Exit Zen
29
../../protocols/http2.rst:224
English
The HTTP/2.0 streams can provide performance benefits, but they also increase the complexity of the implementations since an HTTP/2.0 receiver must be able to simultaneously process frames that correspond to different web objects. This complexity mainly resides on the client side. The HTTP/2.0 protocol includes several techniques that enable clients to manage the utilization of the HTTP/2.0 session.
0/4020 · 402
29
../../protocols/ipv6.rst:115
English
``fe80:0:0:0:219:e3ff:fed7:1204``
0/330 · 33
29
../../protocols/ethernet.rst:92
English
What is the Ethernet service ?
0/300 · 30
29
../../protocols/routing.rst:94
English
Let us first consider OSPF routing inside `area 2`. All routers in the area learn a route towards `2001:db8:1234::/48` and `2001:db8:5678::/48`. The two area border routers, `RB` and `RC`, create network summary advertisements. Assuming that all links have a unit link metric, these would be:
0/2920 · 292
29
../../protocols/rpc.rst:113
English
Upon reception of this JSON structure, the callee parses the object, locates the corresponding method and passes the parameters. This method returns a response which is also encoded as a JSON structure. This response contains the following fields:
0/2470 · 247
29
../../protocols/ssh.rst:225
English
``padding length`` : this is the number of random bytes that have been added at the end of the message.
0/1030 · 103
29
../../protocols/tcp.rst:57
English
the `TCP Header Length` (THL) or `Data Offset` field is a four bits field that indicates the size of the TCP header in 32 bit words. The maximum size of the TCP header is thus 64 bytes.
0/1850 · 185
29
../../protocols/tls.rst:98
English
Securely negotiate the cryptographic algorithms that will be used by the client and the server over the TLS session
0/1150 · 115
29
../../protocols/wifi.rst:26
English
74 Mbps
0/100 · 7
30
../../bibliography.rst:97
English
Jung, J., Sit, E., Balakrishnan, H., and Morris, R. 2002. `DNS performance and the effectiveness of caching <https://dx.doi.org/10.1109/TNET.2002.803905>`_. IEEE/ACM Transactions Networking 10, 5 (Oct. 2002), 589-603.
0/2170 · 217
30
../../glossary.rst:54 • ../../glossary.rst:211 • ../../glossary.rst:232
English
DNS
0/100 · 3
30
../../exercises/ex-sharing.rst:591
English
Consider the simple network depicted in the figure below.
0/570 · 57
30
../../principles/network.rst:116
English
A second type of problem may exist in networks using the datagram organization. Consider a path that contains a cycle. For example, router `R1` sends all packets towards destination `D` via router `R2`. Router `R2` forwards these packets to router `R3` and finally router `R3`'s forwarding table uses router `R1` as its nexthop to reach destination `D`. In this case, if a packet destined to `D` is received by router `R1`, it will loop on the `R1 -> R2 -> R3 -> R1` cycle and will never reach its final destination. As in the black hole case, the destination is not reachable from all sources in the network. In practice the loop problem is more annoying than the black hole problem because when a packet is caught in a forwarding loop, it unnecessarily consumes bandwidth. In the black hole case, the problematic packet is quickly discarded. We will see later that network layer protocols include techniques to minimize the impact of such forwarding loops.
0/9580 · 958
30
../../principles/transport.rst:65
English
`@` : `1000000b`
0/160 · 16
30
../../principles/security.rst:363
English
In the 1970s, Diffie and Hellman proposed in their seminal paper [DH1976]_, a different type of encryption : `public key cryptography`. In public key cryptography, each user has two different keys :
0/1980 · 198
30
../../exercises/dns.rst:84
English
Besides `dig`, another way to analyze the DNS is to look at packet traces with tools such as `wireshark <https://www.wireshark.org>`_ or `tcpdump <https://www.tcpdump.org>`_ These tools can capture packets in a network and also display and analyze their content. `Wireshark <https://www.wireshark.org>`_ provides a flexible Graphical User Interface that eases the analysis of the captured packets. The three questions below should help you to better understand the important fields of DNS messages.
0/4990 · 499
30
../../exercises/ipv6.rst:294
English
``p:12/64`` for the link between ``R1`` and ``R2``. On this subnet, ``R1`` uses address ``p:12::1`` while router ``R2`` uses address ``p:12::2``
0/1440 · 144
30
../../exercises/routing-protocols.rst:366
English
Router ``r2`` receives a similar request from ``fe80::481a:48ff:fed7:292e`` and replies by sending its routing table in a response message. Note that this message is sent to the link-local address of the requesting router.
0/2220 · 222
30
../../exercises/tcp-2.rst:191
English
Another usage of packetdrill_ is to explore how a TCP connection ends. The scripts below show how a TCP stack closes a TCP connection. The first example shows a local host that connects to a remote host and then closes the connection. The remote host acknowledges the ``FIN`` and later closes its direction of data transfer. This script is available from :download:`/exercises/packetdrill_scripts/local-close.pkt`.
0/4140 · 414
30
../../protocols/bgp.rst:99
English
The Internet uses a single interdomain routing protocol : the Border Gateway Protocol (BGP). The current version of BGP is defined in :rfc:`4271`. BGP differs from the intradomain routing protocols that we have already discussed in several ways. First, BGP is a `path-vector` protocol. When a BGP router advertises a route towards a prefix, it announces the IP prefix and the interdomain path used to reach this prefix. From BGP's point of view, each domain is identified by a unique `Autonomous System` (AS) number [#fasdomain]_ and the interdomain path contains the AS numbers of the transit domains that are used to reach the associated prefix. This interdomain path is called the `AS Path`. Thanks to these AS-Paths, BGP does not suffer from the count-to-infinity problems that affect distance vector routing protocols. Furthermore, the AS-Path can be used to implement some routing policies. Another difference between BGP and the intradomain routing protocols is that a BGP router does not send the entire contents of its routing table to its neighbors regularly. Given the size of the global Internet, routers would be overloaded by the number of BGP messages that they would need to process. BGP uses incremental updates, i.e. it only announces the routes that have changed to its neighbors.
0/12990 · 1299