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diff --git a/content/docs/protocols.md b/content/docs/protocols.md deleted file mode 100644 index 571ba98..0000000 --- a/content/docs/protocols.md +++ /dev/null @@ -1,116 +0,0 @@ ---- -title: "Ouroboros packet network protocols" -author: "Dimitri Staessens" -description: "protocols" -date: 2019-09-06 -#type: page -draft: false ---- - -# Network protocol - -As Ouroboros tries to preserve privacy as much as possible, it has an -*absolutely minimal network protocol*: - -``` - 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 5 fields in the Ouroboros network protocol 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. The Ouroboros default for the width is one octet (byte). - -* 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). By default this field takes - one octet. - -* ECN: This field specifies Explicit Congestion Notification (ECN), - with similar intent as the ECN bits in the Type-of-Service field in - IPv4 / Traffic Class field in IPv6. The Ouroboros ECN field is by - default one octet wide, and its value is set to an increasing value - as packets are queued deeper and deeper in a congested routers' - forwarding queues. 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 figure shows 16 bits). The values of this field is chosen by - the endpoints, usually at _flow allocation_. It can be thought of as - similar to an ephemeral port. However, in Ouroboros there is no - hardcoded or standardized mapping of an EID to an application. - -# Transport protocol - -Packet switched networks use transport protocols on top of their -network protocol in order to deal with lost or corrupted packets. - -The Ouroboros Transport protocol (called the _Flow and Retransmission -Control Protocol_, FRCP) has only 4 fields: - -``` - 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 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Flags | Window | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Sequence Number | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Acknowledgment Number | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - -``` - -* Flags: There are 7 flags defined for FRCP. - - - DATA: Indicates that the packet is carrying data (allows for 0 - length data). - - - DRF : Data Run Flag, indicates that there are no unacknowledged - packets in flight for this connection. - - - ACK : Indicates that this packet carries an acknowledgment. - - FC : Indicates that this packet updates the flow control window. - - RDVZ: Rendez-vous, this is used to break a zero-window deadlock - that can arise when an update to the flow control window - gets lost. RDVZ packets must be ACK'd. - - FFGM: First Fragment, this packet contains the first fragment of - a fragmented payload. - - MFGM: More Fragments, this packet is not the last fragment of a - fragmented payload. - -* Window: This updates the flow control window. - -* Sequence Number: This is a monotonically increasing sequence number - used to (re)order the packets at the receiver. - -* Acknowledgment Number: This is set by the receiver to indicate the - highest sequence number that was received in - order. - ---- -Changelog: - -2019 09 05: Initial version.<br> -2019 09 06: Added section on transport protocol.
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