2. cnp3-ebook
3. exercises/routing-policies
4. English
5. Browse

1 / 2

/ 2

Read-only strings

• Untranslated strings • state:empty
• Unfinished strings • state:<translated
• Translated strings • state:>=translated
• Strings marked for edit • state:needs-editing
• Strings with suggestions • has:suggestion
• Strings with variants • has:variant
• Strings with labels • has:label
• Strings with context • has:context
• Unfinished strings without suggestions • state:<translated AND NOT has:suggestion
• Strings with comments • has:comment
• Strings with any failing checks • has:check
• Approved strings • state:approved
• Strings waiting for review • state:translated

Target string

• Position and priority
• Position
• Priority
• Labels
• Source string
• Target string
• String age
• Number of words
• Number of comments
• Number of failing checks
• Key

	English
	An ICMPv6 error message includes in its message body the beginning of the IPv6 packet that triggered this error. How many bytes of the original packet must be returned to allow the host to recover the original source and destination addresses and source and destination ports of the packet that caused the error ?
	Are all ASes capable of reaching all the other ASes in this simple Internet ?
	A simple network
	A ``traceroute6`` towards ``ipv6.google.com`` provides the following output :
	Can you explain why at the eighth, ninth and tenth hopes several IPv6 addresses are reported in the ``traceroute6`` output ?
	``Code==0``
	Consider that the AS stub (`AS456`) shown in the figure below decides to advertise two ``/48`` prefixes instead of its allocated ``/47`` prefix.
	Consider the interdomain topology shown in the figure below.
	Consider the interdomain topology shown in the figure below. Assuming, that `AS1` advertises prefix ``2001:db8:1::/48``, `AS2` prefix ``2001:db8:2::/48``, ... compute the routing tables of the different ASes.
	Consider the network below in which a stub domain, `AS456`, is connected to two providers `AS123` and `AS789`. `AS456` advertises its prefix to both its providers. On the other hand, `AS123` advertises ``2001:db8:dead::/48`` while `AS789` advertises ``2001:db8:beef::/48`` and ``2001:db8:dead:cafe::/63``. Via which provider will the packets destined to ``2001:db8:dead:cafe::1`` will be received by `AS456` ?
	Consider the network shown below. In this network, the metric of each link is set to `1` except link `A-B` whose metric is set to `4` in both directions. In this network, there are two paths with the same cost between `D` and `C`. Old routers would randomly select one of these equal cost paths and install it in their forwarding table. Recent routers are able to use up to `N` equal cost paths towards the same destination.
	Exercises
	from `AS1` to `AS4`
	from `AS4` to `AS1`
	from `AS4` to `AS2`
	How is the reachability of these addresses affected when link `R1`-`R3` fails ?
	Inter-domain routing
	In this internet, some ASes cannot reach all other ASes. Can you fix the problem by adding one shared-cost peering link or one customer-provider peering link ?
	In this network, what are the paths :
	On recent routers, a lookup in the forwarding table for a destination address returns a set of outgoing interfaces. How would you design an algorithm that selects the outgoing interface used for each packet, knowing that to avoid reordering, all segments of a given TCP connection should follow the same path ?