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diff --git a/content/docs/network_protocols.md b/content/docs/network_protocols.md deleted file mode 100644 index d162945..0000000 --- a/content/docs/network_protocols.md +++ /dev/null @@ -1,135 +0,0 @@ ---- -title: "Packet network protocols" -author: "Dimitri Staessens" -description: "what" -date: 2019-09-05 -#type: page -draft: false ---- - -Packet switched networks move data between two applications using -_protocols_, which specify where to move the data and how to do it. -The Internet famously uses the Internet Protocol, IP (versions 4 and -6, which are mutually incompatible, so in essence, there is not a -single Internet, there are two!) as the network protocol that -specifies how to move packets from point _A_ to point _B_. On top, it -has the Transport Control Protocol (TCP) that takes care of things -when IP packets get lost. TCP also does some other neat things, like -making sure that a client does not send faster than a server can -process, usually called _flow control_; and making sure that the -network doesn't get overwhelmed by its users, usually called -_congestion control_. - -The IPv4 protocol is specified in -[RFC791](https://tools.ietf.org/html/rfc791), and its _header_ is -shown here: - -``` - 0 1 2 3 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Version| IHL |Type of Service| Total Length | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Identification |Flags| Fragment Offset | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Time to Live | Protocol | Header Checksum | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Source Address | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Destination Address | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Options | Padding | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -``` - -The IPv6 protocol is specified in -[RFC2460](https://tools.ietf.org/html/rfc2460), and its header format -is: - -``` - 0 1 2 3 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |Version| Traffic Class | Flow Label | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Payload Length | Next Header | Hop Limit | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Source Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + + - | | - + Destination Address + - | | - + + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - -``` - -For a detailed description of what all the fields in this protocol -mean, we gladly refer you to the RFCs or the wikipedia pages ( -[IPv4](https://en.wikipedia.org/wiki/IPv4) and -[IPv6](https://en.wikipedia.org/wiki/IPv6)). The most interesting -fact about the jump from IPv4 to IPv6 is that the protocol got -noticeably simpler. - -As Ouroboros tries to preserve privacy as much as possible, it has an -*absolutely minimal network protocol* (it's also configurable, this is -the 64 bit address, 16 bit EID version): - -``` - 0 1 2 3 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | | - + Destination Address + - | | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Time-to-Live | QoS | ECN | EID | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | EID | - +-+-+-+-+-+-+-+-+ -``` - -The fields are: - -* Destination address: This specifies the address to forward the - packet to. The width of this field is configurable based on various - preferences and the size of the envisioned network. The Ouroboros - default is 64 bits. Note that there is _no source address_, this is - agreed upon during _flow allocation_. - -* Time-to-Live: Similar to IPv4 and IPv6 (where this field is called - Hop Limit), this ensures that packets don't get forwarded forever in - the network, for instance due to (transient) loops in the forwarding - path. - -* QoS: Ouroboros supports Quality of Service via a number of methods - (out of scope for this page), and this field is used to prioritize - scheduling of the packets when forwarding. For instance, if the - network gets congested and queues start filling up, higher priority - packets (e.g. a voice call) get scheduled more often than lower - priority packets (e.g. a file download). - -* ECN: This field specifies Explicit Congestion Notification (ECN), - with similar intent as the ECN bits in the DSCP field in IPv4 / ToS - field in IPv6. It has 8-bit width as a default, and gets set higher - as packets are deeper and deeper in a forwarding queue. Ouroboros - enforces Forward ECN (FECN). - -* EID: The Endpoint Identifier (EID) field specified the endpoint for - which to deliver the packet. The width of this field is - configurable, the values of this field is chosen by the endpoints at - _flow allocation_. It can be thought of as an ephemeral port. - ---- -Changelog: - -2019 09 05: Initial version.
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