Re: [PATCH 2.6.33 1/3] net: Micrel KSZ8841/2 PCI Ethernet driver
From: Stephen Hemminger
Date: Tue Jan 19 2010 - 19:50:58 EST
On Tue, 19 Jan 2010 16:34:38 -0800
"Ha, Tristram" <Tristram.Ha@xxxxxxxxxx> wrote:
> Stephen Hemminger wrote:
> > On Tue, 19 Jan 2010 15:48:50 -0800
> > "Ha, Tristram" <Tristram.Ha@xxxxxxxxxx> wrote:
> >> Stephen Hemminger wrote:
> >>>> Now for the driver implementation for STP support. I programmed
> >>>> the switch's static MAC table to always pass the following frames
> >>>> to the
> >>>> host: BPDU frames with specific multicast address, broadcast
> >>>> frames, unicast frames with the device bridge's MAC address, and
> >>>> multicast frames with ICMPv6 multicast address. All other frames
> >>>> are not
> >> passed
> >>>> to the host and are handled by the switch, forwarding each frame
> >>>> with its standard forwarding logic. The port can be shut off if it
> >>>> is blocked and those frames will not pass through that port. The
> >>>> host gets BPDU frames so that the bridge can determine each port's
> >>>> The other broadcast, unicast, and multicast frames passed to the
> >>>> host are necessary if some other network devices want to
> >>>> communicate with the host. As the forwarding is done by hardware
> >>>> rather than
> >> software,
> >>>> overall performance does increase.
> >>> What about LACP needed by bridging?
> >> I am not aware of LACP and do not know how this protocol works under
> >> bridging. If the requirement is certain multicast frames do not get
> >> forwarded and must pass to the host bridge, I can add those fixed
> >> multicast addresses. The static MAC table has 8 entries, so there
> >> 4 more to use.
> > Anything 01:80:C2:00:00:00 should go local host.
> > LACP is part of 802.3ad bonding and uses 01:80:C2:00:02
> > In general anything to 01:80:C2:00:00:XX is likely to be used by some
> IEEE 802 standard for link
> > only multicast.
I wouldn't worry about anything but STP.
> If the strict requirement is to support all 01:80:C2:00:00:XX multicast
> addresses, my scheme will not work. It was designed only for STP, as
> most our customers request that feature.
> I will pass your suggestions to our hardware engineers so that they can
> develop a better switch engine.
It is fine as is, just a warning of what standards committees are
likely to invent in future.
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