Protocols

Peers keep exchanging and forwarding state with random partners. The system ends up consistent and tolerates messages being dropped along the way. Everyone tells someone Each round a node picks a random peer and exchanges state, so a single fact spreads by repetition rather than by a single authoritative hop. Because the partner changes each round, information fans out geometrically: each round roughly doubles the nodes that know, which is why a new membership entry can reach a large cluster in a handful of rounds. The exchange is usually symmetrical, both sides learning from each other in one message pair, which keeps the network cheap and symmetric. It trades the guarantee of a single message delivered in order for a high, self-healing probability that the state eventually arrives. ...

The TCP three-way handshake establishes the two directions of a byte stream. Each endpoint supplies an initial sequence number and acknowledges the other endpoint’s number. Those are independent sequence spaces, not a shared wall clock. Applications do not need synchronized machine clocks to connect. Later sequence numbers identify bytes and support ordering, duplicate handling, acknowledgments, and retransmission within that connection. ...

A well-known URI gives software a conventional place to discover information associated with an origin. The reserved /.well-known/ prefix reduces collisions between independently designed protocols, and registered suffixes identify their defining specifications. The prefix is a naming mechanism, not an implementation or a guarantee of trustworthy content. A server must still route the selected endpoint correctly, and a client must interpret the response according to that endpoint’s own contract. ...

DNS supports both UDP and TCP. A server sets the TC flag when a response is truncated for the available message space. A client receiving that flag must handle the incomplete result, commonly by retrying over TCP. This is about the DNS response limit in use, not proof that the physical network cannot carry any larger UDP datagram. ...

An IPv6 host on an Ethernet link needs a link-layer destination before it can send a frame to a neighbor. Neighbor Discovery performs that address-resolution work using ICMPv6 Neighbor Solicitation and Neighbor Advertisement messages. It also covers functions beyond IPv4 ARP, including router discovery and neighbor reachability detection. Calling it merely “ARP with longer addresses” hides dependencies that matter when configuring an IPv6 network. ...

UDP carries discrete datagrams between transport endpoints. Its eight-byte header contains source port, destination port, length, and checksum fields. The protocol does not add TCP’s reliable ordered byte stream or its congestion-control behavior. This gives applications room to choose their own delivery policy, but it does not promise lower latency for every workload. A missing datagram can be more costly than a handshake when the application needs its contents. ...

EDNS extends DNS through an OPT pseudo-record. Among other information, a request can advertise the UDP payload size its sender is prepared to receive. This allows answers beyond the traditional 512-byte DNS limit. It is an advertisement within a DNS exchange, not a network path-MTU discovery protocol or a promise that every intervening device will deliver a datagram of that size. ...

Here, removing head-of-line blocking means removing HTTP response-order constraints on a shared connection. HTTP/2 does not remove TCP head-of-line blocking. A later response can finish while an earlier handler waits, but shared transport capacity, connection-level flow control, and application bottlenecks can still couple the streams. ...