Analyzing Packets for VLAN info

Answered Question
Feb 1st, 2010

Hello Experts,

I'm looking for some help & would like to preface my post by stating that I have limited experience with routing / switching  and am thankful for any assistance.

We have configured spanning of various vlans to an interface on a server used to record and store phone calls for agents in our contact center. Now that we're getting the desired traffic, I'd like to perform some clean up and remove the unneccessary vlans from the monitor sessions on the switch (6509). I figured I could just capture the packets (on the server int) and use the traces to identify the pertinent vlan ids from the recorded calls. The problem is when I analyze these packets I see no vlan information. Is my approach off here? I know we are tagging data. Any extra steps I should be taking? Let me know if there's any more info I could provide.

Thanks again,
Kelly

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Correct Answer by Jon Marshall about 6 years 10 months ago

Googi1974 wrote:

Hello Experts,

I'm looking for some help & would like to preface my post by stating that I have limited experience with routing / switching  and am thankful for any assistance.

We have configured spanning of various vlans to an interface on a server used to record and store phone calls for agents in our contact center. Now that we're getting the desired traffic, I'd like to perform some clean up and remove the unneccessary vlans from the monitor sessions on the switch (6509). I figured I could just capture the packets (on the server int) and use the traces to identify the pertinent vlan ids from the recorded calls. The problem is when I analyze these packets I see no vlan information. Is my approach off here? I know we are tagging data. Any extra steps I should be taking? Let me know if there's any more info I could provide.

Thanks again,
Kelly

Kelly

Is the server NIC 802.1q capable and is the switchport that connects to the server configured as a trunk port or an access port ?

If you want to preserve the tags then you will need to configure the connection as a trunk port otherwise the switch will strip the vlan tags from the packets before sending to the server.

Jon

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Correct Answer
Jon Marshall Mon, 02/01/2010 - 08:18

Googi1974 wrote:

Hello Experts,

I'm looking for some help & would like to preface my post by stating that I have limited experience with routing / switching  and am thankful for any assistance.

We have configured spanning of various vlans to an interface on a server used to record and store phone calls for agents in our contact center. Now that we're getting the desired traffic, I'd like to perform some clean up and remove the unneccessary vlans from the monitor sessions on the switch (6509). I figured I could just capture the packets (on the server int) and use the traces to identify the pertinent vlan ids from the recorded calls. The problem is when I analyze these packets I see no vlan information. Is my approach off here? I know we are tagging data. Any extra steps I should be taking? Let me know if there's any more info I could provide.

Thanks again,
Kelly

Kelly

Is the server NIC 802.1q capable and is the switchport that connects to the server configured as a trunk port or an access port ?

If you want to preserve the tags then you will need to configure the connection as a trunk port otherwise the switch will strip the vlan tags from the packets before sending to the server.

Jon

Googi1974 Mon, 02/01/2010 - 09:00

Thank you for your guidance, Jon.

- The technical specifications for the NIC does list 802.1q under the Compliance section.

- I just checked and the port on the switch is not "trunked."

Can you see any reason to advise not to configure this port as a trunk temporarily?

-Kelly

Jon Marshall Mon, 02/01/2010 - 09:03

Googi1974 wrote:

Thank you for your guidance, Jon.

- The technical specifications for the NIC does list 802.1q under the Compliance section.

- I just checked and the port on the switch is not "trunked."

Can you see any reason to advise not to configure this port as a trunk temporarily?

-Kelly

Kelly

If you want to capture the vlan tags then you will have to configure it as a trunk. It should be fine. Make sure you configure the NIC for 802.1q as well - you may need to consult vendor docs for that.

Jon

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