Upstream and Downstream definition

Question

in my organization they tend to use a nomenclature of "downstream" and "upstream" when they talk about communications between systems. What is the definition of these concepts? Is this standard concepts in the world of IT-development?

Diminish

Can you use it in a sentence? – Merrygoround

programmers.stackexchange.com/questions/71080/… – Landre

Yes, they tend to use it in this fashion: "We need a test environment that is seperated from DTAP, both upstream and downstream". "No, we cant deploy because we have problems downstream/upstream". – Diminish

Answer 1

I know this is old but I think the other answer has it the wrong way around. Think of it this way - if you are upstream from something what you do can affect it and equally something upstream from you affects you but something downstream can't.

So to use the same method, given a system S:

Upstream - something which S depends on (as it's actions "flow down" to S)

Downstream - something which depends on S (as S's actions "flow down" to it)

Dormeuse

Yes, I agree with Matt. I see it as this: A --> B --> C A is the source for B, B is the source for C. So, the chain goes from A to B to C. From A to B and to B to C I consider downstream, like 'how the river flows'. GOing in the opposite direction is going upstream. Though I know in my company other people also use it the other way around... – Narration

Answer 2

To simplify things, let's say we are talking about a system S.

Upstream - Something which depends on S

Downstream - Something which S depends on

Conveyancing

So in a JavaEE application... the equivalent would be... if we are talking about EJB beans.... then the DB is downstream and JSF is upstream?? But upstream/downstream is a matter of systems and not components of a system, right? – Diminish

I believe the more common interpretation is the one that Matt posted in the other answer. I elaborated on it in this blog post because it kept confusing me, too. – Imaginary

This is wrong. Nothing downstream can be a dependency of yours. They are dependents... not dependencies. – Nucleate

This answer is obviously wrong. When you are at a real stream or a river, if you throw something into it, it would flow downstream. Changes can affect only downstream dependents. Dependencies are upstream. – Bananas