Load Distribution to Multiple Servers via Switch

Received traffic can be distributed to the host as well as multiple servers using the Action command in combination with the Assign command. The following NTPL example shows how to configure the SmartNIC to distribute frames to the host as well as to another server at the same time.

HashMode[Priority = 1; Layer3Type=IP] = Hash2TupleSorted
HashMode[Priority = 0; Layer3Type=IP; Layer4Type=TCP,UDP,SCTP] = Hash5TupleSorted

Action[Tag=example; Width=24]={Index=0..11; StreamID=0..11},{Index=12..23; DestinationPort=1}
Assign[Action=example]=Port==0

The Width parameter specifies the number of indices which are used for dividing the received traffic. The load distribution is configured by associating indices to streams in the host and associating indices to physical ports. In this NTPL example, the first 12 out of 24 indices are associated to streams in the host, and the last 12 indices are associated to port 1.

In the figure, all received frames are distributed to the host and 3 other servers. All received frames will obtain 3 VLAN tags (101, 102 and 103) and will be transmitted on port 1. See an NTPL example below.

HashMode[Priority = 1; Layer3Type=IP] = Hash2TupleSorted
HashMode[Priority = 0; Layer3Type=IP; Layer4Type=TCP,UDP,SCTP] = Hash5TupleSorted

Action[Tag=vlan_example; Width=16] = {Index=0..3; StreamId=0..3}, {Index=4..15; DestinationPort=1; Vlan=101..103} 
Assign[Action=vlan_example] = All

In this NTPL example, The first 4 out of 16 indices are associated to 4 streams in the host, and the last 12 indices are associated to port 1.

Frames can be distributed to multiple servers based on the VLAN ranges as shown in the following figure.

The received frames in each server can be distributed and processed in multiple CPU cores using VLAN tags if the networking device capable of receive side scaling (RSS) is used in the system, for example. See an NTPL example below.

HashMode[Priority = 1; Layer3Type=IP] = Hash2TupleSorted
HashMode[Priority = 0; Layer3Type=IP; Layer4Type=TCP,UDP,SCTP] = Hash5TupleSorted

Action[Tag=vlan_example; Width=12] = {Index=0..3; StreamId=0..3}, {Index=4..11; DestinationPort=1; Vlan=101..108} 
Assign[Action=vlan_example] = All

Adding VLAN TPIDs is supported in addition to adding VLAN tags. The following NTPL example shows how to add a VLAN TPID.

HashMode[Priority = 1; Layer3Type=IP] = Hash2TupleSorted
HashMode[Priority = 0; Layer3Type=IP; Layer4Type=TCP,UDP,SCTP] = Hash5TupleSorted

Action[Tag=vlan_example; VlanTpid=0x9100; Width=8] = {Index=0..7; StreamId=0..3}, \\
{Index=0..7; DestinationPort=1; Vlan=101..108}
Assign[Action=vlan_example] = All