Yesterday in my mail I received the September 2006 issue of Mobile Communications International. The advertisement by Huawei on the back of the magazine caught my eye. The copy began:

During the holy season, Muslims embark on a journey of prayer to the Hajj. At this time, over 3 million pilgrims use their mobile phones, all at the same time, within a 10km radius. This creates a unique challenge for network operators. [The ad then described the proven reliability of Huewei's Mobile Softswitch, and concluded:] ‘there’s no way we’d let over 3 million pilgrims down during one of the most important events in their lives.’

I did a little digging and found a longer description here of the surge of pilgrim phoning, which occurred from January 8-13, 2006:

In 2006 Haj season, 3 million pilgrims, up 20% than last year, gathered in the holy sites which is 5 square kilometers around. Since the mobile users made calls at the same time period, it caused obvious peak traffic; millions of mobile users moved to the same direction at the same time according to the pilgrimage rite, so a large amount of location update and handover were generated. Moreover, since the pilgrims come from different countries, the quantity of short messages jumped 10 times over the average.