---
title: "Short note: SOA and SOAP"
subject: "Web Technology"
chapter: 8
key: "semester_7/web_technology:short-note-soa-soap"
source: https://www.bctengineer.com/q/semester_7/web_technology/short-note-soa-soap
site: BCT Engineering
---

# Short note: SOA and SOAP

Web Technology · Chapter 8: Web services

- Asked in: 2074 Chaitra, 4 marks
- Video: [Service Oriented Architecture (SOA) Simplified.](https://www.youtube.com/watch?v=PA9RjHI463g) — Coding Env
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/web_technology/short-note-soa-soap
- Whole chapter: https://www.bctengineer.com/md/semester_7/web_technology/chapter-8

## Question

Write a short note on SOA and SOAP.

## Short answer

SOA is a design style where software is built as loosely coupled, reusable services with published interfaces, enabling platform-independent integration. SOAP is an XML-based messaging protocol with an Envelope containing a Header and Body, used for communication between services, often over HTTP.

## Answer

#### SOA (Service-Oriented Architecture)
**SOA** is a design style in which software is built as a set of loosely coupled, reusable **services**. Each service performs one business function (for example "check balance"), has a published interface, and can be used by other applications over a network irrespective of platform or language.

```text
        Service registry (UDDI)
         ^ publish      | find
         |              v
 Service provider <-- Service consumer
          bind and call (SOAP / HTTP)
```
Three roles: **service provider** (creates and publishes the service), **service registry** (directory where services are listed), **service consumer/requester** (finds and invokes it).

Benefits: reuse, interoperability, flexibility, easier integration of legacy systems, scalability.

#### SOAP (Simple Object Access Protocol)
**SOAP** is an XML-based protocol for exchanging messages between services, usually over HTTP. A SOAP message has an **Envelope** containing an optional **Header** and a mandatory **Body** (and a Fault element for errors).
```xml
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
  <soap:Body><GetStudent><Id>5</Id></GetStudent></soap:Body>
</soap:Envelope>
```

#### Relation
SOA is the architectural idea; SOAP is one standard way (with WSDL and UDDI) of implementing communication between the services in a SOA. Web services can also be provided in a SOA using REST.

## Check yourself

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

1. What is SOA?
   A. A protocol for XML messages
   B. A design style where software is built from loosely coupled, reusable services
   C. A language to describe web pages
   D. A database schema
   Answer: B. SOA builds software from loosely coupled services, each performing one business function with a published interface. (Key point: SOA definition)

2. Which is the correct set of SOA roles?
   A. Client, router, firewall
   B. Service provider, service registry, service consumer
   C. Parser, compiler, linker
   D. Envelope, header, body
   Answer: B. A provider publishes the service, a registry lists it, and a consumer finds and invokes it. (Key point: SOA roles)

3. How are SOA and SOAP related?
   A. SOAP is the architectural idea; SOA is a message format
   B. SOA is the architectural idea; SOAP is one standard way to implement communication between services
   C. They are the same thing
   D. SOA can only be done with SOAP
   Answer: B. SOAP is one way of implementing SOA; REST can also be used. (Key point: SOAP and SOA relation)