Re: Requesting DLT_* values for Ethernet switches proprietary tagging protocol

[Florian Fainelli <f.fainelli () gmail com>]

Le 1/17/19 à 5:24 PM, Guy Harris a écrit :
> On Jan 17, 2019, at 4:56 PM, Florian Fainelli <f.fainelli () gmail com> 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.

Correct. The other ports are exposed as regular Ethernet network devices.

> > OK, then requesting 10 DLT values, one per-tag is reasonable?
>
> Yes.

I see that you answered on the pull request that I pasted the link for,
thanks for doing that.

Cheers
-- 
Florian
_______________________________________________
tcpdump-workers mailing list
tcpdump-workers () lists tcpdump org
https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers