• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Tim Cooke
  • Ron McLeod
  • Jeanne Boyarsky
  • Paul Clapham
Sheriffs:
  • Liutauras Vilda
  • Henry Wong
  • Devaka Cooray
Saloon Keepers:
  • Tim Moores
  • Stephan van Hulst
  • Tim Holloway
  • Al Hobbs
  • Carey Brown
Bartenders:
  • Piet Souris
  • Mikalai Zaikin
  • Himai Minh

Three-Tier vs. Multi-Tier

 
Greenhorn
Posts: 15
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
For purposes of the Part 1 exam, is there a difference between a
three-tier architecture and a multi-tier architecture?
Section 2 of the objectives indicates that they are different, however
most of the articles and books that I have lump them together (as N-tier).
Can a three-tier architecture be horizontally scaled? i.e. if you
have a web-based system and decide to use a load balancer to employ
multiple web servers, is it still a three-tier system or do the extra
machines make it multi-tier?
Any help is greatly appreciated.
Thanks!
 
Sheriff
Posts: 5782
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
N-tier is a generalization( and inclusive ) of three-tier architecture and I prefer using the former than latter. N-tier systems often extend the standard three-tiers by including additional resources such as leagacy systems(EIS), service-based components(EAI) etc.
Tiers not necessarily are aligned with physical boundaries. For instance, you can have a single instance of an app server host both the web tier and the ejb tier. Tiers are conceptual architectural lines drawn mostly around the functionality provided by the components that make up the tier. Therefore, simply adding multiple web servers do not add additional tiers to the architecture.
Cheers,
 
Greenhorn
Posts: 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
What if you have multiple client types making a request... i.e. a thin web client and a thick gui client.
Also, what if your business tier broadcast or publish messages to a topic or queue? Do you consider the MQ server a separate tier?
 
reply
    Bookmark Topic Watch Topic
  • New Topic