in ZTE SDR, 24TRX —> 1E1 (IPoE1) is true only when we consider voice, without any GPRS or EDGE PDCH ( I assume ur GUP/UPPB capacity in iBSC well dimensioned)….As I rememebr for one GPRS PDCH —> 16Kbps in Abis and EDGE PDCH —> 32Kbps in Abis…these PDCH must be considererd aside from Voice…so in this case 1E1 will give far less then 24TRX, if not more then 4PDCH/Cell just consider 22TRX/E1 or even less…..Hope this helps