---
title: "Link analysis and search engine architecture"
subject: "Information System"
chapter: 7
key: "semester_8/information_system:link-analysis-search-engine-architecture"
source: https://www.bctengineer.com/q/semester_8/information_system/link-analysis-search-engine-architecture
site: BCT Engineering
---

# Link analysis and search engine architecture

Information System · Chapter 7: Web based information system and navigation

- Asked in: 2072 Magh, 3+4 marks
- Video: [Link Analysis](https://www.youtube.com/watch?v=xvUjNmwcuUM) — Ekeeda
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/information_system/link-analysis-search-engine-architecture
- Whole chapter: https://www.bctengineer.com/md/semester_8/information_system/chapter-7

## Question

State Link Analysis in Web Search. How does a Search Engine Work? Discuss its architecture.

## Short answer

Link analysis in web search uses hyperlinks as votes to rank pages (PageRank, HITS). A search engine works by crawling pages, indexing text into an inverted index, and ranking by content and link importance. Its architecture includes crawler, page store, indexer, inverted index with link data, and query processor/ranker.

## Answer

#### Link analysis in web search
**Link analysis** uses the hyperlink structure of the web to judge the importance and relevance of pages. Search engines treat a link as a recommendation: pages with many links from good pages are ranked higher. The main algorithms are PageRank and HITS (hubs and authorities). The anchor text of links also helps describe the target page.

#### How a search engine works
1. **Crawling:** a crawler (spider) starts from seed URLs, downloads pages and follows links to find new pages.
2. **Indexing:** text is extracted, cleaned, tokenised, stemmed, and stored in an **inverted index** (word -> list of pages and positions). Link data and other features are stored too.
3. **Ranking:** relevance of pages to the query is calculated using content (TF-IDF) and link analysis (PageRank).
4. **Query processing:** the user's query is analysed, matching documents are found in the index, ranked and displayed with snippets.

#### Architecture
```text
 Web --> [Crawler] --> [Page store]
                           |
                      [Indexer]
                           |
            [Inverted index + Link data]
                           |
 User --> [Query processor / Ranker] --> Results
```

#### Components
- **Crawler/spider** and URL scheduler.
- **Document repository** (cache of pages).
- **Indexer** and link analyser (computes PageRank).
- **Index/database** (distributed across many servers).
- **Query engine and ranking module,** and user interface.
- Supporting parts: spam detection, caching of popular queries and freshness updates.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How does a search engine use links?
   A. It ignores links completely
   B. It ranks pages with fewest links first
   C. It treats a link as a recommendation, so pages with links from good pages rank higher
   D. It uses links only to colour results
   Answer: C. Link analysis uses PageRank and HITS to judge importance. (Key point: Link as recommendation)

2. What is the correct order of search engine steps?
   A. Indexing, crawling, display, ranking
   B. Crawling, indexing, ranking, query processing
   C. Query processing, crawling, indexing, ranking
   D. Ranking, crawling, query, indexing
   Answer: B. Pages are crawled, indexed, scored, and then matched to queries. (Key point: Search steps)

3. What does an inverted index store?
   A. Each word with the list of pages and positions where it occurs
   B. Each page with its colour
   C. Each user with their passwords
   D. Each server with its IP only
   Answer: A. It maps words to pages for fast lookup. (Key point: Inverted index)

4. What does a crawler (spider) do?
   A. Answers user queries
   B. Computes TF-IDF only
   C. Displays snippets
   D. Starts from seed URLs, downloads pages and follows links to find new pages
   Answer: D. Crawling collects pages for the indexer. (Key point: Crawler)

## Related in Information System

- [Web structure and search engine](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Aweb-organization-search-engine-working) — Information System, chapter 7
- [Link analysis for the web](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Alink-analysis-web-environment) — Information System, chapter 7, asked 4×
- [Link analysis in web vs cloud](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Alink-analysis-web-vs-cloud) — Information System, chapter 7

## Related in other subjects

- [Web architecture and web-tier components](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Aweb-architecture-tiers) — Web Technology, chapter 2
- [Web services architecture; SOAP and WSDL roles](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Aweb-services-soap-wsdl) — Web Technology, chapter 8
- [Web log mining and WWW mining architecture](https://www.bctengineer.com/question.md?key=semester_7%2Fdata_mining%3Aweb-log-mining-architecture) — Data Mining, chapter 7
- [How the Internet and Web work together](https://www.bctengineer.com/question.md?key=semester_7%2Fweb_technology%3Ainternet-and-web-together) — Web Technology, chapter 1