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

[Xiaoliang Yang]

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.

Thanks,
Xiaoliang