Messages in this thread | | | Subject | Re: [PATCH net-next 16/17] Documentation: networking: dsa: Add details about NXP SJA1105 driver | From | Vladimir Oltean <> | Date | Wed, 3 Apr 2019 13:09:29 +0300 |
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On 4/3/19 12:24 AM, Andrew Lunn wrote: >> +The switches do not support switch tagging in hardware. But they do support >> +customizing the TPID by which VLAN traffic is identified as such. The switch >> +driver is leveraging CONFIG_NET_DSA_TAG_8021Q by requesting that special VLANs >> +(with a custom TPID of ETH_P_EDSA instead of ETH_P_8021Q) > > Hi Vladimir > > Reusing ETH_P_EDSA is possibility going to case problems in tcpdump. > It has code which looks for this Ethertype and uses it to call the > Marvell EDSA header decoder code. This is not going to work for your > switch, where you have a normal VLAN header. > > I wounder if we should allocate a new EtherType for this application > of VLANs? > > Andrew >
Hi Andrew,
This makes me wonder whether I would be able to use an EtherType range to support cascading switch tags on SJA1105. In theory if I were to consistently lie to all switches within a switch tree, I could make all of them see each other's fake VLAN-tagged traffic as untagged. By the way what is the simple ETH_P_DSA used for?
Thank you, -Vladimir
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