VLAN / VLAN Interface confusion

Kyndall Taylor · ‎03-31-2017

I have (15) WS-C3650-48PD switches daisy-chained together with the SFP ports and fiber. I have added an additional VLAN (#2) to each switch.

24 ports are assigned to vlan 1 with device IP ranges from 192.168.0.x - 192.168.3.x 255.255.252.0

24 ports are assigned to vlan 2 with device IP ranges from 192.167.0.x - 192.167.3.x 255.255.252.0

I have a computer (IP of 192.168.0.1) plugged into SWITCH #1 into one of the VLAN 1 ports.

I need to manage each switch with telnet (I know, not secure). I have created a new IP address on EACH switch for each VLAN 1, so I have used 15 IP addresses just to manage the switches. Is this correct? It works, I can telnet or http to each switch, but I am confused as to where I need this many addresses for all the switches. I have seen documentation that says a VLAN only needs one IP address.

Maybe I am confusing a management VLAN with a VLAN or VLAN interface.

I just need to manage the switches with telnet / http at this point. Is the multiple address for telnet/ or http the way to go, or can I jump through switch 1 to the others somehow without the need for individual addresses on each switch?

Thanks for your time..

chrihussey · ‎03-31-2017

Yes, you are correct in that each switch would need its own management IP.

A VLAN does only need one IP address (although it could have secondary IPs). The key is that this statement applies to the VLAN interface that acts as the default gateway/routed layer 3 interface for the network.

Assuming each of the 15 access switches are strictly layer 2 devices, the VLAN 1 interface on each only define the switch as a host on that network / VLAN. Just like any other host they need to have a default gateway defined if you wish to access them from a different subnet.

Finally, it is not uncommon to define a VLAN just for switch management. If you did something like this, you'd have to define that VLAN as the native VLAN on the trunk ports between the access switches.

Hope this helps

Kyndall Taylor · ‎03-31-2017

Thanks for the additional information.