82598EB Datasheet, PDF (532/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Advanced Workflows
To accomplish this, NC-SI provides the following:
1. Enable Network Tx command. This command enables shutting off the network transmit path of a
specific channel. This enables the MC to configure all the participating channels with the same MAC
address but only enable one of them.
2. Link Status Change AEN or Get Link Status command.
5.4.5.3.1 Fail-Over Algorithm Example
Following is a sample workflow for a fail-over scenario for 82598EB dual-port GbE controller (one
package and two channels).
1. MC initializes and configures both channels after power-up. However, the MC uses the same MAC
address for both of the channels.
2. The MC queries the link status of all the participating channels. The MC should continuously monitor
the link status of these channels. This can be accomplished by listening to AENs (if used) and/or
periodically polling using the Get Link Status command.
3. The MC then only enables channel 0 for network transmission.
4. The MC then issues a gratuitous ARP (or any other packet with its source MAC address) to the
network. This packet informs the switch that this specific MAC address is registered to channel 0's
specific LAN port.
5. The MC begins normal workflow.
6. Should the MC receive an indication (AEN or polling) that the link status for the active channel
(channel 0) has changed, the MC should:
a. Disable channel0 for Network Transmission.
b. Check if a different channel is available (link is up).
If found:
Enable network Tx for that specific channel.
Issue a gratuitous ARP (or any other packet with its source MAC address) to the network. This
packet informs the switch that this specific MAC address is registered to channel 0's specific LAN
port.
Resume normal workflow.
If not found, report the error and continue polling until a valid channel is found.
Note: The above algorithm can be generalized such that the start-up and normal workflow are the
same.
In addition, the MC might need to use a specific channel (such as channel 0). In this case, the MC
should switch the network transmit to that specific channel as soon as that channel becomes valid (link
is up).
Recommendations:
• It is recommended to wait a link-down-tolerance timeout before a channel is considered invalid.
For example, a link re-negotiation might take a few seconds (normally 2 to 3 or might be up to
9). Thus, the link must be re-established after a short time.
• Typically, this timeout is recommended to be three seconds.
• Even when enabling and using AENs, it is still recommended to periodically poll the link status, as
dropped AENs might not be detected.
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