Author(s) Olivier Bonaventure
Deadline No deadline
Submission limit No limitation
Category tags IPv6


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IPv6 packet forwarding

Question 1: Paths in an IPv6 network

The forwarding tables used in an IPv6 network define the forwarding paths that are used for the packets. Consider the simple network depicted in the figure below. In this network, the hosts have the following addresses :

  • host A : 2001:db8:1341:1::A and its default route points to 2001:db8:1341:1::1
  • host B : 2001:db8:1341:3::B and its default route points to 2001:db8:1341:3::3

The routers have one address inside each network :

  • router R1 uses address 2001:db8:1341:1::1 on its West interface, address 2001:db8:1341:12::1 on its East interface and address 2001:db8:1341:13::1 on its South interface
  • router R2 uses address 2001:db8:1341:12::2 on its West interface and address 2001:db8:1341:23::2 on its South-West interface
  • router R3 uses address 2001:db8:1341:3::3 on its East interface, address 2001:db8:1341:23::3 on its North-East interface and address 2001:db8:1341:13::3 on its North interface

The forwarding tables of these three routers, ignoring the routes to the local interfaces, are shown in the figure below.

What is the path followed by the packets sent by A towards B ? Write your path as a A-Rw-Rx-Ry-Rz-B

Question 2: Path from B to A

What is the path followed by the packets sent by B towards A ? Write your path as a B-Rw-Rx-Ry-Rz-A