sentence: its principal competitors include : within the consumer markets , companies such as apple , belkin , d-link , linksys , roku , and western digital ; and within the business markets , companies such as allied telesis , barracuda , buffalo , data robotics , dell , d-link , fortinet , hewlett-packard , huawei , cisco systems , linksys , qnap systems , seagate technology , sonicwall , synology , watchguard and western digital ; and within the service provider markets , companies such as actiontec , arris , comtrend , d-link , hitron , huawei , motorola solutions , pace , sagem , scientific atlanta - a cisco company , smc networks , technicolor , ubee , compal broadband , zte and zyxel .