Re: [EXT] Re: [RFC, net-next] net: qos: introduce a frer action to implement 802.1CB

[Vladimir Oltean]

Hi Vinicius,

On Wed, Sep 29, 2021 at 10:25:58AM +0000, Xiaoliang Yang wrote:
> Hi Vinicius,
>
> On Sep 29, 2021 at 6:35:59 +0000, Vinicius Costa Gomes wrote:
> > > This patch introduce a frer action to implement frame replication and
> > > elimination for reliability, which is defined in IEEE P802.1CB.
> > >
> >
> > An action seems, to me, a bit too limiting/fine grained for a frame replication
> > and elimination feature.
> >
> > At least I want to hear the reasons that the current hsr/prp support cannot be
> > extended to support one more tag format/protocol.
> >
> > And the current name for the spec is IEEE 802.1CB-2017.
> >
> 802.1CB can be set on bridge ports, and need to use bridge forward
> Function as a relay system. It only works on identified streams,
> unrecognized flows still need to pass through the bridged network
> normally.
>
> But current hsr/prp seems only support two ports, and cannot use the
> ports in bridge. It's hard to implement FRER functions on current HSR
> driver.
>
> You can see chapter "D.2 Example 2: Various stack positions" in IEEE 802.1CB-2017,
> Protocol stack for relay system is like follows:
>
>              Stream Transfer Function
>                 |             |
>                 |        Sequence generation
>                 |            Sequence encode/decode
>   Stream identification        Active Stream identification
>                 |              |
>                 |        Internal LAN---- Relay system forwarding
>                 |                        |        |
>                 MAC                    MAC        MAC
>
> Use port actions to easily implement FRER tag add/delete, split, and
> recover functions.
>
> Current HSR/PRP driver can be used for port HSR/PRP set, and tc-frer
> Action to be used for stream RTAG/HSR/PRP set and recover.

Did Xiaoliang answer your question satisfactorily? :)