In order to upgrade firmware at network elements in a communications network a network upgrade protocol agent is installed on each network element. These agents run an upgrade protocol which allows an upgrade to be loaded onto a first network element and then broadcast through the network. The protocol includes notification messages, which change the state of the network elements to which the upgrade relates, download messages which include the firmware upgrade, apply messages which instruct relevant network elements to apply the upgrade, and inventory messages which send an inventory of firmware stored at a network element to neighboring elements to enable a determination to be made of whether a network element has received all relevant firmware upgrades.