From: Andrew Lunn <andrew@lunn•ch>
To: Ido Schimmel <idosch@mellanox•com>
Cc: Florian Fainelli <f.fainelli@gmail•com>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"davem@davemloft•net" <davem@davemloft•net>,
"vivien.didelot@gmail•com" <vivien.didelot@gmail•com>,
"cphealy@gmail•com" <cphealy@gmail•com>,
Jiri Pirko <jiri@mellanox•com>,
"bridge@lists•linux-foundation.org"
<bridge@lists•linux-foundation.org>,
"nikolay@cumulusnetworks•com" <nikolay@cumulusnetworks•com>,
"roopa@cumulusnetworks•com" <roopa@cumulusnetworks•com>,
"rdunlap@infradead•org" <rdunlap@infradead•org>,
"ilias.apalodimas@linaro•org" <ilias.apalodimas@linaro•org>,
"ivan.khoronzhuk@linaro•org" <ivan.khoronzhuk@linaro•org>
Subject: Re: [PATCH net-next v4] Documentation: networking: Clarify switchdev devices behavior
Date: Fri, 11 Jan 2019 16:43:31 +0100 [thread overview]
Message-ID: <20190111154331.GE20924@lunn.ch> (raw)
In-Reply-To: <20190111150637.GA897@splinter.mtl.com>
> > +IGMP snooping
> > +~~~~~~~~~~~~~
> > +
> > +The Linux bridge allows the configuration of IGMP snooping (compile and run
> > +time) which must be observed by the underlying switchdev network device/hardware
> > +in the following way:
> > +
> > +- when IGMP snooping is turned off, multicast traffic must be flooded to all
> > + switch ports within the same broadcast domain. The CPU/management port
> > + should ideally not be flooded and continue to learn multicast traffic through
> > + the network stack notifications. If the hardware is not capable of doing that
> > + then the CPU/management port must also be flooded and multicast filtering
> > + happens in software.
> > +
> > +- when IGMP snooping is turned on, multicast traffic must selectively flow
> > + to the appropriate network ports (including CPU/management port) and not flood
> > + the switch.
> > +
> > +Note: reserved multicast addresses (e.g.: BPDUs) as well as Local Network
> > +Control block (224.0.0.0 - 224.0.0.255) do not require IGMP and should always
> > +be flooded.
>
> I'm not sure that these paragraphs are actually needed. You're basically
> describing RFC 4541 on which the IGMP snooping functionality in the
> Linux bridge is based on.
Hi Ido
My experience talking with people is that IGMP snooping is a bit
mystical and not well understood. I would not be surprised if
community driver writers, as opposed to vendor driver writers, don't
actually know how snooping works. So i find having some hints is good.
Andrew
next prev parent reply other threads:[~2019-01-11 15:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 19:32 [PATCH net-next v4] Documentation: networking: Clarify switchdev devices behavior Florian Fainelli
2019-01-10 21:50 ` Randy Dunlap
2019-01-10 21:50 ` Randy Dunlap
2019-01-11 15:06 ` Ido Schimmel
2019-01-11 15:06 ` Ido Schimmel
2019-01-11 15:43 ` Andrew Lunn [this message]
2019-01-11 15:43 ` Andrew Lunn
2019-01-11 15:53 ` Ido Schimmel
2019-01-11 15:53 ` Ido Schimmel
2019-01-11 18:34 ` Florian Fainelli
2019-01-11 18:34 ` Florian Fainelli
2019-01-11 19:20 ` Ido Schimmel
2019-01-11 19:20 ` Ido Schimmel
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