Layer 3 Ethernet framing
Word# | Word's BYTE | Type | Name | Description | Note |
---|---|---|---|---|---|
0 | [5:0] | Header | DestMac | Destination MAC |
|
0 | [11:6] | Header | SrcMac | Source MAC |
|
0 | [13:12] | Header | EtherType | TBD Value |
|
0 | 14 | Header | Version | 0x1 |
|
0 | 15 | Header | TID | Transaction ID |
|
0 | [17:16] | Header | Pause | Virtual Channel Pause |
|
0 | 18 | Header | VC | Virtual Channel Index |
|
0 | 19 | Header | tUserFirst | first 8-bits of tUser | |
0 | 20 | Header | OpCodeEn | OP-code Enable | |
0 | [29:20] | Header | Reserved | Reserved |
|
0 | [31:30] | Header | HdrXsum | 16-bit Header Checksum |
|
0 | [47:32] | Header | OpCodeData | 128-bit OP-code Data |
|
0 | [63:48] | Header | UserData | 128-bit User Data |
|
1 | [63:0] | Payload | AXIS Data | User Payload Data | |
... | ... | ... | ... | ... | |
(MAX_SIZE/64) | [63:0] | Payload | AXIS Data | User Payload Data | |
(MAX_SIZE/64)+1 | 0 | Footer | tKeepLast | TKEEP on last payload word |
|
(MAX_SIZE/64)+1 | 1 | Footer | EOF/EOFE | EOF and EOFE marker |
|
(MAX_SIZE/64)+1 | [3:2] | Footer | Pause | Virtual Channel Pause |
|
(MAX_SIZE/64)+1 | [5:4] | Footer | PayloadSize | Number of bytes in payload |
|
Going "point-to-point" we were measuring 97.3 Gb/s bandwidth for 1MB frames using 8196B HTSP burst size. 97.3 Gb/s is < 98.9% theoretical limit, which we think is related to some unaccounted inefficiency in the CMAC4 hard IP core that we used in this testing. The DMA bandwidth limit in this test was 101 Gb/s, which means the DMA was not back pressuring on the HTSP link. Auto-polling register channel access on the HTSP link on a different virtual channel was enabled in this testing.