Recently I purchased few Huawei E173 modems for my organization. Configuring them on ubuntu was the next part which I need to take care of. There were couple of solutions available out there where i searched, but this one was the very basic one and didn't needed any special drivers or installation of any special software.
I am sure you must have seen the problem when you changed the IP address of the computer host, and the host went off the network. The reason is pretty simple that the router haven't go the updated it's arp table with the right Mac address and IP address combination, means the old IP address is still associated with the Mac address of your system. Usually this is taken care automatically but sometimes if it's not happening then there is a way to fix this, by forcing the router to update it's arp table.