1. INF 123 SW ARCH, DIST SYS & INTEROP LECTURE 13 Prof. Crista Lopes

2. Objectives  Understanding of Event-Based Architectures  Understanding practicalities of the Internet  IP addresses  routers  security

3. Event-Based Architectures  An EBA is an architecture based on parts that interact solely or predominantly using event notifications, instead of direct method calls.

4. Event-Based Architectures Component AComponent B Event Broker 1 2 3 4 1.Component A registers an event of type E 2.Component B subscribes to that event type 3.Component A raises that event 4.Component B is notified of that event

5. Advantage over direct calls Component AComponent B E Component C E … coupling

6. Advantage over direct calls Component AComponent B Event Broker 1 2 3 4 Component C … No coupling! 2 4

7. Disadvantage over direct calls  Less control on timing  More difficult to understand program flow

8. Events at different levels  Software architecture  possibly with programming language support  System architecture

9. SW Level without PL support Object AObject B Event Broker (your code or library object) 1 2 3 4 Object C … 2 4

10. SW Level with PL Support Object AObject B Event Broker 1 2 3 4 Object C … 2 4 Language runtime

11. Distributed System Level Component AComponent B Event Broker (your component or someone else’s) 1 2 3 4 Component C … 2 4 Network

12. Part 2 The Internet

13. ipconfig @ home

14. myipaddress.com myIPaddress.com Your computer’s IP address is: 75.32.137.8

15. Hierarchical Identification Home network ISP UCI 192.x.x.x 75.32.137.8 69.232.36.159 128.195.54.203

16. Hierarchical Security Home network ISP UCI

17. OpenSim Virtual World deployment Home network ISP UCI 192.x.x.x 75.32.137.8 69.232.36.159 ucigrid03.nacs.uci.edu 128.195.54.203 Resource Services Resource Services Simulator region registration teleport !

18. What the clients see