Johannesburg - South Africa's third mobile operator Cell C on Wednesday chalked off cities number five and six by announcing the launch of its HSPA+ 900 network in Durban and Pietermaritzburg.This follows successful launches in Port Elizabeth, Bloemfontein, East London and Cape Town in recent weeks. Cell C CEO Lars P Reichelt said: "Our 4GS network today covers around 98% and 93% of the city population of Durban and Pietermaritzburg respectively, and by January 2011 will cover 99% of both cities and their surrounding areas. In real use conditions Cell C's new HSPA+ network shows average speeds of between 6Mbps and 7Mbps in downloads and speeds of between 1.5 Mbps and 2.5 Mbps for uploads, with a maximum technical throughput of 21Mbps in Durban and Pietermaritzburg, the group said. "As South Africa's third largest city and the largest port on the eastern African seaboard, the start of our network in Durban is a boon for business and private customers alike. The capital of the KwaZulu-Natal province, Pietermaritzburg is now also able to benefit from our new network," Reichelt said.The high-speed network, dubbed 4GS - 4 Great Speed and 4 Great Service - uses multi standard radio technology to support the HSPA+ 900 MHz network. The first phase of the 4GS network rollout, set for completion by the end of 2010, will cover approximately 34% of the South African population, with the network being launched on a city-by-city basis. The mobile operator said it would continue to expand its network rollout and aims to cover 67% of the population by mid 2011.