True ISP messaging server scalability means more than the ability to simply add mailboxes. It means adapting messaging services to accommodate real-world ISP growth patterns. InterMail's unique distributed architecture comfortably supports increasing numbers of users through dedicated, independently scalable server components. Each component can be distributed across multiple platforms for flexible configuration and system scaling. This allows hardware additions and resource expenditures to be strategically matched to the principal growth parameters that affect system performance:

• Increased message traffic - InterMail's Message Transport Agent servers efficiently handle inbound and outbound mail delivery and routing.
• Increased User Population - InterMail Message Store servers ensure reliable, persistent storage of messages.
• Changes in Frequency and Type of Access - InterMail's dedicated POP and IMAP Client Access servers enable mailboxes access through users' preferred protocols.

PERFORMANCE

The true measure of system performance occurs during peak loading, the times when the largest concentration of users send and read email. That's why performance claims based on theoretical average loading are irrelevant to real-world operation. And that's why InterMail's designers set out to provide the smoothest operation during critical peak system usage, avoiding the messaging delays and service interruptions that lead to high customer churn.

To achieve this goal, InterMail's sophisticated multi-threaded design allows each server to efficiently handle many simultaneous message deliveries and requests. The result is consistently high message throughput, even during the most demanding peak activity, a critical requirement for next-generation business messaging. Other design elements contributing to InterMail's consistent high performance include:

• Dynamic load balancing - makes the most efficient use of redundant system resources by steering tasks to idle components
• Powerful Integrated Services Directory - uses a series of local replicated directory caches for lightning-fast lookups for user mailbox locations
• Efficient queuing - employs multiple SMTP queue directories and per-domain deferred queues
• Streamlined message storage - storing a single linked copy of messages with multiple recipients reduces message traffic to a fraction of redundant message handling.