# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2019 Olivier Bonaventure
# This file is distributed under the same license as the Computer networking
# : Principles, Protocols and Practice package.
# FIRST AUTHOR <EMAIL@ADDRESS>, 2019.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Computer networking : Principles, Protocols and "
"Practice 3\n"
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"POT-Creation-Date: 2019-10-09 12:39+0000\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
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#: ../../exercises/network.rst:8
msgid ""
"This is an unpolished draft of the third edition of this e-book. If you "
"find any error or have suggestions to improve the text, please create an "
"issue via https://github.com/CNP3/ebook/issues?milestone=2 or help us by "
"providing pull requests to close the existing issues."
msgstr ""

#: ../../exercises/network.rst:12
msgid "Network : Open questions"
msgstr ""

#: ../../exercises/network.rst:14
msgid ""
"In your daily life, you also use hierarchical and flat address spaces. "
"Can you provide examples of these two types of addresses and discuss the "
"benefits of using a hierarchical or flat addressing space in this "
"particular context ?"
msgstr ""

#: ../../exercises/network.rst:16
msgid ""
"The network below uses port forwarding with flat addresses. The network "
"boots and all hosts start one after the other. Explain at each step how "
"the packets are forwarded and how the port forwarding tables of the "
"network nodes are modified. Host `C` sends a packet to host `B`. Some "
"time later, host `A` sends a packet to host `C`. Finally, host `B` sends "
"a packet to host `A`."
msgstr ""

#: ../../exercises/network.rst:42
msgid ""
"Same question as above, but the network is modified as shown in the "
"figure below."
msgstr ""

#: ../../exercises/network.rst:67
msgid ""
"Routing protocols used in data networks only use positive link weights. "
"What would happen with a distance vector routing protocol in the network "
"below that contains a negative link weight ?"
msgstr ""

#: ../../exercises/network.rst:86
msgid ""
"When a network specialist designs a network, one of the problems that he "
"needs to solve is to set the metrics the links in his network. In the "
"USA, the Abilene network interconnects most of the research labs and "
"universities. The figure below shows the topology  of this network in "
"2009."
msgstr ""

#: ../../exercises/network.rst:92
msgid "The Abilene network"
msgstr ""

#: ../../exercises/network.rst:94
msgid ""
"In this network, assume that all the link weights are set to 1. What is "
"the paths followed by a packet sent by the router located in `Los "
"Angeles` to reach :"
msgstr ""

#: ../../exercises/network.rst:96
msgid "the router located in `New York`"
msgstr ""

#: ../../exercises/network.rst:97
msgid "the router located in `Washington` ?"
msgstr ""

#: ../../exercises/network.rst:99
msgid ""
"Is it possible to configure the link metrics so that the packets sent by "
"the router located in `Los Angeles` to the routers located in "
"respectively `New York` and `Washington` do not follow the same path ?"
msgstr ""

#: ../../exercises/network.rst:101
msgid ""
"Is it possible to configure the link weights so that the packets sent by "
"the router located in `Los Angeles` to router located in `New York` "
"follow one path while the packets sent by the router located in `New "
"York` to the router located in  `Los Angeles` follow a completely "
"different path ?"
msgstr ""

#: ../../exercises/network.rst:103
msgid ""
"Assume that the routers located in `Denver` and `Kansas City` need to "
"exchange lots of packets. Can you configure the link metrics such that "
"the link between these two routers does not carry any packet sent by "
"another router in the network ?"
msgstr ""

#: ../../exercises/network.rst:105
msgid ""
"In the five nodes network shown below, can you configure the link metrics"
" so that the packets sent by router `E` to router `A` use link `B->A` "
"while the packets sent by router `B` use links `B->D` and `D->A`?"
msgstr ""

#: ../../exercises/network.rst:129
msgid ""
"In the five nodes network shown above, can you configure the link weights"
" so that the packets sent by router `E` (resp. `F`) follow the `E->B->A` "
"path (resp. `F->D->B->A`) ?"
msgstr ""

#: ../../exercises/network.rst:132 ../../exercises/network.rst:154
#: ../../exercises/network.rst:184 ../../exercises/network.rst:216
msgid "Consider the network shown in the figure below."
msgstr ""

#: ../../exercises/network.rst:152
msgid ""
"Assuming that the network uses source routing, what are the possible "
"paths from `R1` to `R4` ?"
msgstr ""

#: ../../exercises/network.rst:176
msgid ""
"The network operator uses would like to have the following paths in this "
"network :"
msgstr ""

#: ../../exercises/network.rst:178
msgid "`R3->R2->R4->R5` and `R1->R2->R5`"
msgstr ""

#: ../../exercises/network.rst:180
msgid ""
"Is it possible to achieve these paths and if so what are the required "
"forwarding tables ?"
msgstr ""

#: ../../exercises/network.rst:182 ../../exercises/network.rst:214
msgid "Same question with virtual circuits."
msgstr ""

#: ../../exercises/network.rst:208 ../../exercises/network.rst:238
msgid "The network operator would like to use the following paths :"
msgstr ""

#: ../../exercises/network.rst:210
msgid "`R1->R2->R4` and `R3->R2->R5->R4`"
msgstr ""

#: ../../exercises/network.rst:212 ../../exercises/network.rst:242
msgid ""
"Are these paths possible with link-state or distance vector routing ? If "
"yes, how do configure the link weights. If no, explain your answer."
msgstr ""

#: ../../exercises/network.rst:240
msgid "`R1->R5->R4` and `R3->R2->R4`"
msgstr ""

#: ../../exercises/network.rst:247
msgid "Network: Discussion questions"
msgstr ""

#: ../../exercises/network.rst:250
msgid ""
"The network below uses port forwarding tables. It has been running for "
"several hours and all hosts have exchanged packets. What is the content "
"of the port forwarding tables ?"
msgstr ""

#: ../../exercises/network.rst:273
msgid ""
"At this point, a new link is added between `R1` and `R3`. What happens "
"for the forwarding of packets ?"
msgstr ""

#: ../../exercises/network.rst:276
msgid ""
"The network below uses port forwarding tables. What happens if host `A` "
"moves by removing its link with `R1` and replacing it with a link with "
"`R3`? How should networks using port forwarding deal with such mobile "
"hosts ?"
msgstr ""

#: ../../exercises/network.rst:299
msgid ""
"Some hosts need to be multihomed, i.e. attached to two different network "
"nodes as shown in the figure below."
msgstr ""

#: ../../exercises/network.rst:323
msgid "Would this network work correctly with port-forwarding tables if :"
msgstr ""

#: ../../exercises/network.rst:325
msgid "Host `A` uses the same flat address for both links."
msgstr ""

#: ../../exercises/network.rst:326
msgid "Host `A` uses a different flat address on each of its links"
msgstr ""

#: ../../exercises/network.rst:328
msgid ""
"What are the advantages and drawbacks of flat addresses versus "
"hierarchical addresses ?"
msgstr ""

#: ../../exercises/network.rst:332
msgid ""
"Let us now consider the transient problems that mainly happen when the "
"network topology changes. For this, consider the network topology shown "
"in the figure below and assume that all routers use a distance vector "
"protocol that uses split horizon."
msgstr ""

#: ../../exercises/network.rst:356
msgid ""
"If you compute the routing tables of all routers in this network, you "
"would obtain a table such as the table below :"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Destination"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Routes on A"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Routes on B"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Routes on C"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Routes on D"
msgstr ""

#: ../../exercises/network.rst:360
msgid "Routes on E"
msgstr ""

#: ../../exercises/network.rst:363
msgid "A"
msgstr ""

#: ../../exercises/network.rst:363 ../../exercises/network.rst:364
#: ../../exercises/network.rst:365 ../../exercises/network.rst:366
#: ../../exercises/network.rst:367
msgid "0"
msgstr ""

#: ../../exercises/network.rst:363
msgid "1 via A"
msgstr ""

#: ../../exercises/network.rst:363 ../../exercises/network.rst:365
msgid "2 via B"
msgstr ""

#: ../../exercises/network.rst:363 ../../exercises/network.rst:367
msgid "3 via C"
msgstr ""

#: ../../exercises/network.rst:363
msgid "4 via D"
msgstr ""

#: ../../exercises/network.rst:364
msgid "B"
msgstr ""

#: ../../exercises/network.rst:364
msgid "1 via B"
msgstr ""

#: ../../exercises/network.rst:364 ../../exercises/network.rst:366
msgid "2 via C"
msgstr ""

#: ../../exercises/network.rst:364
msgid "3 via D"
msgstr ""

#: ../../exercises/network.rst:365
msgid "C"
msgstr ""

#: ../../exercises/network.rst:365
msgid "1 via C"
msgstr ""

#: ../../exercises/network.rst:365 ../../exercises/network.rst:367
msgid "2 via D"
msgstr ""

#: ../../exercises/network.rst:366
msgid "D"
msgstr ""

#: ../../exercises/network.rst:366
msgid "3 via B"
msgstr ""

#: ../../exercises/network.rst:366
msgid "1 via D"
msgstr ""

#: ../../exercises/network.rst:367
msgid "E"
msgstr ""

#: ../../exercises/network.rst:367
msgid "4 via B"
msgstr ""

#: ../../exercises/network.rst:367
msgid "1 via E"
msgstr ""

#: ../../exercises/network.rst:370
msgid ""
"Distance vector protocols can operate in two different modes : `periodic "
"updates` and `triggered updates`. `Periodic updates` is the default mode "
"for a distance vector protocol. For example, each router could advertise "
"its distance vector every thirty seconds. With the `triggered updates` a "
"router sends its distance vector when its routing table changes (and "
"periodically when there are no changes)."
msgstr ""

#: ../../exercises/network.rst:372
msgid ""
"Consider a distance vector protocol using split horizon and `periodic "
"updates`. Assume that the link `B-C` fails. `B` and `C` update their "
"local routing table but they will only advertise it at the end of their "
"period. Select one ordering for the  `periodic updates` and every time a "
"router sends its distance vector, indicate the vector sent to each "
"neighbor and update the table above. How many periods are required to "
"allow the network to converge to a stable state ?"
msgstr ""

#: ../../exercises/network.rst:374
msgid ""
"Consider the same distance vector protocol, but now with `triggered "
"updates`. When link `B-C` fails, assume that `B` updates its routing "
"table immediately and sends its distance vector to `A` and `D`. Assume "
"that both `A` and `D` process the received distance vector and that `A` "
"sends its own distance vector, ... Indicate all the distance vectors that"
" are exchanged and update the table above each time a distance vector is "
"sent by a router (and received by other routers) until all routers have "
"learned a new route to each destination. How many distance vector "
"messages must be exchanged until the network converges to a stable state "
"?"
msgstr ""

#: ../../exercises/network.rst:376
msgid ""
"Consider again the network shown above. After some time, link state "
"routing converges and all routers compute the same routing tables as "
"above."
msgstr ""

#: ../../exercises/network.rst:378
msgid ""
"An important difference between OSPF and RIP is that OSPF routers flood "
"link state packets that allow the other routers to recompute their own "
"routing tables while RIP routers exchange distance vectors. Consider that"
" link `B-C` fails and that router `B` is the first to detect the failure."
" At this point, `B` cannot reach anymore `C`, `D` and `E`. `C` cannot "
"reach `B` and `A` anymore."
msgstr ""

#: ../../exercises/network.rst:380
msgid ""
"Router `B` will flood its updated link state packet through the entire "
"network and all routers will recompute their forwarding table. Upon "
"reception of a link state packet, routers usually first flood the "
"received link-state packet and then recompute their forwarding table. "
"Assume that `B` is the first to recompute its forwarding table, followed "
"by `D`, `A`, `C` and finally `E`."
msgstr ""

#: ../../exercises/network.rst:382
msgid ""
"After each update of a forwarding table, verify which pairs of routers "
"are able to exchange packets. Provide your answer using a table similar "
"to the one shown above."
msgstr ""

