2. cnp3-ebook
3. English
4. Zen

62 ../../principles/sharing.rst:386
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Static allocation methods 25/10000 · 25
62 ../../principles/security.rst:714
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 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. 512/10000 · 512
62 ../../exercises/ipv6.rst:607
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Although IPMininet_ can assign prefixes and addresses automatically, we use manually assigned addresses in this example. 120/10000 · 120
62 ../../exercises/routing-protocols.rst:856
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 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. 754/10000 · 754
62 ../../exercises/tcp-2.rst:834
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Same question, but assume now that the fourth segment delivered by the sender experienced congestion (but was not discarded). 125/10000 · 125
62 ../../protocols/bgp.rst:265
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 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. 208/10000 · 208
62 ../../protocols/email.rst:234
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — S 1/10000 · 1
62 ../../protocols/ethernet.rst:289
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — From a security perspective, Ethernet hubs have the same drawbacks as the older coaxial cable. A host attached to a hub will be able to capture all the frames exchanged between any pair of hosts attached to the same hub. Ethernet switches are much better from this perspective thanks to the selective forwarding, a host will usually only receive the frames destined to itself as well as the multicast, broadcast and unknown frames. However, this does not imply that switches are completely secure. There are, unfortunately, attacks against Ethernet switches. From a security perspective, the `MAC address table` is one of the fragile elements of an Ethernet switch. This table has a fixed size. Some low-end switches can store a few tens or a few hundreds of addresses while higher-end switches can store tens of thousands of addresses or more. From a security point of view, a limited resource can be the target of Denial of Service attacks. Unfortunately, such attacks are also possible on Ethernet switches. A malicious host could overflow the `MAC address table` of the switch by generating thousands of frames with random source addresses. Once the `MAC address table` is full, the switch needs to broadcast all the frames that it receives. At this point, an attacker will receive unicast frames that are not destined to its address. The ARP attack discussed in the previous chapter could also occur with Ethernet switches [Vyncke2007]_. Recent switches implement several types of defenses against these attacks, but they need to be carefully configured by the network administrator. See [Vyncke2007]_ for a detailed discussion on security issues with Ethernet switches. 1675/10000 · 1675
62 ../../protocols/http.rst:252
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — However, as the web evolved to support richer documents containing images, opening a TCP connection for each URI became a performance problem [Mogul1995]_. Indeed, besides its HTML part, a web page may include dozens of images or more. Forcing the client to open a TCP connection for each component of a web page has two important drawbacks. First, the client and the server must exchange packets to open and close a TCP connection as we will see later. This increases the network overhead and the total delay of completely retrieving all the components of a web page. Second, a large number of established TCP connections may be a performance bottleneck on servers. 666/10000 · 666
62 ../../protocols/ipv6.rst:216
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — a packet with destination ``2a02:2788:2c4:16f::1`` received by router `R` is destined to a host on interface ``eth0`` . 119/10000 · 119
62 ../../protocols/ethernet.rst:180
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Optical fiber (experiences are performed with copper) 53/10000 · 53
62 ../../protocols/tcp.rst:210
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — As IP provides an unreliable connectionless service, the `SYN` and `SYN+ACK` segments sent to open a TCP connection could be lost. Current TCP implementations start a retransmission timer when they send the first `SYN` segment. This timer is often set to three seconds for the first retransmission and then doubles after each retransmission :rfc:`2988`. TCP implementations also enforce a maximum number of retransmissions for the initial `SYN` segment. 453/10000 · 453
62 ../../protocols/tls.rst:331
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — a `Type` that indicates the type of record. The most frequent type is `application data` which corresponds to a record containing encrypted data. The other types are `handshake`, `change_cipher_spec` and `alert`. 212/10000 · 212
62 ../../bibliography.rst:83
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Gao, L., Griffin, T., Rexford, J., `Inherently safe backup routing with BGP <https://dx.doi.org/10.1109/INFCOM.2001.916777>`_, Proceedings IEEE INFOCOM, April 2001 163/10000 · 163
62 ../../principles/transport.rst:242
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — These imperfections of the `connectionless network layer service` are caused by the operations of the `network layer`. This `layer` is able to deliver packets to their intended destination, but it cannot guarantee their delivery. The main cause of packet losses and errors are the buffers used on the network nodes. If the buffers of one of these nodes becomes full, all arriving packets must be discarded. This situation frequently happens in practice [#fqueuesize]_. Transmission errors can also affect packet transmissions on links where reliable transmission techniques are not enabled or because of errors in the buffers of the network nodes. 647/10000 · 647
63 ../../exercises/network.rst:376
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — E 1/10000 · 1
63 ../../bibliography.rst:84
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — Gettys, J., Nichols, K., `Bufferbloat: dark buffers in the internet <http://queue.acm.org/detail.cfm?id=2063196>`_. Communications of the ACM 55, no. 1 (2012): 57-65. 166/10000 · 166
63 ../../glossary.rst:231
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — 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. 246/10000 · 246
63 ../../principles/network.rst:383
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — In the above figure, assume that the network uses 16 bits addresses and that the prefix `01001010` has been assigned to the entire network. Since the network contains four routers, the network operator could assign one block of sixty-four addresses to each router. `R1` would use address `0100101000000000` while `A` could use address `0100101000000001`. `R2` could be assigned all addresses from `0100101001000000` to `0100101001111111`. `R4` could then use `0100101011000000` and assign `0100101011000001` to `B`. Other allocation schemes are possible. For example, `R3` could be allocated a larger block of addresses than `R2` and `R4` could use a sub-block from `R3` 's address block. 689/10000 · 689
63 ../../principles/reliability.rst:241
	English ↹ ↵ NBS … “ ” ‘ ’ ﹙-﹚ ‐ – — `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. 438/10000 · 438