GPRS roaming enables subscribers to access their GPRS
services while they are abroad or beyond the reach of their
home mobile network. It requires that a connection be made
between GPRS operators so that subscribers can move from
one network to another and yet still access their GPRS
services. GPRS roaming is based on bilateral relationships
between individual GPRS operators. It becomes complex and
expensive to maintain as the number of roaming partners
increases. The GPRS Roaming Exchange (GRX) therefore is
recommended for using GPRS roaming (Figure 2).