[c-nsp] Re-thinking (remembering) how a switch operates

[John Edwards]

Greg Schwimer wrote:
> I've seen this scenario from time to time - hosts in the same VLAN on
> different switches see a stream of traffic destined for a host on a
> different switch.  I've seen it occur for a number of reasons, but
> generally have been able to blame this behaviour on Windows Load
> Balancing Services (WLBS).

Cisco HSRP will cause the same scenario if you have multiple routers 
each on a different switch (as you do when you're trying to eliminate 
single points of failure). The problem is likely to occur where there 
are asynchronous paths through an ethernet network and destination hosts 
that have no reason to broadcast or return traffic (like syslog servers 
or netflow collectors).

John Edwards