RE: [PATCH 2.6.33 1/3] net: Micrel KSZ8841/2 PCI Ethernet driver

From: Ha, Tristram
Date: Tue Jan 19 2010 - 19:36:32 EST

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.

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.
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