Multiplexing Glossary

Canonical terms for this course. Definitions stay short and match lesson language.

Terms

Multiplexing
Combining many logical channels onto one shared connection by sending labeled pieces. Avoid: “merging everything into one blob.”
Demultiplexing
Sorting mixed pieces from one shared connection back into their original logical channels. Avoid: “decrypting” or “unpacking” unless those also happen separately.
Logical channel
One conversation or stream inside a shared connection, such as chat, file, or video.
Frame
A small labeled piece of data from a logical channel. A frame usually carries a channel label and may carry sequence information.
Channel label
Identifier that tells the receiver which logical channel a frame belongs to.
Head-of-line blocking
A delay where work at the front of a shared path makes later work wait, even when later work is small or urgent.
Scheduling
Choosing which logical channel gets to send the next frame on a shared connection.
Round-robin
A simple scheduling rule where each non-empty logical channel gets a turn before any channel repeats.
Quantum
The maximum number of frames a logical channel can send during one scheduler turn.
Port
A transport-layer number used by the operating system to route incoming network data to a listening app.
Socket
An endpoint label, usually combining protocol, local IP address, and local port, that an app uses to send or receive network data.
Listener
An app or process that has asked the operating system to receive traffic for a specific socket.
I/O multiplexing
A way for one thread to wait for readiness across many I/O sources, then handle whichever source is ready.
Blocking I/O
An operation that makes a thread wait until one specific I/O source is ready or complete.
Readiness
A signal that an I/O source can be read from or written to without the thread blindly waiting on that one source.
Event loop
A loop that waits for readiness or scheduled work, then runs the matching handler.
Task queue
A queue of normal callbacks waiting to run on the event loop.
Microtask queue
A higher-priority queue for promise reactions and similar work that runs before the next normal task.
HTTP/2 stream
A logical HTTP conversation identified by a stream ID inside one HTTP/2 connection.
Jitter
Uneven packet arrival timing that can make real-time media glitch unless buffered.
Jitter buffer
A short delay buffer that plays media packets by timestamp instead of raw arrival order.
Backpressure
A signal or limit that prevents fast senders from overwhelming slower receivers.

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