An ingress router is a label switch router that is a starting point (source) for a given label-switched path (LSP). An ingress router may be an egress router or an intermediate router for any other LSP(s). Hence the role of ingress and egress routers is LSP specific. Usually, the MPLS label is attached with an IP packet at the ingress router and removed at the egress router, whereas label swapping is performed on the intermediate routers. However, in special cases (such as LSP Hierarchy in RFC 4206, LSP Stitching [1] and MPLS local protection) the ingress router could be pushing label in label stack of an already existing MPLS packet (instead of an IP packet). Note that, although the ingress router is the starting point of an LSP, it may or may not be the source of the under-lying IP packets.
computer science
Ingress router
Ingress router is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ingress router rather than just read about it. In short: An ingress router is a label switch router that is a starting point (source) for a given label-switched path (LSP). An ingress router may be an egress router or an intermediate router for any other LSP(s).
Key takeaways
- Ingress router belongs to computer science; place it in that map before memorising details.
- Learn the definition first, then one example that makes the definition concrete.
- Connect Ingress router to a quantity you can measure, compute or draw — that is where exam questions come from.
- Reproduce the core statement of Ingress router from memory before moving on to harder problems.
Reference excerpt
Worked examples
Example 1 — a first encounter with Ingress router
Start with the simplest possible case. Write down what Ingress router claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.
Example 2 — changing one variable
Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ingress router before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.
Example 3 — an exam-style question
Typical questions about Ingress router ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.
Applications of Ingress router
- In research
- Ingress router appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
- In technology and industry
- Engineering practice reuses Ingress router in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
- In the classroom
- Ingress router is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer network stubs, MPLS networking, so understanding it makes those chapters shorter.
- In everyday life
- Look for Ingress router outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Ingress router in 20 minutes
- Read the reference excerpt below once, without taking notes.
- Close the page and write down what Ingress router means in your own words.
- Compare your version with the excerpt and mark what you missed.
- Work through the three examples above with pen and paper.
- Explain Ingress router out loud to somebody else — or to Teacher Smith in the lgStudy chat.
Frequently asked questions
What is Ingress router in simple terms?
An ingress router is a label switch router that is a starting point (source) for a given label-switched path (LSP). An ingress router may be an egress router or an intermediate router for any other LSP(s).
Why does Ingress router matter?
Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.
How should I study Ingress router?
Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.
What does this page cover?
It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ingress router.
Tags
- Computer network stubs
- MPLS networking