topic RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address in ExtremeSwitching (EOS)

VoIP phone causing Loop - Disable port with Duplicate MAC Address

Bill_Handler — Tue, 23 Aug 2016 00:27:00 GMT

Customer has VoIP Phones. Users will plug both ports into wall jacks causing a loop. Looking for solution

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Roger_Green — Tue, 23 Aug 2016 00:30:00 GMT

only plug one jack in

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Balaji — Tue, 23 Aug 2016 00:30:00 GMT

Configure STP on the edge ports with BPDUSafeguard enabled.

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Roger_Green — Tue, 23 Aug 2016 00:31:00 GMT

computer goes into phone, phone goes into wall

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Paul_Russo — Tue, 23 Aug 2016 00:31:00 GMT

Hello Bill

Can you please tell me what switch you are using? If it is one that runs XOS as the operating system then you can use a feature called ELRP. It works similar to STP but it is not as configuration detailed. It is essentially two commands.

If it is EOS based or if there is a mixture then STP is a better fit.

Let us know
Thanks
P

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Bill_Handler — Tue, 23 Aug 2016 00:36:00 GMT

I tried to edit the original, but it wouldn't allow it...

The customer has Enterasys B5s with 6.71-6.81 code

More information - BPDUs are not passed through the phone. The VoIP VLAN is untagged as is the Data VLAN.

The data ports shows the same MAC address as the phone port.

Does anyone know of a way via CLI or Policy Manager to disable a port when it detects a duplicate MAC address in the filtering database on an edge port?

Normally we would use STP with edgeguard, but since the BPDUs are not passing across the phone, it doesn't help.

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Roger_Green — Tue, 23 Aug 2016 00:37:00 GMT

easy thing to do is setup voice vlan and let the phone tag the voice traffic

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Bill_Handler — Tue, 23 Aug 2016 00:40:00 GMT

Roger,

That won't stop the loop. The customer wants the VoIP to be on a different VLAN, but untagged to the phone.

RE: VoIP phone causing Loop - Disable port with Duplicate MAC Address

Erik_Auerswald — Tue, 23 Aug 2016 12:19:00 GMT

Hi Bill,

you cannot generally prevent all layer 2 loops in the presence of buggy or malicious gear, like the VoIP phones filtering BPDUs. Every loop detection protocol can be filtered out.

You should consider mitigating the effect of loops by using rate limiting for broadcast, multicast, and unknown unicast traffic. The B5 (and other EOS switches) have two mechanisms for this:

set port broadcast affects broadcasts only
set cos port-resource flood-ctrl 0.0 {unicast|multicast|broadcast} rate PPS set cos state enable

Erik