From: Stephen Hemminger <stephen@networkplumber.org>
To: Jonathan Morton <chromatix99@gmail.com>
Cc: Davide Caratti <dcaratti@redhat.com>,
cake@lists.bufferbloat.net, netdev@vger.kernel.org,
David Miller <davem@davemloft.net>
Subject: Re: [Cake] [PATCH net-next 1/5] sch_cake: fix IP protocol handling in the presence of VLAN tags
Date: Fri, 26 Jun 2020 15:00:59 -0700 [thread overview]
Message-ID: <20200626150059.785647cb@hermes.lan> (raw)
In-Reply-To: <78C16717-5EB2-49BF-A377-21A9B22662E1@gmail.com>
On Fri, 26 Jun 2020 16:11:49 +0300
Jonathan Morton <chromatix99@gmail.com> wrote:
> Toke has already replied, but:
>
> > Sure, my proposal does not cover the problem of mangling the CE bit inside
> > VLAN-tagged packets, i.e. if we should understand if qdiscs should allow
> > it or not.
>
> This is clearly wrong-headed by itself.
>
> Everything I've heard about VLAN tags thus far indicates that they should be *transparent* to nodes which don't care about them; they determine where the packet goes within the LAN, but not how it behaves. In particular this means that AQM should be able to apply congestion control signals to them in the normal way, by modifying the ECN field of the IP header encapsulated within.
>
> The most I would entertain is to incorporate a VLAN tag into the hashes that Cake uses to distinguish hosts and/or flows. This would account for the case where two hosts on different VLANs of the same physical network have the same IP address.
>
> - Jonathan Morton
>
> _______________________________________________
> Cake mailing list
> Cake@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cake
The implementation of VLAN's is awkward/flawed. The outer VLAN tag is transparent
but the inner VLAN is visible. Similarly the outer VLAN tag doesn't count towards
the MTU but inner one does.
next prev parent reply other threads:[~2020-06-26 22:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 11:55 [PATCH net-next 0/5] sched: A series of fixes and optimisations for sch_cake Toke Høiland-Jørgensen
2020-06-25 11:55 ` [PATCH net-next 1/5] sch_cake: fix IP protocol handling in the presence of VLAN tags Toke Høiland-Jørgensen
2020-06-25 19:29 ` David Miller
2020-06-25 19:53 ` Toke Høiland-Jørgensen
2020-06-25 20:00 ` David Miller
2020-06-26 8:27 ` Davide Caratti
2020-06-26 12:52 ` [Cake] " Toke Høiland-Jørgensen
2020-06-26 14:01 ` Jamal Hadi Salim
2020-06-26 18:52 ` Davide Caratti
2020-06-29 10:27 ` Toke Høiland-Jørgensen
2020-06-26 13:11 ` Jonathan Morton
2020-06-26 22:00 ` Stephen Hemminger [this message]
2020-06-25 11:55 ` [PATCH net-next 2/5] sch_cake: don't try to reallocate or unshare skb unconditionally Toke Høiland-Jørgensen
2020-06-25 11:55 ` [PATCH net-next 3/5] sch_cake: don't call diffserv parsing code when it is not needed Toke Høiland-Jørgensen
2020-06-25 11:55 ` [PATCH net-next 4/5] sch_cake: add RFC 8622 LE PHB support to CAKE diffserv handling Toke Høiland-Jørgensen
2020-06-25 11:55 ` [PATCH net-next 5/5] sch_cake: fix a few style nits Toke Høiland-Jørgensen
2020-06-25 19:31 ` [PATCH net-next 0/5] sched: A series of fixes and optimisations for sch_cake David Miller
2020-06-25 19:49 ` Toke Høiland-Jørgensen
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