Transparent switch configuration on cisco 2960-x

joanny.fuvel.external · ‎11-30-2016

Hello,

I am facing an issue configuring a cisco 2960-x switch (ios 15.2)

I have only 2 interfaces (gi1/0/1 and gi1/0/2) in a vlan.
gi1/0/1 is connected to an host which emits several packet with different MAC-address,
including "fake" packets with mac-address 03ff.ffff.0000
gi1/0/2 is connected to another switch (which configuration can't be modified)

When I monitor the gi1/0/1 I can see all the packets including the "fake" packets
However, when I monitor the gi1/0/2 I can only see all the packets excluding the "fake" ones.

I would like the switch 2960-x to behave totally transparent and to transmit all packet with no treatment,
including the "fake" ones.

I already tried to enable "static mac-address" on gi1/0/2, also "multicast" and even "trunk mode",
but the "fake" packets are always invisible on this interface.

Is there something I'm missing?

Thank you.

Michal Bruncko · ‎12-01-2016

just to be sure, your "fake" MAC addresses are used as destination MACs, right? switch will not forward any frame sourced with multicast MAC address.

is the IGMP snooping on C2960-x disabled? your MAC address is both locally administered and multicast-type.

secondly I would start with testing and in first stage to send only frames with dst MAC addr configured as "locally administered" to see if they are passing to gi1/0/2.

if so, then switch to use multicast-type of dst MAC address frames and keeping local administered flag disabled.

only in case both tests before are passed I would focus to MAC with enabled both flags.

etienne.noblet.external · ‎12-01-2016

Hi, I am a collegue of Joanny.

The IGMP snooping on C2960-x is enable by default. And your are right it don't forward any frame sourced with multicast MAC address.

All frames with non multicast mac address pass to gi1/0/2.

After your response we are looking about MVR, but it use ip address. Our frames uses only mac address.

Then we saw that to use mac routing multicast we have to use a layer 3 switch.

The C2960-X is a layer 2 switch, only the c2960-XR is layer 3. We have a c4948 in spare witch is layer 3.

We test on it and it works good, all multicast frames pass trough gi1/2.

Thank you for your help.