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../../protocols/ipv6.rst:189
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There is one difficulty with the utilization of these IPv6 prefixes. Consider Belnet, the Belgian research ISP that has been allocated the ``2001:6a8::/32`` prefix. Universities are connected to Belnet. UCLouvain uses prefix ``2001:6a8:3080::/48`` while the University of Liege uses ``2001:6a8:2d80::/48``. A commercial ISP uses prefix ``2a02:2788::/32``. Both Belnet and the commercial ISP are connected to the global Internet.
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../../protocols/ethernet.rst:178
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1000Base-SX
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../../protocols/routing.rst:175
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The OSPF Designated Router election procedure is defined in :rfc:`2328`. Each router can be configured with a router priority that influences the election process since the router with the highest priority is preferred when an election is run.
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../../protocols/tcp.rst:200
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To avoid the `SYN flood` attacks, recent TCP implementations no longer enter the `SYN Rcvd` state upon reception of a `SYN segment`. Instead, they reply directly with a `SYN+ACK` segment and wait until the reception of a valid `ACK`. This implementation trick is only possible if the TCP implementation is able to verify that the received `ACK` segment acknowledges the `SYN+ACK` segment sent earlier without storing the initial sequence number of this `SYN+ACK` segment in a TCB. The solution to solve this problem, which is known as `SYN cookies <http://cr.yp.to/syncookies.html>`_ is to compute the 32 bits of the `ISN` as follows :
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../../protocols/tls.rst:299
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A TLS cipher suite is usually represented as an ASCII string that starts with TLS and contains the acronym of the key exchange algorithm, the encryption scheme with the key size and its mode of operation and the authentication algorithm. For example, ``TLS_DHE_RSA_WITH_AES_128_GCM_SHA256`` is a TLS cipher suite that uses the ``DHE_RSA`` key exchange algorithm with 128 bits AES in GCM mode for encryption and SHA-256 for authentication. The official list of TLS cipher suites is maintained by IANA [#fianaTLS]_. The NULL acronym indicates that no algorithm has been specified. For example, ``TLS_ECDH_RSA_WITH_NULL_SHA`` is a cipher suite that does not use any encryption but still uses the ``ECDH_RSA`` key exchange and ``SHA`` for authentication.
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../../protocols/wifi.rst:160
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In fact, the [IEEE802.11]_ frame format contains a fourth optional address field. This fourth address is only used when an 802.11 wireless network is used to interconnect bridges attached to two classical LAN networks.
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../../bibliography.rst:350
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Williams, R. `A painless guide to CRC error detection algorithms`, August 1993, unpublished manuscript, https://web.archive.org/web/20060101004751/http://www.ross.net/crc/download/crc_v3.txt
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../../glossary.rst:180
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hub
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../../principles/network.rst:257
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The last, but important, point to discuss about the `data plane` of the networks that rely on the datagram mode is their addressing scheme. In the examples above, we have used letters to represent the addresses of the hosts and network nodes. In practice, all addresses are encoded as a bit string. Most network technologies use a fixed size bit string to represent source and destination address. These addresses can be organized in two different ways.
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../../principles/reliability.rst:223
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01111110011011111011111011111011001001111110
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../../principles/transport.rst:201
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As the transport layer is built on top of the network layer, it is important to know the key features of the network layer service. In this book, we only consider the `connectionless network layer service` which is the most widespread. Its main characteristics are :
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../../principles/sharing.rst:241
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Based on the feedback received from the network, the hosts can adjust their transmission rate. We discuss in section `Congestion control` some techniques that allow hosts to react to congestion.
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../../principles/security.rst:634
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A drawback of this approach is that Bob is forced to perform two public key computations : one encryption to send the random nonce to Alice and one decryption to recover the nonce encrypted by Alice. If these computations are costly from a CPU viewpoint, this creates a risk of Denial of Service Attacks were attackers could try to access Bob's computer and force it to perform such costly computations. Bob is more at risk than Alice in this situation and he should not perform complex operations before being sure that he is talking with Alice. An alternative is shown in the time sequence diagram below.
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../../exercises/ipv6.rst:533
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The syntax of IPMininet_ is relatively simple and can be learned by looking at a few examples.
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../../exercises/routing-protocols.rst:841
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the eBGP session with ``fe80::c001:dcff:fe49:a512`` with an AS-Path of ``AS2`` (see last column)
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../../exercises/tcp-2.rst:738
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Assuming that there are no losses and that there is no congestion in the network. If the sender writes `x` bytes on a newly established TCP connection, derive a formula that computes the minimum time required to deliver all these `x` bytes to the receiver. For the derivation of this formula, assume that `x` is a multiple of the maximum segment size and that the receive window and the slow-start threshold are larger than `x`.
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../../protocols/bgp.rst:237
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When a BGP message is received, the router first applies the peer's `import filter` to verify whether the message is acceptable or not. If the message is not acceptable, the processing stops. The pseudo-code below shows a simple `import filter`. This `import filter` accepts all routes, except those that already contain the local AS in their AS-Path. If such a route was used, it would cause a routing loop. Another example of an `import filter` would be a filter used by an Internet Service Provider on a session with a customer to only accept routes towards the IP prefixes assigned to the customer by the provider. On real routers, `import filters` can be much more complex and some `import filters` modify the attributes of the received BGP `UPDATE` [WMS2004]_ .
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../../protocols/email.rst:232
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z
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../../protocols/ethernet.rst:255
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Operation of Ethernet switches
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../../protocols/http.rst:192
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In both HTTP requests and responses, the MIME document refers to a representation of the document with the MIME headers indicating the type of document and its size.
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