L2TPv3 vs GRE for layer 2 bridging?

Discussion in 'Cisco' started by Rob, Feb 27, 2004.

  1. Rob

    Rob Guest

    I need to create a solution which allows me to bridge non-IP traffic
    between two sites, but I'd like to do it over the Internet instead of
    getting a leased line. With a P-to-P T1, this is easy. Turn on
    bridging of the appropriate interfaces and away you go.

    But over an IP network, what is the best way? Does basic GRE
    tunneling work, or does it require L2TPv3, of which I read a little
    about on CCO.

    Assume the ISP will not be helping with this endeavor. I want to do
    it via the endpoint routers which I control.

    Rob, Feb 27, 2004
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  2. Hi,

    Haven't done L2TPv3 but GRE works fine. The approach is actually the same as
    with the PtP T1, just bridge between the appropriate interfaces (ex. int
    Ethernet0/0 and int Tunnel0).

    Erik Tamminga, Feb 28, 2004
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  3. Rob

    Rob Guest

    I haven't been able to put Bridge-group X on a Tunnel interface.
    Rob, Feb 28, 2004
  4. I tried bridging over a GRE tunnel once; I had a terrible time of it. You
    should probably look into using DLSw+ for this. This is what its designed
    for, and you can encrypt it via IPSEC. This is probably the best way to do
    it. I've never done L2TPv3 VPNs before; they may work better.

    Craig Johnson, CCIE #6965
    Craig Johnson, Feb 29, 2004
  5. Rob

    Rob Guest

    I didn't think of DLSW. It routes any layer 2 packet, not just
    Rob, Feb 29, 2004
  6. DLSw+ will pass all of your ethernet frames. What makes it so powerful for
    applications like this is that you can restrict communication between MAC
    addresses, which will lower the bandwidth you use. You can also
    troubleshoot issues much more effectively with DLSw+. Now, the only thing
    you need to worry about is performance. Layer 2 tends to be a little delay
    sensitive, and you might have issues going over the internet. This applies
    to whatever technology you decide to use, though.

    Craig Johnson, CCIE #6965
    Craig Johnson, Feb 29, 2004
  7. Rob

    Rob Guest

    I asksed the TAC. They said DLSW will not work, but L2TPv3 is what I
    want. Reading up on it.......
    Rob, Mar 1, 2004
  8. L2TPv3 is a great technology, and probably will be what you want. However,
    it's really new and requires 12.3T, which I'm not prepared to run yet.
    They are wrong about DLSw+, though. It will bridge anything in ethernet.
    You have to use a BVI and not put an IP on the ethernet interface, but it
    will work. I'm not sure why they would have told you that it doesn't. They
    may not support this configuration, though. If you've got the means, use
    L2TPv3. It's definitely the way to go.

    Craig Johnson, CCIE #6965
    Craig Johnson, Mar 1, 2004
  9. Rob


    Nov 2, 2011
    Likes Received:
    On what line cards running L2TPv3 and GRE on 7600 platform? Necessary forwarding through the transit network MPLS L2 channel.

    Thanks in advance!
    NixLorien, Nov 2, 2011
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