Inter-VLAN loop

[Dorwin Caballero]

How can I avoid loop between two different VLANs. I have already activated RPVST+ on all the switches.

[ccannon88567]

What makes you think that you have a L2 loop?

RPVST+ and PVST+ should prevent this? It may be that you have some incorrect additional fine tuning STP statements such as port fast applied incorrectly?

[Dorwin Caballero]

Hi, the problem is like this, one port is switchport access vlan 10 was accidentally connected to a patch panel connected to switchport accesds vlan 20. The network went down and the error loopback was detected. We have around 20 VLANs on our core/L3 switch.

[Skjalg Eggen]

Port security on access ports should do the trick.

The problem still exists, however, if you have trunk ports configured for your IP-Phones and some user decides to plug the PC end of the phone back into the other patch in the wall. This is bad. And I have yet to find a good solution to this problem.

Inter-VLAN loops on trunk ports. Possibly storm-control could be of some help?