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New Member

Cascade Configuration: Basic Question

Standard Config: [Switch]---802.1q---[Phone]---[PC]

Separate VLAN for voice and data.

What will happen if, for whatever reason, the IP phone failed. Can the PC bypass the phone automatically? If it does, how does the PC know which VLAN it should go to.

New Member

Re: Cascade Configuration: Basic Question

If your IP phone failed, you can plug in the network connection directly to the PC.

IP Phones exchange CDP information with their directly attached switch to negotiate the "auxillary vlan" (along with other parameters) that is configured in you catalyst switch.

Cisco Employee

Re: Cascade Configuration: Basic Question

If by "failed" you mean that the phone has power but is not registered to CallManager or can't get an IP address, then yes the PC will still work. And the VLAN that the PC will operate on is the VLAN that is configured on the switch port that the phone is connected to. The auxiliaryvlan (or voice vlan) is only used by the signaling and voice packets from the phone to the rest of the network, and this VLAN ID is learned by the phone via CDP from the switch.

However, if the phone does not have power, then obviously this will not work.

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