[nsp] 3550 not learning MAC addresses?

Yuval Ben-Ari yuvalba at netvision.net.il
Sat Feb 7 06:08:37 EST 2004

is this switch acting as the L3 for those hosts ?
what if you try to ping the hosts from the switch do you see the MAC
learned then ?
does the hosts send traffic via this switch or via some alternative path
we had similar problem where hosts would use different path for outgoing
traffic then the path traffic was coming, as a result the switch which
was not in the outgoing path did not learn the MAC addresses and flooded
the traffic.
the solution was to make sure traffic is coming and going out via same

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net 
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of John Osmon
> Sent: Thursday, February 05, 2004 20:47
> To: cisco-nsp at puck.nether.net
> Subject: [nsp] 3550 not learning MAC addresses?
> I've got a 3550-24-EMI running 12.1.8EA1c that isn't learning MAC
> addresses, and thus flooding unicast packets to ports it shouldn't.
> Static MAC assignments work fine, and manage to stem the 
> floods, but it
> isn't an ideal situation.  (Call me picky, but I like my bridges to
> *learn* which stations are where...)
> The VLAN in question only has 6 stations, with most of the traffic
> passing between two routers at roughly 40Mbps.  One station is
> a Cisco 2511, and its 10Mbps ethernet port gets overrun without
> the static MAC assignments.
> I don't expect many changes on this segment, so static MACs are
> an OK workaround, but I really want to find out *why* this is
> occurring.  I see no obvious misconfigurations, and googling hasn't
> turned up much of use.  Anyone here have any ideas?
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