Extra VLAN interface on Access-layer switches

[Patrick McHenry]

I've been going through some configs on some access switches. I've noticed that some of the switches, in addition to have a management vlan interface with an ip address, they have a vlan 5 interface with no ip address. Vlan 5 is alive and well on both of our core switches with ip addresses along with 50 other valns on each. I don't think that these access switches should have this extra vlan interface for no reason. Would any of you agree? And could this cause any problems? I've attached the output of the vlan 5 interface on the access switch:

[Jon Marshall]

Patrick

Couple of things -

1) on access-layer switches that are not doing inter-vlan routing you only need on L3 SVI up and running and that is used to manage the switch itself ie. nothing to do with user traffic.

2) if the switch is L2 capable only then you won't be able to have more than one L3 vlan interface up/up at the same time. So these switches must be 2960/3560/3750/4500/6500 ?

As the switches already have a working L3 vlan interface with an IP address then no, you don't get any benefit from having the vlan 5 interface on the switch.

Jon

[glen.grant]

  Some inexperienced people think you create a vlan by creating a layer 3 SVI  and then they get  left in the config doing nothing.

[Patrick McHenry]

Thanks for the responses. Is having the vlan 5 interface going to cause any problems though? O, just have no consequence at all?

Thanks, Pat

[cadet alain · Accepted solution]

Hi,

It has no ip address so it can't do anything.

Regards.

Alain.

[Patrick McHenry]

Thanks, Alain.