ListingsTech Technical Information

Managed Application

Most ListingTech customers elect to outsource the hosting and management of their public facing web site to ListingsTech. ListingsTech application servers are housed in a world-class, 376,000 square-foot data center located in Suwanee, Georgia. The data center provides:

• Multiple, redundant and diverse high-speed, fiber optic Internet connections
• State-of-the-art security systems and procedures
• Fully redundant power, cooling and environmental systems

The data center provides ListingsTech with primary and backup Internet connections. These two connections are connected to primary and backup firewall/load balancers. The firewall/load balancers are connected to a pair of Ethernet switches. Finally, our web server farm, application servers and database clusters are connected to the redundant switches. The switches and firewalls are used to create separate security domains (VLANs and dedicated IP subnets) for each hosted application.

When hosting with ListingTech, customers can choose the level of isolation (dedicated servers vs. shared servers), performance and reliability necessary to meet business goals and budget constraints. To increase security and isolation, customers can elect to host with dedicated hardware. To increase performance, customers can upgrade the CPU and RAM on dedicated servers and add load balanced web servers. Adding load balanced web servers increases reliability as well as performance. Clustered database servers will increase application reliability and minimize downtime for system maintenance tasks.

Core System Architecture

The ListingsTech engine is based on a fresh design using modern and state-of-the-art tools. The core development platform is Microsoft ASP.NET, version 2.0. The core programming language is C#. The Digital Camera Upload applet is an ActiveX control programmed in C++ with ATL. A strict 3+ tier model was used throughout - no UI code has SQL level access to the underlying database. Within the data model tier, all database access is done through a thin database independent wrapper over ADO.NET.

User Interface Design Goals

The design goals visible to the end user are:

• The site should appear attractive and professional
• Allow users to perform their tasks with a minimum of friction
• End user visible pages should load quickly (but analog modem users are not a target audience)
• End user pages should support common browsers
• Administrator only pages need only support IE 6 and later, but support for all common browsers remains the ideal
• All pages should support systems with common color depths and screen dimensions
• All pages should support increasing the text size via the browser to support low vision users
• Most content pages should use a layout that takes advantage of larger screens (favor flow layouts over absolute positioning)

The total graphic design of the system is created with a combination of:

• Style Sheets (CSS)
• Images (backgrounds, logos, icons, etc.)
• aspx templates (contain a mixture of HTML and C# code)
• Programming code
• End user created templates for home pages, search results, listings, agent directories and articles (contain a mixture of HTML and template markers)

Template and Database Driven

The content of all end user visible pages is created by merging templates with database content. The templates and most images are also stored within the database. Because the templates are editable by office administrators, almost any look and feel can be created. Original templates created by ListingsTech generally favor CSS with style sheets and flow layout as described above.