Re: Peering VLANs and MAC addresses

[Niels Bakker <niels=nanog () bakker net>]

* randy () psg com (Randy Bush) [Thu 10 Nov 2005, 03:35 CET]:
> [ the voice of experience speaks ]
[..]
> thanks!  this approaches reassuring.  why does it tolerate 100 
> macs?  at first blush, i would think three or four would be a 
> bad enough sign.

I've seen several cases where a router goes bonkers and spews a bunch of 
broken frames - more than four but usually less than a hundred.  The 
frames get dropped but the port doesn't get shut down.  I have a hunch 
that it's connected with bad memory in the router, a pointer going awry 
somewhere, using some payload to fill an Ethernet frame header. 
Usually it goes away by itself without further outaged conditions.

So this could be a reason to set the limit at 100 instead of 4... 
another could be that the default in Foundry MG8 firmware is 128.

Also, AMS-IX implemented port security almost three years ago (we've 
presented about it at AMS-IX Technical Meetings, RIPE meetings and 
Euro-IX Forums).


        -- Niels.

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