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Forum Replies

  1. Tunnel interface ip is not required.is it not necessary?

  2. If you need some help with this, it’s best to your topology and configs on the GNS3Vault forum. We can take a look there…

  3. The major differences:

    MCT - MTU is 1480, less overhead, supports only a single passenger protocol, mode is ipv6ip.

    GRE - MTU is 1476, more overhead, supports multiple passenger protocols, mode is gre.

  4. Hello Chris

    I belive what @zz.alnajjar is referring to is a Manually Configured Tunnel (MCT) although it does not have an official such name. What the manually configured tunnel is, is an IP packet inside an IP packet. A doubly encapsulated packet. If this is configured, the overhead will just be 20 bytes, which is the size of the header of a standard IPv4 packet, thus prodcing an MTU of 1500-20 = 1480. GRE on the other hand has a header of 24 bytes providing an MTU of 1500-24 = 1476.

    More info can be found on page 2 of this Cisco Documentation.

    I hope this has been helpful!


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