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IPv6 Networks

Basic questions on IPv6 Networks

Before starting to determine the paths that packets will follow in an IPv6 network, it is important to remember how to convert IPv6 addresses in binary numbers.

An IPv6 forwarding table contains a list of IPv6 prefixes with their associated nexthop or outgoing interface. When an IPv6 router receives a packet, it forwards it according to its forwarding table. Note that IPv6 routers forward packets along the *longest match* between the destination address of the packet and the routes in the forwarding table.

Now that you master the basics, you can determine the paths followed by IPv6 packets in simple networks.

Design questions

Consider the network shown in the figure below. In this network, the following addresses are used.

host ``A`` : ``2001:db8:1341:1::A`` and its default route points to ``2001:db8:1341:1::1``

host ``B`` : ``2001:db8:1341:4::B`` and its default route points to ``2001:db8:1341:4::4``

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, address ``2001:db8:1341:23::2`` on its South-West interface and address ``2001:db8:1341:24::2`` on its South interface.

router ``R3`` uses address ``2001:db8:1341:34::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

router ``R4`` uses address ``2001:db8:1341:34::4`` on its West interface, address ``2001:db8:1341:24::4`` on its North interface and address ``2001:db8:1341:4::4`` on its East interface

The forwarding paths used in a network depend on the forwarding tables installed in the network nodes. Sometimes, these forwarding tables must be configured manually.

In this network, propose the forwarding tables of ``R2`` and ``R3`` that ensure that hosts ``A`` and ``B`` can exchange packets in both directions.

Consider the same network as in the previous question, but now the forwarding tables of ``R2`` and ``R3`` are configured as shown below :

In this network, select `all` the rules in the shown forwarding tables that ensure that the packets sent from ``A`` to ``B`` follow the reverse path of the packets sent by ``B`` to ``A``.

router ``R2`` uses address ``2001:db8:1341:12::2`` on its West interface, and address ``2001:db8:1341:24::2`` on its South interface

router ``R3`` uses address ``2001:db8:1341:34::3`` on its East interface and address ``2001:db8:1341:13::3`` on its North interface