Gateway sizing in OCS R2. When estimating the amount of ports on campus, use these guidelines:
· Light telephony users (one PSTN call per hour) should allocate one port for every 15 users. For example, if you have 20 users, you will require a gateway with two ports.
· Moderate telephony users (two PSTN calls per hour) should allocate one port for every 10 users. For example, if you have 100 users, you will require a total of 10 ports allocated among one or more gateways.
· Heavy telephony users (three or more PSTN calls per hour) should allocate one port for every five users. For example, if you have 47,000 users, you will require a total of 9,400 ports allocated among at least 10 large gateways.
· Additional ports can be acquired as the number of users or amount of traffic in your organization increases.
For any given number of users you must support, you have the choice of deploying fewer, larger gateways, or smaller ones. As a rule, a minimum of two gateways for an organization is recommended in the event one goes down. Beyond that, the number and size of gateways that an organization deploys are going to vary widely, based on a careful analysis of each organization’s volume of telephone traffic.
It’s best to work with your partner to define how many gateways need to be deployed for your OCS installation given size and future utilization. Each basic gateway does need to have a corresponding Mediation server so keep that in mind. We will be working on other OCS R2 guidance over the next few weeks.