On Jan 17, 2019, at 4:56 PM, Florian Fainelli <[email protected]> wrote:
> These Ethernet adapters can be regular/normal Ethernet adapters, e.g:
> e1000e/igb/ixgbe on a PC connected to an Ethernet switch via GMII (for
> data path), and controlled by that PC through GPIO/SPI/I2C/MDIO for
> instance. If the switch is an external die/package then if you looked at
> frames between that NIC and the switch, you would see the tag, but that
> would require you snooping the wires between these two dies. If the
> switch is internal, things are not visible obviously.
>
> These Ethernet switch tags *never* go out to front-panel/RJ45
> connectors, they remain within the Ethernet switch logic and get
> processed internally and stripped, and then regular Ethernet frames go
> out these RJ45 connectors, a similar operation applies in the other
> direction (ingress).
OK, so it sounds as if:
1) the special ports on which the new DLT_ values would be used would
*always* get packets with the tags corresponding to the switch type, and would
*never* get regular Ethernet packets *or* DOCSIS packets from a Cisco CMTS
(Cable Modem Termination System);
2) regular Ethernet ports would *never* get packets with switch tags.
If so, that means that that:
1) the special ports should have only *one* DLT_ value - the one
corresponding to the switch type;
2) other Ethernet ports should just get DLT_EN10MB and DLT_DOCSIS.
> OK, then requesting 10 DLT values, one per-tag is reasonable?
Yes.
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