From: Erick B. (erickbe@xxxxxxxxx)
Date: Fri Jun 08 2001 - 01:52:50 GMT-3
Maybe someone made a connection between VLAN 10 and
the other VLANs thus making it one big VLAN. Are there
any other hubs or switches in the mix? This can be
hard to track down depending on # of devices.
You can also look at the cam table and see what port
the other PC is hanging off of to see if it's in the
correct VLAN its suppose to be in.
HTH, Erick
--- Troy Edington <TEdington@ingenuity.com> wrote:
> Hello group,
>
> I am having a problem with a catalyst 6509.
> Specifically the problem is
> that traffic seems to be leaking between two
> logically separated VLAN's. I
> run my Sniffer on a span port with one source port
> in VLAN 10 pointing to
> it(A Solaris box). I am spanning transmitting
> traffic only, just to verify
> that it is the switch transmitting and not feedback
> from the one machine.
> Here is specifically what I see.
>
> Vlans involved
> VLAN 10 10.80.10.0/24
> VLAN 30 10.80.30.0/24
>
> This machine has an IP of 10.80.10.20 (VLAN 10)
>
> I configured the Sniffer to ignore all packets with
> this IP in it. What I
> see was kind of amazing
>
> Immediately I see lots of traffic from other VLAN 10
> machines going to this
> port. This is not broadcast or multicast traffic
> but unicast traffic For
> example 10.80.10.30 to 10.80.10.40, etc etc shows up
> in the Sniffer (Both DS
> Pro and Snoop on Solaris)
>
> If that wasn't bad enough I see an occasional packet
> from a totally separate
> VLAN 30 10.80.30.18 10.80.30.22 Now this is local
> traffic what the hell is
> it doing in VLAN 10
>
> I understand from Cisco and please someone correct
> me if I am wrong. When a
> packet hits the back plane it is by default sent to
> every port and it is up
> to the CPU to instruct all ports except the correct
> destination port to drop
> the traffic. There can be leakage if your back
> plane and/or CPU is heavily
> utilized. Well I am at 4% CPU utilization and
> throughput utilization is
> low. (I am only using 48 Fast Ethernet ports on the
> 6509)
>
> I am running the following
> ver 6.1a
> I am only running Layer 2 on the switch no MSFC
> routing (The hardware is
> installed but we are not using it)
> I have tried sniffing other ports with the same
> result
> no trunking is going on anywhere
> no port-channeling anywhere
>
>
> Everything runs fine and the network is up but I
> would like to know what is
> going on. Any ideas anyone ?? I searched for bugs
> and solutions on the CCO
> with not much luck.
>
> Thanks in advance for any suggestions
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