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  1. Hi Georgi,
    These terms all start to run together don’t they?

    First, let’s talk about AToM vs EoMPLS. EoMPLS is AToM that is transporting a specific protocol (Ethernet). AToM is capable of transporting other layer 2 protocols as well, so it has a more broad meaning. The confusion is that most people use Ethernet at layer 2, so in that case EoMPLS and AToM appears to be the same thing. Think of it this way: EoMPLS is a specific kind of AToM just like a Poodle is a specific kind of Dog.

    Now let’s talk about L2TPv3 vs EoMPLS. These are both trying to accomplish the same thing: Extend a layer 2 boundary across a WAN, but they use different protocols to do it. Each has their own pro’s and con’s. Here are a few highlights:

    Wide hardware support
    Better traffic engineering control

    Requires end-to-end MPLS configuration, which is usually more expensive to the customer

    Any IP based Internet connection is supported (DSL, Cable Modem, etc)
    Less expensive than MPLS

    Newer technology, so not as widely supported as EoMPLS

  2. Davis,
    With a network backbone that doesn’t support jumbo frames (meaning frames larger than 1500), you might have some trouble. Common practice is to set the entire core to support an MTU of 9216. You would have to support 14 bytes for Ethernet, 4 bytes for a VLAN tag (if you are using 802.1Q), 4 bytes for MPLS. So, far, that is 22 bytes of overhead, which would reduce your payload size to 1478. Whether you can force your MTU down so your core won’t exceed 1500 bytes, I just don’t know.

    I did find an article that might be of help, though:

    In the article, it states that the MTU on the physical ports must be set to at least 1504, and that the x-connect protocol actually checks to see whether the other end of the circuit has the same MTU.

  3. Hi Rene,

    Need your awesome lesson regarding VPLS/HVPLS/MPLS-TE very soon .The topic need to learn badly & you know your write up is simply excellent as compared to any other , Challenge !!! .So ,eagerly waiting for your excellent lesson.Thx


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