Since the year 2000 GSM operators have been using GRX (GPRS Roaming Exchange) network for routing the IP based commercial roaming traffic between visited and home operators.
从 2000 年起，GSM 运营商已经开始使用 GRX（GPRS 漫游交换）网络来在拜访和归属运营商之间对基于 IP 的商业漫游流量进行路由。