[f-nsp] Odd MRP problem

[George B.]

Ok, wanted to follow up with the cause of this.   Vendor had used a single
mode fiber cable between two SR 10G optics in a metro circuit we lease.



On Mon, Sep 27, 2010 at 2:04 AM, Mike Hughes <mike at smashing.net> wrote:

> --On 27 September 2010 01:26:31 -0700 "George B." <georgeb at gmail.com>
> wrote:
>
>  Yes, there is a LAG in the ring.  There are two 1G ports aggregated
>> between two routers at one site.
>>
>
> Okay, so what this could be is either:
>
> a) Failure of source-port suppression for the LAG - so usually, when a
> frame arrives to a broadcast, multicast, or unknown unicast address, it is
> forwarded out of all ports in that vlan other than the one it arrived on.
> This behaviour is obviously modified for a LAG, so that other ports in the
> same LAG as the incoming port do not get a copy of the frame.
>
> However, I have seen this behaviour fail on some Brocade equipment (Mostly
> Jetcore/MG8, I think once on RX), which causes the flooded frames to
> "trombone" along the LAG. This would create lots of extra copies of the
> RHPs.
>
> It's likely to break control protocols using broadcast/multicast DAs, and
> cause a lot of what looks like station movement, so look for high CPU, and
> MAC addresses flipping between source ports.
>
> b) The other option is a bad FID being programmed for the destination MAC
> address for the MRP RHP, which is causing the RHPs to be forwarded out of
> the wrong port on one of the switches.
>
> Just some ideas to investigate.
>
> Mike
>
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