2.3.1 Communication method

There are two communication methods used for the virtual NIC mode: "Active-Standby" mode and "MAC Tracking" mode.

"Active-Standby" mode

One of the grouped NICs is used exclusively to carry out the communication.

"MAC Tracking" mode

When an error is detected by the network monitoring, use all NICs at the same time to carry out the communication. In MAC Tracking, source MAC addresses and NICs which received packets learn when receiving packets from the remote system. When sending packets to the remote system, select an appropriate NIC based on the learning result.

Moreover, when the application sends packets to a destination of a broadcast or multicast address, use all NICs to send packets.

Destination MAC address	Selection of sending NICs
MAC address corresponding to the destination have not learned or the destination address is broadcast/ multicast	Send packets by using all NICs. The following two modes can be selected as MAC Tracking: Broadcast Duplicate packets and send them from all NICs simultaneously. Round-robin Distribute NICs evenly and send packets. For details, see "A.1 rvnetadm command."
MAC address corresponding to the destination has already learned	Based on the learning result, select the sending NICs and send packets.

Destination MAC address

Selection of sending NICs

MAC address corresponding to the destination have not learned
or
the destination address is broadcast/ multicast

Send packets by using all NICs.
The following two modes can be selected as MAC Tracking:

Broadcast
Duplicate packets and send them from all NICs simultaneously.
Round-robin
Distribute NICs evenly and send packets.

For details, see "A.1 rvnetadm command."

MAC address corresponding to the destination has already learned

Based on the learning result, select the sending NICs and send packets.

The following shows the example of sending procedure when a connection between switches fails and the network is disconnected. Right after the network failure, the communication used for the virtual NIC is sent from both NIC1 and NIC2. Then, after receiving the response from the remote system, it learns the MAC address of the remote system and packets are transmitted via only reachable paths.

Figure 2.8 "MAC Tracking" mode