VLAN Translation - 7.2 English

AXI 1G/2.5G Ethernet Subsystem Product Guide (PG138)
Document ID
PG138
Release Date
2023-11-15
Version
7.2 English

VLAN translation enables the AXI Ethernet Subsystem to replace the VLAN ID (VID) value of the VLAN Tag field of a VLAN frame with a new VID as it passes through the subsystem in either the transmit or receive direction. See the following figure.

Figure 1. VLAN VID Translation AXI Ethernet Page-1 Sheet.2 Sheet.3 Sheet.4 Sheet.5 Sheet.6 Sheet.7 Sheet.8 Sheet.9 Sheet.10 Sheet.11 Sheet.12 Sheet.13 Sheet.14 Sheet.15 Sheet.16 Sheet.17 Sheet.18 Sheet.19 Sheet.20 Sheet.21 Sheet.22 Sheet.23 Sheet.24 Sheet.25 Sheet.26 Sheet.46 VLAN tag 4 bytes VLAN tag4 bytes Sheet.1 6 bytes 6bytes Sheet.28 Type /Len Type/Len Sheet.29 FCS FCS Sheet.30 Data Data Sheet.31 TPID 8100 9100 9200 88a8 TPID81009100920088a8 Sheet.33 CFI CFI Sheet.34 46 - 1500 bytes normal 46 - 9198 bytes jumbo 46 - 1500 bytes normal 46 - 9198 bytes jumbo Sheet.35 Dest Addr DestAddr Sheet.36 Srce Addr Srce Addr Sheet.37 6 bytes 6bytes Sheet.38 2 bytes 2bytes Sheet.40 3 bytes 3bytes Sheet.39 VID xxx VIDxxx Sheet.41 Priority Priority Sheet.42 1 bit 1bit Sheet.43 12 bits 12bits Sheet.44 2 bytes 2bytes Sheet.45 4 bytes 4bytes Sheet.47 Type /Len Type/Len Sheet.48 FCS FCS Sheet.49 Data Data Sheet.50 TPID 8100 9100 9200 88a8 TPID81009100920088a8 Sheet.51 CFI CFI Sheet.52 Dest Addr DestAddr Sheet.53 Srce Addr Srce Addr Sheet.54 VID yyy VIDyyy Sheet.55 Priority Priority Standard Arrow Standard Arrow.57 Standard Arrow.58 Standard Arrow.59 Standard Arrow.20 Sheet.62 Sheet.27 X14088 X14088 Side brace

The TEMAC core recognizes neither transmission nor reception. VLAN frames with a TPID other than 0x8100 when VLAN mode is enabled. If VLAN mode is disabled, then the maximum length of a normal frame is not extended from 1,518 to 1,522 bytes. Additionally, multiple tagging is also not supported because of the even larger frame sizes.

To support multiple VLAN tagging and the use of TPID values other than 0x8100 in the outer tag, jumbo frame mode must be used with basic VLAN mode disabled. Using this setting eliminates automatic invalidating (by the TEMAC core) of any frames that would be too large for normal frame sizes. To use extended VLAN mode, you must enable jumbo frame mode and disable VLAN mode.