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Why VPWS service – MPLS has a two ethernet frame headers?

Last updated on December 27, 2018

        I am trying to understand VPWS services, and going through <a href="https://tools.ietf.org/html/rfc4448" rel="nofollow noreferrer"><em>RFC 4448, Encapsulation Methods for Transport of Ethernet over MPLS Networks</em></a>.
Here is the packet capture: enter image description here
  1. Why there is a need for again source MAC and destination MAC addresses?

  2. My understanding is that it uses MPLS labeling for switching/routing within the core network. Once it moves out from the PE, it will go to its attachment circuit based on the ethernet frame- destination MAC address. Is that correct?

  3. I see that in the packet capture, there are two Ethernet frame headers - The red one shows the ethernet source and destination MAC addresses of its immediate neighbor. Is the label not being used for switching?

  4. If so, then why two labels?

  5. I am confused about the second ethernet frame - My understanding is that it is for the attachment circuit - like where to go after reaching the far end PE.

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