On Thu, Dec 30, 2021 at 09:04:53PM +0100, Christopher Zimmermann wrote:
> On Mon, Dec 20, 2021 at 04:41:07PM -0700, Theo de Raadt wrote:
> >You say it twice.  But my eyes still glazed over it, not seeing what 
> >was going on the first two times.
> >
> >Maybe something more like
> >
> >      prio 0 and 1 are mapped out of order to PCP 1 and 0, but prio 2 to
> >      7 are mapped directly to PCP 2 to 7.
> >
> >No that still doesn't quite capture it in a visible way. How about
> >
> >      prio 2 to 7 are mapped directly to PCP 2 to 7, but prio 0 and 1
> >      are mapped backwards, to PCP 1 and 0, because <.......>
> >
> >Something which will draw the eye+brain to 'something is different here'.
> >The table alone doesn't do that.
> 
> I agree. How about this?
> 
>       The 802.1Q and 802.1ad protocols include a Priority Code Point (PCP).  
> By
>       default, the 802.1p PCP in a transmitted packet is based on the priority
>       of packets sent over the interface, which may be altered via pf.conf(5);
>       see the prio option for more information.  Alternatively, the 
> ifconfig(4)
>       txprio option can set a specific priority for transmitted packets. On
>       vlan and svlan interfaces priorities 2 to 7 will be mapped directly to
>       PCP 2 to 7, but priorities 0 and 1 are mapped backwards, to PCP 1 and 0.
>       This is because 802.1p defines PCP 1 as lowest priority and PCP 0 as
>       second lowest priority, which is meant to be used as default (???best
>       effort???).
> 

hi.

some feedback, inline.

> 
> Index: vlan.4
> ===================================================================
> RCS file: /cvs/src/share/man/man4/vlan.4,v
> retrieving revision 1.51
> diff -u -p -r1.51 vlan.4
> --- vlan.4    4 Oct 2020 12:44:49 -0000       1.51
> +++ vlan.4    30 Dec 2021 20:00:38 -0000
> @@ -83,17 +83,26 @@ interfaces by their respective protocol 
>   identifiers, and decapsulated for reception on the associated virtual
>   interfaces.
>   .Pp
> -The 802.1Q and 802.1ad protocols include a priority field.
> -By default, the 802.1p priority in a transmitted packet is based on the
> +The 802.1Q and 802.1ad protocols include a Priority Code Point (PCP).
> +By default, the 802.1p PCP in a transmitted packet is based on the
>   priority of packets sent over the interface, which may
>   be altered via
>   .Xr pf.conf 5 ;
>   see the
>   .Cm prio
>   option for more information.
> -Alternatively,
> +Alternatively, the
> +.Xr ifconfig 4
>   .Cm txprio
> -can set a specific priority for transmitted packets.
> +option can set a specific priority for transmitted packets. On

you should start new sentences on new lines

> +.Nm vlan
> +and
> +.Nm svlan
> +interfaces priorities 2 to 7 will be mapped directly to PCP 2 to 7, but
> +priorities 0 and 1 are mapped backwards, to PCP 1 and 0. This is because

ditto

also, consider s/and 0/and 0, respectively/
it is more explicit (which seems to be relevant here)

> +802.1p defines PCP 1 as lowest priority and PCP 0 as second lowest
> +priority, which is meant to be used as default

i'm having trouble with the lack of a/the here. i don;t know the subject
matter well enough to say exactly what it should be, but:

        as lowest priority -> as the lowest priority
        as second -> as the second
        as default -> as the default

(not sure, just asking)

> +.Pq Dq best effort .

i would not mark this up i.e. use ("best effort")

jmc

>   .Pp
>   .Nm vlan
>   and

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