Before discussing architectural changes to your mail routing topology and SMTP MTA system design, we should examine what motivates you to look for a solution. Mail routing delays, for example, are typically either configuration issues or capacity problems relating to either network or server capacity.

Mail routing delays are the most common issue but they are not caused by product limitations. Mail routing configuration and inefficient mail routing can be corrected. Capacity issues can be addressed simply by upgrading servers or networks. Each customer facing this problem needs to compare the costs of installing, administering, supporting, and maintaining multiple Internet connections and SMTP MTAs with the costs of resolving configuration and capacity problems. I don't recommend taking any action until those specific problems you have noted are clearly understood.

Capacity planning is always an issue where the ever rising volume of Internet email is concerned. The least effective methodology is to determine, based on the negative impact on users and your information systems department, that capacity problems exist. As the market and the products continue to mature, and as their focus on Internet messaging technologies continues to sharpen, we'll have better tools for monitoring and data collection -- and these tools can be utilized for capacity planning.

The best way to make architectural decisions for Domino and Internet messaging (i.e., centralization versus distribution of SMTP MTAs) is to combine financial factors and capacity planning data. The methodology I use use for capacity planning is to collect and apply messaging statistics to create a mathematical model of the messaging environment.

The capacity model can be used to predict required network bandwidth and server capacities, as well as to project "what if?" scenarios for architectural design purposes. One of the main benefits of capacity planning, however, is the ability to predict when the capacity of networks or servers will be exceeded and to respond before users are negatively impacted.

Ron Herardian (rherardi@gssnet.com)
Global System Services Corporation (GSS)
http://www.gssnet.com/