I wondering about best practices when it comes to addressing. For a new network I thought I would start it right by creating a loopback address and having that the address configured in TACACS and SolarWinds and that being the address we use to SSH to. For the layer 2 switches I'm not sure what to do.
I thought I would also create a Management VLAN on the Core switch and have all other layer 2, Management interfaces in that Subnet/VLAN. But, if there are no interfaces that are up in that VLAN, the VLAN is down and won't be reached. For instance; at one site we will have a stack of switches that will not require any trunks or interfaces that will need to carry the Management VLAN for this to work. Because there are no intrefaces up in the Management VLAN, the VLAN interface shows down.
Is there a practical solution for this?
And is there a way to configure the Management VLAN to always be up even if nothing is on it?
I had another thought - maybe it would be better to have loopback interfaces for routers and also core switches and then create a Management VLAN for layer 2 switches connecting to the core switch?
For your layer-2 devices only, you just need to create a management vlan and an svi and add it to the trunk link. That will bring up the interface even when there is noting connected to it.
so, on layer-2 devices
int vlan 20
ip address 10.10.10.1 255.255.255.0
desc mgmt vlan interface
Then add the vlan to your uplink
For your layer-3 device, it is good idea to use loopback interface.
Also, the newer switches (3750x, 3560x, 3850 series) all have an out of band management interface. You can use that to connect all your layer-2/3 switches to another switche, and than connect that switch to your router and have that subnet be routerd.
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