN PURPLE Building D TPID 0x8100 VLAN RED X R3-E-Series TeraScale TPID: 0x8181 TPID PCP CFI (0x8100) (0) Building B VID TPID PCP (VLAN Purple) (0x8100) Building C R4-Non-Force10 System TPID: 0x8100 TPID PCP (0x8100) CFI VID (0) (VLAN Red) CFI VID (0) (VLAN Red) VLAN RED Building A VLAN Stacking with E-Series ExaScale Systems E-Series ExaScale, beginning with FTOS version 8.2.1.0, allows you to configure both bytes of the 2-byte TPID. TeraScale systems allow you to configure the first byte only and thus, the system did not differentiate between TPIDs with a common first byte. For example 0x9100 and 0x91A8 were treated as the same TPID. In Figure 49-3, R2 forwards the frame with TPID 0x9191 which originated from Building C. In contrast, R2 drops the frame with TPID 0x9191 originating from Building C in Figure 49-5 because the frames TPID does not match both bytes of its own TPID. Service Provider Bridging | 897