82598EB Datasheet, PDF (212/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Receive Functionality
Section 3.5.2.10.3 for more details on VMDq.
Table 3-47. Supported Modes for Allocation of Receive Descriptor Queues
VMDq
Off
On
Single Packet Buffer
Off
Supported
Supported
RSS
On
Supported
Supported
Since the 82598 provides a total of 64 receive descriptor queues, a received packet is assigned a 6-bit
queue index. Each of RSS and VMDq determines the value of some bits in the queue index:
• RSS provides a 4-bit RSS output index. Queue allocation can use of four bits or just some LSB of
it. RSS assigns an RSS output index equal to zero for traffic that does not go through RSS.
Depending on the configuration of VMDq/RSS, such traffic might end up in one of several queues.
• VMDq provides a 4-bit VMDq output index. Queue allocation can make use of four bits or just
some LSB of it.
Generating a 6-bit queue index from the RSS and VMDq indices is defined in Table 3-48 and the notes
that follow it.
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