border gateway dimensioning for grx

[buihu dat]

We are setting-up a grx (gprs roaming exchange) with grx operator, another telco and mms vendor. Problem is i need to dimension the bg. Initially we have 3 connections and have 100,000 subs, data that will traverse are streaming, gprs, mms and internet.

Problem how to dimension and bg? can anyone give suggestions on how to compute kbps to pps or other parameters?

Please advice.

thanks.