It looks like you have an SVI configured on VLAN 100. An SVI is a virtual interface and does not correspond to any physical interface. The name of the SVI interfaces are always the VLANs on which they belong. So you must have an interface called VLan100 on the switch, and that is the port to which the 10.0.1.0/25 network is attached.
Take a look at these lessons to learn more about how VLANs and Layer 3 switches operate:
Thanks for the explanations @lagapidis . By the way, how l3 switch knows dip is in different subnet? Is it like host do AND operation between DIP and subnetmask? So that dest network address can be looked into route table for egress port.
My statement was a bit confusing, and not quite accurate . Let me try to clarify.
A switch will not be able to determine if that IP address is in the same subnet or not, because there are no subnet masks conveyed within an IP header. If it is in a different subnet, the sending host will have determined that and populated the destination MAC address accordingly. If the destination is in a different subnet, the destination MAC address would be that of the SVI that is acting as the default gateway.
So the determining of whether or not the destination IP is in the same subnet is not done by the switch, but has already been done by the host, and the appropriate destination MAC is then used based on that. Does that make sense?
. Let me try to clarify.