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../../protocols/tcp.rst:219
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The first parameter which is negotiated during the establishment of a TCP connection is the Maximum Segment Size (:term:`MSS`). The MSS is the size of the largest segment that a TCP entity is able to process. According to :rfc:`879`, all TCP implementations must be able to receive TCP segments containing 536 bytes of payload. However, most TCP implementations are able to process larger segments. Such TCP implementations use the TCP MSS Option in the `SYN`/`SYN+ACK` segment to indicate the largest segment they are able to process. The MSS value indicates the maximum size of the payload of the TCP segments. The client (resp. server) stores in its :term:`TCB` the MSS value announced by the server (resp. the client).
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../../protocols/tls.rst:338
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a `Length` field. A TLS record cannot be longer than 16,384 bytes.
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../../glossary.rst:243
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The Internet Corporation for Assigned Names and Numbers (ICANN) coordinates the allocation of domain names, IP addresses and AS numbers as well protocol parameters. It also coordinates the operation and the evolution of the DNS root name servers.
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../../principles/reliability.rst:239
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`0` : `0110000` b
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../../principles/transport.rst:222
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When two applications need to communicate, they need to structure their exchange of information. Structuring this exchange of information requires solving two different problems. The first problem is how to represent the information being exchanged knowing that the two applications may be running on hosts that use different operating systems, different processors and have different conventions to store information. This requires a common syntax to transfer the information between the two applications. For this chapter, let us assume that this syntax exists and that the two applications simply need to exchange bytes. We will discuss later how more complex data can be encoded as sequences of bytes to be exchanged. The second problem is how to organize the interactions between the application and the underlying network. From the application's viewpoint, the `network` will appear as the `transport layer` service. This `transport layer` can provide three types of services to the applications :
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../../principles/sharing.rst:269
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`Deterministic` or `pessimistic` MAC algorithms. These algorithms assume that collisions are a very severe problem and that they must be completely avoided. These algorithms ensure that at any time, at most one device is allowed to send a frame on the LAN. This is usually achieved by using a distributed protocol which elects one device that is allowed to transmit at each time. A deterministic MAC algorithm ensures that no collision will happen, but there is some overhead in regulating the transmission of all the devices attached to the LAN.
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../../principles/security.rst:775
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Now consider that Mallory wants to be authenticated as Alice. The above protocol has a subtle flaw that could be exploited by Mallory. This flaw can be exploited if Alice and Bob can act as both client and server. Knowing this, Mallory could operate as follows. Mallory starts an authentication with Bob faking himself as Alice. He sends a first message to Bob including Alice's identity.
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../../exercises/ipv6.rst:612
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``2001:db8:1341:12::/64`` on the link between ``r1`` and ``r2``
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../../exercises/routing-protocols.rst:898
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We first connect to the BGP daemon on router `as2`. In addition to the `show` commands that have been described earlier, the router also supports privileged commands that can change its configuration. Before executing these commands, we must enter the privileged mode with the `enable` command. On production routers, this command requires a password to verify the credentials of the network administrator. The `#` prompt indicates that we are allowed to execute privileged commands. We first check the state of the BGP sessions with the `show bgp summary` commands. There are two BGP sessions configured on this router.
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../../exercises/tcp-2.rst:876
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On Linux, most of the parameters to tune the TCP stack are accessible via :manpage:`sysctl`. These parameters are briefly described in https://github.com/torvalds/linux/blob/master/Documentation/networking/ip-sysctl.txt and in the :manpage:`tcp` manpage. Each script sets some of these configuration variables.
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../../protocols/bgp.rst:279
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Let us assume that the `R1-R2` BGP session is the first to be established. A `BGP Update` message sent on such a session contains three fields :
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../../protocols/email.rst:234
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../../protocols/ethernet.rst:303
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When all switches boot, their `MAC address table` is empty. Assume that host `A` sends a frame towards host `C`. Upon reception of this frame, switch1 updates its `MAC address table` to remember that address `A` is reachable via its West port. As there is no entry for address `C` in switch1's `MAC address table`, the frame is forwarded to both switch2 and switch3. When switch2 receives the frame, its updates its `MAC address table` for address `A` and forwards the frame to host `C` as well as to switch3. switch3 has thus received two copies of the same frame. As switch3 does not know how to reach the destination address, it forwards the frame received from switch1 to switch2 and the frame received from switch2 to switch1... The single frame sent by host `A` will be continuously duplicated by the switches until their `MAC address table` contains an entry for address `C`. Quickly, all the available link bandwidth will be used to forward all the copies of this frame. As Ethernet does not contain any `TTL` or `HopLimit`, this loop will never stop.
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../../protocols/http.rst:308
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The `Connection:` header is used with the `Keep-Alive` argument by the client to indicate that it expects the underlying TCP connection to be persistent. When this header is used with the `Close` argument, it indicates that the entity that sent it will close the underlying TCP connection at the end of the HTTP response.
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../../protocols/ipv6.rst:219
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a packet with destination ``2001:6a8:3880:40::2`` matches two routes : ``2001:6a8::/32`` and ``::/0``. The packet is forwarded via ``fe80::aaaa:bbbb``
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../../protocols/ethernet.rst:197
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The official list of all assigned Ethernet type values is available from http://standards.ieee.org/regauth/ethertype/eth.txt
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../../protocols/tcp.rst:221
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Another utilization of TCP options during connection establishment is to enable TCP extensions. For example, consider :rfc:`1323` (which is discussed in :ref:`TCPReliable`). :rfc:`1323` defines TCP extensions to support timestamps and larger windows. If the client supports :rfc:`1323`, it adds a :rfc:`1323` option to its `SYN` segment. If the server understands this :rfc:`1323` option and wishes to use it, it replies with a :rfc:`1323` option in the `SYN+ACK` segment and the extension defined in :rfc:`1323` is used throughout the TCP connection. Otherwise, if the server's `SYN+ACK` does not contain the :rfc:`1323` option, the client is not allowed to use this extension and the corresponding TCP header options throughout the TCP connection. TCP's option mechanism is flexible and it allows the extension of TCP while maintaining compatibility with older implementations.
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../../protocols/tls.rst:339
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a `TLSPlainText` that contains the encrypted data
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../../glossary.rst:42
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IETF
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../../principles/reliability.rst:240
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`z` : `1111010` b
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