Data Sheet

Ethernet Controller I210 —Inline Functions
260
2. A hash calculation is performed. The I210 supports a single hash function, as defined by Microsoft*
RSS. The I210 does not indicate to the software device driver which hash function is used. The 32-
bit result is fed into the packet receive descriptor.
3. The seven LSB bits of the hash result are used as an index into a 128-entry indirection table. Each
entry provides a 3-bit RSS output index.
When RSS is disabled, packets are assigned an RSS output index = zero. System software might
enable or disable RSS at any time. While disabled, system software might update the contents of any of
the RSS-related registers.
When multiple requests queues are enabled in RSS mode, un-decodable packets are assigned an RSS
output index = zero. The 32-bit tag (normally a result of the hash function) equals zero.
Figure 7-6. RSS Block Diagram
RSS Hash
LS
Packet
Descriptor
Parsed
Receive
Packet
7
32
RSS Disable or (RSS
And Not Decodable)
3
0
3
RSS Output Index
Indirection Table
128 x 3