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Two-way (bi-directional) tunnels and overlay networks

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• Notable fact
  • The tunnel setup:

    created by the virtual interface:

    Network ID | Interface (port) -------------+------------------- 7.7.7.0 | 4.4.4.1

    is a

    uni-directional tunnel From router 2.2.2.1 To router 4.4.4.1

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  • Graphically:

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• Two-way (bi-directional) IP-in-IP tunneling
  • Fact:

    A bi-directional tunnel (= 2 way) is created using: Two uni-directional tunnels

  • How to set up a two-way tunnel:

    We first setup a one-way tunnel: Then setup another one-way tunnel backwards: Then the 2 one-way tunnels will make up a bi-directional tunnel: