They mostly do phone or webex (video) interviews. Every interview I've had with Cisco for internship positions have been conversation based, with not too much structure. We go through what is on my resume, which all lead to different free-flowing conversations.
Each interview is great especially if you're a good conversationalist, but the follow-up is horrible. They would take a very long time to get back to me, and some of my contacts never did reply or call back. It was very discouraging and frustrating, especially when they cut the program I was applying for by a third...which brings up another issue with Cisco: job security.
They frequently make large cuts solely based on weighing an employees financial benefit versus cost to Cisco, regardless of other factors, such as how long you've been with the company. It's a great company to work for, just know what you're getting into before applying.