Unicast Flooding

Julio Arruda jarruda-gter at jarruda.com
Thu Jun 18 21:49:56 UTC 2009

Steven King wrote:
> Very true Eric. Microsoft even acknowledges the issue, and still has not
> fixed it. I have had a few customers use NLB and have this issue.
> Eric Gauthier wrote:
>> Brian,
>>> The first is preventing it in the first place.
>> As annoying as this might sound, this is one of the
>> standard operating modes for load balancing within 
>> a Microsoft server cluster (see NLB).  We've tried
>> to avoid it, but it seems to come up around once a 
>> year from someone on our campus...
>> Eric :)

I understand is 'working as designed' ?

Much like the Stonegate (?) Firewall redundancy trick ?
It was a little worse when doing the multicast-l2 to a unicast-l3 
address trick..

By the way, if you think this is funny in a campus ethernet backbone..
Try it in an old ATM/LANE environment..I had customer that had the 
chance to try it, and wanted a root cause analysis.
The BUS switch, was NOT happy in forwarding all the traffic going to the 
firewall cluster :-)...

More information about the NANOG mailing list