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Port monitor of an interface with both voice and data VLAN

I want to set up a monitor session on an interface that is connected to a IP phone (not a Cisco one). I am just curious to understand how it works with the monitor session with regard to the VLAN tagged traffic on that port. So the phone will have a data VLAN and a voice VLAN and traffic on each VLAN will be tagged with a different VLAN identifier. So on my destination monitor session port will I see all traffic from both VLANs? I am not too worried about seeing the VLAN tags themselves and I don't care which VLAN specific packets are from - I really just want to make sure that I see everything.

I am aware of the "encapsulation replicate" keyword on the monitor session which maintains the tagging when sent to the monitor destination and the issues around different OS (I am using Wireshark on Windows) stripping of 802.1q headers.

2 REPLIES

Hi, I believe if you run

Hi,

 

I believe if you run monitor session to the interface then it will let you monitor the traffic passes through that interface irrespective of vlans. In the monitor session if you point it to the vlan then it will monitor the traffic passes through the specific vlan

example syntax:

monitor session 1 source [interface [Fa|Gi][module]/[port]|vlan [vlan number]]
monitor session 1 destination interface [Fa|Gi]

Regards

Karthik

Hey,Yes with monitor session

Hey,

Yes with monitor session configured you will see everything going out and coming in to interface, however SPAN also does not normally monitor bridge protocol data unit (BPDU) packets and Layer 2 protocols, such as Cisco Discovery Protocol (CDP), VLAN Trunk Protocol (VTP), Dynamic Trunking Protocol (DTP), Spanning Tree Protocol (STP), and Port Aggregation Protocol (PAgP).

Check following for more information:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swspan.html#wp1204187

HTH.

Regards,

RS.

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