update for 2021 pdf version

.gitignore

@@ -7,3 +7,5 @@ pkt/*png
 python/*
 # tmp files during builds
 tmp/*
+# venv for python build
+venv/*

conf.py

@@ -80,7 +80,7 @@
 # The short X.Y version.
 version = '3'
 # The full version, including alpha/beta/rc tags.
-release = 'alpha'
+release = '2021'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -97,11 +97,11 @@
 
 # List of directories, relative to source directory, that shouldn't be searched
 # for source files.
-exclude_trees = ['_build']
+exclude_trees = ['_build', 'venv', 'python', 'tmp']
 
 # List of files that should not be automatically compiled by sphynx because they are included
 
-exclude_patterns = [ '*#*', "python/*" , "principles/dv.rst", "principles/linkstate.rst", '\._*rst']
+exclude_patterns = [ '*#*', "python/*" , "principles/dv.rst", "principles/linkstate.rst", '\._*rst', "venv/*", "tmp/*"]
 
 # epilog add to all included files
 #rst_epilog = """

exercises/routing-protocols.rst

@@ -1206,7 +1206,6 @@ d. What are the BGP messages that will be exchanged when the link between ``AS3`
 	\node[as, right=of AS4] (AS5) {AS5};
 	\node[as, right=of AS5] (AS7) {AS7};
 	\node[as, right=of AS6] (AS8) {AS8};
-	\node[as, right=of AS7] (AS8) {AS8};
 	\node[as, right=of AS8] (AS1) {AS1};
 	\node[as, right=of AS7] (AS9) {AS9};
 

glossary.rst

@@ -10,7 +10,7 @@ Glossary
 .. glossary::
    :sorted:
 
-   ascii
+   ASCII
 	The American Standard Code for Information Interchange (ASCII) is a character-encoding scheme that defines a binary representation for characters. The ASCII table contains both printable characters and control characters. ASCII characters were encoded in 7 bits and only contained the characters required to write text in English. Other character sets such as Unicode have been developed later to support all written languages.
 
    anycast
@@ -52,9 +52,6 @@ Glossary
    PBL
 	Problem-based learning is a teaching approach that relies on problems.
 
-   DNS
-        The Domain Name System is a distributed database that allows to map names on IP addresses.
-
    packet
 	a packet is the unit of information transfer in the network layer
 
@@ -190,16 +187,11 @@ Glossary
    SMTP
 	The Simple Mail Transfer Protocol is defined in :rfc:`821`
 
-   POP
-	The Post Office Protocol is defined in :rfc:`1939`
-
-   IMAP
-	The Internet Message Access Protocol is defined in :rfc:`3501`
 
    FTP
 	The File Transfer Protocol is defined in :rfc:`959`
 
-   SSH
+   ssh
 	The Secure Shell (SSH) Transport Layer Protocol is defined in :rfc:`4253`
 
    telnet
@@ -210,7 +202,7 @@ Glossary
 
 
    DNS
-	The Domain Name System is defined in :rfc:`1035`
+        The Domain Name System is a distributed database that allows to map names on IP addresses. It is defined in :rfc:`1035`
 
    RPC
 	Several types of remote procedure calls have been defined. The RPC mechanism defined in :rfc:`5531` is used by applications such as NFS
@@ -269,9 +261,7 @@ Glossary
    ARP
 	The Address Resolution Protocol is a protocol used by IPv4 devices to obtain the datalink layer address that corresponds to an IPv4 address on the local area network. ARP is defined in :rfc:`826`	
 
-   ISO
-	The International Standardization Organization
-
+	
    minicomputer
 	A minicomputer is a multi-user system that was typically used in the 1960s/1970s to serve departments. See the corresponding Wikipedia article for additional information : https://en.wikipedia.org/wiki/Minicomputer
 
@@ -290,7 +280,7 @@ Glossary
    ISO-3166
 	An :term:`ISO` standard that defines codes to represent countries and their subdivisions. See http://www.iso.org/iso/country_codes.htm    
 
-   vnc
+   VNC
 	A networked application that allows to remotely access a computer's Graphical User Interface. See https://en.wikipedia.org/wiki/Virtual_Network_Computing
 
    ISP

index.rst

@@ -18,10 +18,12 @@ Computer Networking : Principles, Protocols and Practice, third edition
 
     The development of this edition of the textbook is carried out on `https://github.com/CNP3/ebook <https://github.com/CNP3/ebook>`_ 
 
-    The source code of the entire textbook is written in `reStructuredText <http://docutils.sourceforge.net/rst.html>`_ and uses several `sphinx <http://sphinx.pocoo.org>`_ features. You can browse these sources from `github <https://github.com/CNP3/ebook/tree/master>`_
+    The source code of the entire textbook is written in `reStructuredText <http://docutils.sourceforge.net/rst.html>`_ and uses several `sphinx <http://sphinx.pocoo.org>`_ features. You can browse these sources from `github <https://github.com/CNP3/ebook/tree/master>`_ You can download a pdf version from :download:`tmp/latex/CNP3.pdf`
 
-    You can access a demo version of the e-book from `http://beta.computer-networking.info <http://beta.computer-networking.info>`_ 
+    The online version of the e-book at `http://beta.computer-networking.info <http://beta.computer-networking.info>`_ contains online exercises. 
 
+
+
 .. _toc:
 
 .. toctree:: 
@@ -104,7 +106,9 @@ Part 3: Practice
    exercises/routing-protocols
    exercises/lan
 
-..   exercises/ex-app
+
+.. old
+   ..   exercises/ex-app
 ..   exercises/netkit-app
 ..   exercises/netkit-tcp
 ..   exercises/packetdrill

principles/dv.rst

@@ -63,7 +63,7 @@ To understand the operation of a distance vector protocol, let us consider the n
 
 .. figure:: /principles/figures/dv-1.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Operation of distance vector routing in a simple network
 
@@ -80,7 +80,7 @@ At this point, all routers can reach all other routers in the network thanks to
 
 .. figure:: /principles/figures/dv-full.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Routing tables computed by distance vector in a simple network
 
@@ -104,7 +104,7 @@ At this point, all routers have a routing table allowing them to reach all other
 
 .. figure:: /principles/figures/dv-failure-2.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Routing tables computed by distance vector after a failure
 
@@ -160,7 +160,7 @@ Unfortunately, split-horizon, is not sufficient to avoid all count to infinity p
 
 .. figure:: /principles/figures/dv-infinity.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Count to infinity problem
 

principles/linkstate.rst

@@ -25,7 +25,7 @@ When a link-state router boots, it first needs to discover to which routers it i
 
 .. figure:: /principles/figures/ls-hello.png
    :align: center
-   :scale: 100   
+   :scale: 70   
 
    The exchange of HELLO messages
 
@@ -90,7 +90,7 @@ To ensure that all routers receive all LSPs, even when there are transmissions e
 
 .. figure:: /principles/figures/ls-lsdb.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Link state databases received by all routers 
 
@@ -106,7 +106,7 @@ When a link fails, the two routers attached to the link detect the failure by th
 
 .. figure:: /principles/figures/ls-twoway.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    The two-way connectivity check
 
@@ -119,7 +119,7 @@ To compute its forwarding table, each router computes the spanning tree rooted a
 
 .. figure:: /principles/figures/ls-computation.png
    :align: center
-   :scale: 100   
+   :scale: 120   
 
    Computation of the forwarding table
 

principles/referencemodels.rst

@@ -44,7 +44,7 @@ An important point to note about the Physical layer is the service that it provi
 
 .. figure:: /principles/figures/ref-model-phys.png
    :align: center
-   :scale: 80
+   :scale: 100
 
    The Physical layer
 
@@ -75,7 +75,7 @@ The `Datalink layer` allows directly connected hosts to exchange information, bu
 
 .. figure:: /principles/figures/ref-model-net.png
    :align: center
-   :scale: 80 
+   :scale: 100 
 
    The network layer
 
@@ -91,7 +91,7 @@ There are different types of transport layers. The most widely used transport la
 
 .. figure:: /principles/figures/ref-model-transport.png
    :align: center
-   :scale: 80 
+   :scale: 100 
 
    The transport layer
 
@@ -104,7 +104,7 @@ The upper layer of our architecture is the `Application layer`. This layer inclu
 
 .. figure:: /principles/figures/ref-model-app.png
    :align: center
-   :scale: 50 
+   :scale: 100 
 
    The Application layer
 
@@ -153,7 +153,7 @@ Compared to the five layers reference model explained above, the :term:`OSI` ref
 
 .. figure:: /principles/figures/ref-model-osi.png
    :align: center
-   :scale: 80 
+   :scale: 100 
 
    The seven layers of the OSI reference model
 

principles/reliability.rst

@@ -162,7 +162,7 @@ Many other types of encodings have been defined to transmit information over an
 
  .. figure:: figures/manchester.png
     :align: center
-    :scale: 70
+    :scale: 50
 
     Manchester encoding
 
@@ -173,7 +173,7 @@ Many other types of encodings have been defined to transmit information over an
 
 .. figure:: figures/physical-layer.png
    :align: center
-   :scale: 80
+   :scale: 100
 
    The Physical layer
 
@@ -559,7 +559,7 @@ The Alternating Bit Protocol uses a single bit to encode the sequence number. It
 
 .. figure:: figures/abp-sender-fsm.png 
    :align: center
-   :scale: 80 
+   :scale: 60 
 
    Alternating bit protocol : Sender FSM
 
@@ -571,7 +571,7 @@ The receiver first waits for `D(0,...)`. If the frame contains a correct `CRC`,
 
 .. figure:: figures/abp-receiver-fsm.png
    :align: center
-   :scale: 70 
+   :scale: 60 
 
    Alternating bit protocol : Receiver FSM
 
@@ -686,7 +686,7 @@ Go-back-n and selective repeat
 
 To overcome the performance limitations of the alternating bit protocol, reliable protocols rely on `pipelining`. This technique allows a sender to transmit several consecutive frames without being forced to wait for an acknowledgment after each frame. Each data frame contains a sequence number encoded in an `n` bits field.
 
-.. figure:: figures/pipelining.png
+.. figure:: figures/pipelining2.png
    :align: center
    :scale: 70 
 
@@ -696,9 +696,9 @@ To overcome the performance limitations of the alternating bit protocol, reliabl
 
 This is implemented by using a `sliding window`. The sliding window is the set of consecutive sequence numbers that the sender can use when transmitting frames without being forced to wait for an acknowledgment. The figure below shows a sliding window containing five segments (`6,7,8,9` and `10`). Two of these sequence numbers (`6` and `7`) have been used to send frames and only three sequence numbers (`8`, `9` and `10`) remain in the sliding window. The sliding window is said to be closed once all sequence numbers contained in the sliding window have been used. 
 
-.. figure:: figures/slidingwin.png
+.. figure:: figures/slidingwin2.png
    :align: center
-   :scale: 70 
+   :scale: 100 
 
    The sliding window 
 
@@ -707,7 +707,7 @@ The figure below illustrates the operation of the sliding window. It uses a slid
 
 .. figure:: figures/gbnwin.png
    :align: center
-   :scale: 70 
+   :scale: 60 
 
    Sliding window example 
 
@@ -717,7 +717,7 @@ In practice, as the frame header includes an `n` bits field to encode the sequen
 
 .. figure:: figures/gbnwinex.png
    :align: center
-   :scale: 70 
+   :scale: 60 
 
    Utilisation of the sliding window with modulo arithmetic
 
@@ -737,7 +737,7 @@ The simplest sliding window protocol uses the `go-back-n` recovery. Intuitively,
 The figure below shows the FSM of a simple `go-back-n` receiver. This receiver uses two variables : `lastack` and `next`. `next` is the next expected sequence number and `lastack` the sequence number of the last data frame that has been acknowledged. The receiver only accepts the frame that are received in sequence. `maxseq` is the number of different sequence numbers (:math:`2^n`).
 
 
-.. figure:: figures/gbn-rec.png
+.. figure:: figures/gbn-rec2.png
    :align: center
    :scale: 70 
 
@@ -747,16 +747,16 @@ The figure below shows the FSM of a simple `go-back-n` receiver. This receiver u
 A `go-back-n` sender is also very simple. It uses a sending buffer that can store an entire sliding window of frames [#fsizesliding]_ . The frames are sent with increasing sequence numbers (modulo `maxseq`). The sender must wait for an acknowledgment once its sending buffer is full. When a `go-back-n` sender receives an acknowledgment, it removes from the sending buffer all the acknowledged frames and uses a retransmission timer to detect frame losses. A simple `go-back-n` sender maintains one retransmission timer per connection. This timer is started when the first frame is sent. When the `go-back-n sender` receives an acknowledgment, it restarts the retransmission timer only if there are still unacknowledged frames in its sending buffer. When the retransmission timer expires, the `go-back-n` sender assumes that all the unacknowledged frames currently stored in its sending buffer have been lost. It thus retransmits all the unacknowledged frames in the buffer and restarts its retransmission timer.
 
 
-.. figure:: figures/gbn-sender.png
+.. figure:: figures/gbn-sender2.png
    :align: center
-   :scale: 70 
+   :scale: 60 
 
    Go-back-n : sender FSM
 
 
 The operation of `go-back-n` is illustrated in the figure below. In this figure, note that upon reception of the out-of-sequence frame `D(2,c)`, the receiver returns a cumulative acknowledgment `C(OK,0)` that acknowledges all the frames that have been received in sequence. The lost frame is retransmitted upon the expiration of the retransmission timer.
 
-.. figure:: figures/gbnex.png
+.. figure:: figures/gbnex2.png
    :align: center
    :scale: 70 
 
@@ -777,7 +777,7 @@ The main advantage of `go-back-n` is that it can be easily implemented, and it c
 
 A `selective repeat` receiver maintains a sliding window of `W` frames and stores in a buffer the out-of-sequence frames that it receives. The figure below shows a five-frame receive window on a receiver that has already received frames `7` and `9`.
 
-.. figure:: figures/selrepeatwin.png
+.. figure:: figures/selrepeatwin2.png
    :align: center
    :scale: 70 
 
@@ -862,7 +862,7 @@ In the figure above, when the sender receives `C(OK,0,[2])`, it knows that all f
 
 Reliable protocols often need to send data in both directions. To reduce the overhead caused by the acknowledgments, most reliable protocols use `piggybacking`. Thanks to this technique, a datalink entity can place the acknowledgments and the receive window that it advertises for the opposite direction of the data flow inside the header of the data frames that it sends. The main advantage of piggybacking is that it reduces the overhead as it is not necessary to send a complete frame to carry an acknowledgment. This is illustrated in the figure below where the acknowledgment number is underlined in the data frames. Piggybacking is only used when data flows in both directions. A receiver will generate a pure acknowledgment when it does not send data in the opposite direction as shown in the bottom of the figure.
 
-.. figure:: figures/piggyback.png 
+.. figure:: figures/piggyback2.png 
    :align: center
    :scale: 70