Hi dave,
1) can I shutdown the vlan 1 in a flat network, and at the same time able to manage the switch remotely? Otherwise, how do I enable remote management?
You can shutdown interface Vlan1 but you cannot deactivate or delete the VLAN1 itself. These are two different things. A switch behaves like an end host (a normal computer) attached to any VLAN for which it has an interface Vlan. This VLAN is called the management VLAN because in that VLAN, the switch has its IP address and gateway. Shutting down interface Vlan1 disconnects the switch from VLAN1, stopping VLAN1 from being a management VLAN. However, VLAN1 itself, as a virtual broadcast domain, still exists and carries frames through the switch. VLAN1 cannot be deleted, but it can be pruned off trunks if necessary, and generally, you can simply avoid using it for any purpose, and that will do.
If you deactivate interface Vlan1 and want to use a different management VLAN, simply create another VLAN that you want to become the management VLAN, and then create an interface Vlan for that new management VLAN, assign it an IP address, set up the default gateway using ip default-gateway command, set up trunks and/or access ports for that VLAN and you're done.
2) will there be any downtime to the user if I shutdown vlan1 at the L2 switch?
Shutting down interface Vlan1 will not impact any users.
1) At the router end is it necessary to shutdown vlan 1 and enable other vlan for flat network?
No, on routers, VLAN1 has no special meaning. You simply do not create a subinterface for VLAN1.
Best regards,
Peter
