Chapter 25 - Implementing IPv6 Routing

Question 1

What are some of the reasons that a IPv6 route would be added to a routing table?

Answer 1

• Connected and Local routes would be added via the configuration of IPv6 addresses on interfaces
• Static routes being configured
• Dynamically added via a routing protocol

Question 2

True or false. Routers don’t create Connected or Local routes for Link-Local addresses.

Answer 2

True.

Question 3

What prefix do IPv6 local routes have?

Answer 3

/128

Question 4

True or False. A static route to a link local address would function with the address on its own.

Answer 4

False. This also requires the outgoing interface to the link-local address since the router does not know where the link-local address is.

Question 5

What is the equivalent to 0.0.0.0/0 in IPv6?

Answer 5

::/0 - Used to configure default routes

Question 6

True or False. Default administrative distance values are the same for IPv4 routes as they are for IPv6. List the distances.

Answer 6

True.
- Connected - 0
- Static - 1
- NDP - 2
- EIGRP - 90
- OSPF - 110
- RIP - 120
- Unknown - 255

Question 7

What should always be checked when an IPv6 route has been statically configured incorrectly?

Answer 7

• Correct prefix length
• If the next hop is a link local address, is the link local address on the neighboring router and can you get to it via the configured outgoing interface
• Is the address correct
• Outgoing interface is on the local router not the neighboring router

Question 8

What checks will IOS complete on routes that have correct syntax to decide whether they can appear in the routing table?

Answer 8

• If the route uses an outgoing interface, the interface must be up/up
• If the router uses a next hop global unicast or unique local address for the next hop, the address must be reachable via another route
• If a route already exists for the same prefix, the static route must have a lower administrative distance

Question 9

What are the different types of static routes?

Answer 9

• Directly Attached - Only the exit interface is specified in the routing information. (In IPv6 these can’t be used if the exit interface is an Ethernet interface. Serial interfaces would work).
• Recursive - Only the next hop address is specified in the routing information. Recursive means that the router has to check its routing table multiple times. Once to find the address it is attempting to reach, and then a second time to find out how to reach the next hop address.
• Fully Specified - Both the exit interface and next hop address are specified in the routing information.