I have a 3750 L3 and a 3550 which is connected (trunk) to the 3750.
All the VLANs are configured on the 3750.
When I ping a PC connected to the 3550 from insde the 3550, I get replies all good but the mac address which is returned is not the PC one.
I researched a bit and the mac address that the 3550 returns for the PC actually belongs to a VLAN configured at the 3750. This VLAN is not even the VLAN that the PC belongs to.
Is this the expected behavior?
One other point might be helpful. Remember that there are 2 places on the 3550 where you look and find MAC addresses. The layer 2 forwarding table (mac-address-table or cam depending on which switch platform) associates the MAC address of a device with the port it is connected to - and that is not what you are seeing. When you do show arp on a layer 2 switch you see IP addresses and MAC addresses that have been accessed from the management interface of the switch. The MAC that you see in the arp table is the MAC through which you send IP and it would be the MAC of the VLAN 2 interface on the 3750.
Yes, this is eactly what Rick and myself were describing. If the 3550 has an interface in vlan 2 which is up/up then to all intents and purposes this is the management vlan.
For the 3550 to ping a PC in vlan 13 it has to send it to the it's default-gateway which will be the vlan 2 interface on the 3750.