INF 123 SW ARCH, DIST SYS & INTEROP

LECTURE 13

Prof. Crista Lopes

Objectives

Understanding of Event-Based Architectures

Understanding practicalities of the Internet IP addresses routers security

Event-Based Architectures

An EBA is an architecture based on parts that interact solely or predominantly using event notifications, instead of direct method calls.

Event-Based Architectures

Component A Component B

Event Broker

1 23 4

1. Component A registers an event of type E2. Component B subscribes to that event type3. Component A raises that event4. Component B is notified of that event

Advantage over direct calls

Component A Component BE

Component C

E

…

coupling

Advantage over direct calls

Component A Component B

Event Broker

1 23 4

Component C…

No coupling!

2 4

Disadvantage over direct calls Less control on timing More difficult to understand program

flow

Events at different levels

Software architecture possibly with programming language

support

System architecture

SW Level without PL support

Object A Object B

Event Broker (your code or library object)

1 23 4

Object C…

2 4

SW Level with PL Support

Object A Object B

Event Broker

1 23 4

Object C…

2 4

Language runtime

Distributed System Level

Component A Component B

Event Broker (your component or someone else’s)

1 23 4

Component C…

2 4

Network

Part 2

The Internet

ipconfig @ home

myipaddress.com

myIPaddress.com

Your computer’s IP address is:

75.32.137.8

Hierarchical Identification

Home network Home network

ISP ISP

UCI

192.x.x.x 192.x.x.x

75.32.137.8 69.232.36.159128.195.54.203

128.195.54.203

Hierarchical Security

Home network Home network

ISP ISP

UCI

OpenSim Virtual World deployment

Home network Home network

ISP ISP

UCI

192.x.x.x 192.x.x.x

75.32.137.8 69.232.36.159ucigrid03.nacs.uci.edu

128.195.54.203

ResourceServices

Simulator Simulator

region registration

teleport

!

What the clients see