a 3750 can act as a layer3 switch by adding the “ip routing” command.
It can automatically route between locally created vlans because it considers them as connected interfaces (given that the SVIs are created).
on a device, there are 3 types of traffic: control, management, end user.
Control traffic such as CDP, DTP, PAgP goes through vlan1 between Cisco switches, even if you clear it from trunks.
By default, native vlan traffic is untagged. But there’s a Cisco command that tells the switch to tag all vlans.
by default, native vlan = vlan1. If we set the native vlan to vlan100, then vlan100 frames will be untagged on trunks, and vlan1 frames will be tagged.
SMI: Standard Multilayer Image
EMI: Enhanced Multilayer Image
if switch is acting L2, then we should set a Default Gateway on it to make the management vlan reachable remote ; if it is acting L3, it will have routes instead.
switch and Management vlan
the management IP address must be reachable from remote
best practice: use a same subnet to manage all network devices