Definition
Kendall’s Notation is a standard system for describing and classifying Queuing Systems (M&S) based on their arrival, service, and capacity characteristics. It is written as:
A / B / c / N / K
Why It Matters
Queues are everywhere—from servers to grocery stores. Kendall’s notation provides the shorthand language needed to model these systems, allowing engineers to predict wait times and optimize throughput before a single customer ever arrives.
Core Concepts
- A: Inter-arrival time distribution.
- B: Service time distribution.
- c: Number of parallel servers.
- N: Queue capacity (often infinite if omitted).
- K: Size of the calling population (often infinite if omitted).
- Common Codes:
- M: Markovian (Poisson/Exponential).
- D: Deterministic (Fixed).
- G: General distribution.
- E: Erlang distribution.
- How to read: “The symbol E k, representing the Erlang distribution.”
- Meaning / when to use: Erlang- distribution—models service times as the sum of exponential stages; more flexible than M, smoother than deterministic.