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../../exercises/tcp-2.rst:832
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Redraw the same figure assuming that the second segment that was delivered by the sender in the figure experienced congestion. In a network that uses Explicit Congestion Notification, this segment would be marked by routers and the receiver would return the congestion mark in the corresponding acknowledgment.
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../../protocols/bgp.rst:263
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If the import filter accepts the BGP message, the pseudo-code distinguishes two cases. If this is an `Update message` for prefix `p`, this can be a new route for this prefix or a modification of the route's attributes. The router first retrieves from its `RIB` the best route towards prefix `p`. Then, the new route is inserted in the `RIB` and the `BGP decision process` is run to find whether the best route towards destination `p` changes. A BGP message only needs to be sent to the router's peers if the best route has changed. For each peer, the router applies the `export filter` to verify whether the route can be advertised. If yes, the filtered BGP message is sent. Otherwise, a `Withdraw message` is sent. When the router receives a `Withdraw message`, it also verifies whether the removal of the route from its `RIB` caused its best route towards this prefix to change. It should be noted that, depending on the content of the `RIB` and the `export filters`, a BGP router may need to send a `Withdraw message` to a peer after having received an `Update message` from another peer and conversely.
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../../protocols/email.rst:234
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../../protocols/ethernet.rst:287
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Security issues with Ethernet hubs and switches
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../../protocols/http.rst:216
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HTTP was initially designed to share text documents. For this reason, and to ease the implementation of clients and servers, the designers of HTTP chose to open a TCP connection for each HTTP request. This implies that a client must open one TCP connection for each URI that it wants to retrieve from a server as illustrated on the figure below, showing HTTP 1.0 and the underlying TCP connection. For a web page containing only text documents this was a reasonable design choice as the client usually remains idle while the (human) user is reading the retrieved document.
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../../protocols/ipv6.rst:214
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With the longest match rule, the route ``::/0`` plays a particular role. As this route has a prefix length of `0` bits, it matches all destination addresses. This route is often called the `default` route.
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../../protocols/ethernet.rst:180
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40-100 Gbps
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../../protocols/tcp.rst:None
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Retransmitting the first `SYN` segment
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../../protocols/tls.rst:329
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A TLS record is always composed of four different fields :
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../../bibliography.rst:359
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Zheng, X., `Phishing with Unicode Domains <https://www.xudongz.com/blog/2017/idn-phishing/>`_, April 14, 2017, https://www.xudongz.com/blog/2017/idn-phishing/
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../../glossary.rst:168
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iBGP
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../../principles/reliability.rst:231
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`Bit stuffing` increases the number of bits required to transmit each frame. The worst case for bit stuffing is of course a long sequence of bits set to `1` inside the frame. If transmission errors occur, stuffed bits or markers can be in error. In these cases, the frame affected by the error and possibly the next frame will not be correctly decoded by the receiver, but it will be able to resynchronize itself at the next valid marker.
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../../principles/transport.rst:206
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the `connectionless network layer service` may delay, reorder or even duplicate SDUs
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../../principles/sharing.rst:260
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Medium Access Control algorithms
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../../principles/security.rst:714
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There are situations where symmetric authentication is required. In this case, each user must perform some computation with his/her private key. A possible exchange is the following. Alice sends her certificate to Bob. Bob replies with a nonce, :math:`R1`, and provides his certificate. Alice encrypts :math:`R1` with her private key and generates a nonce, :math:`R2`. Bob verifies Alice's computation and encrypts :math:`R2` with his private key. Alice verifies the computation and both have been authenticated.
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../../exercises/ipv6.rst:607
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Although IPMininet_ can assign prefixes and addresses automatically, we use manually assigned addresses in this example.
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../../exercises/routing-protocols.rst:856
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The BGP session starts with a TCP three-way handshake. Once the session has been established, both BGP daemons send an ``OPEN`` message describing their capabilities and the BGP extensions that it supports. The details of these extensions go beyond the scope of this book. However, it is important to note that the ``OPEN`` message contains the ``AS`` number of the router that sends the message and its identifier as a 32 bits IPv4 address. This router identifier uniquely identifies the router. The last mandatory parameter of the ``OPEN`` message is the `Hold Time`, i.e. the maximum delay between two successive messages over this BGP session. A BGP router should send ``KEEPALIVE`` messages every one third of the `Hold Time` to keep the session up.
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../../exercises/tcp-2.rst:834
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Same question, but assume now that the fourth segment delivered by the sender experienced congestion (but was not discarded).
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../../protocols/bgp.rst:265
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Let us now discuss in more detail the operation of BGP in an IPv6 network. For this, let us consider the simple network composed of three routers located in three different ASes and shown in the figure below.
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../../protocols/email.rst:234
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S
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