Cat: Is it possible to pass the CCNA without working on network gear on a daily basis? Absolutely. Some practical hands-on would help when you are nearing an exam, just to nail the concepts down, but you do not need to use it every day.
Moderator-Keith: Pre-submitted question: What is the typical thing that network administrators do wrong when implementing deep packet inspection? This really depends on what you are using DPI for. Some people use it for threat detection, trying to see complex attack vectors. Others use DPI to gain more visibility in a passive sense into the types of applications their user community is using, and with what frequency and impact on the network. This can aid in setting usage policies in the future, for example.
Jeffgratton: What would be the best advice you can give to prepare for the CCIE certification? For the CCIE, you definitely need a lot of hands-on experience. Assuming you are talking about the Routing & Switching CCIE, its good to look at both enterprise forms of routing, such as OSPF and EIGRP, as well as service provider... such as MPLS and BGP. For switching, you need to really get a handle on switching topologies and scenarios. The best things to prepare for the actual exam are practice exams, and also a practice rack of equipment. Get your colleagues to "break" stuff in the rack and then troubleshoot it.
Larry: Are there any "networking for beginners" books you feel would make great reference books? LOL. OK, time for a shameless plug. My co-author and I just published a book called Cisco Networking Simplified, which covers a lot of networking technologies each in five pages. It's meant for people fairly new to networking.
TomSmall: How do you see convergence of presence technologies impacting networking in the future? I think presence will have huge impacts on the next generation of networks. Networks will become intelligent about where people are (office, home, mobile), what devices they are using (PDA, laptop, phone), and what applications are being used. The network will aid applications using presence information. For example: "Hey, John is on a mobile device at a hotspot over a VPN, let's not offer his device the high-def video call, let's negotiate it down to low-def." Presence will also be able to let people customize how they prefer to be communicated with. For example, while I am in a meeting I prefer IM and e-mail. While I am at home I prefer videoconferencing.
Moderator-Keith: Pre-submitted question: VoIP has become mainstream, but telepresence not so much yet. What's holding most companies back from implementing it and why should they move forward with it? If anyone caught the session at VoiceCon 2008 last week where Vice President Al Gore and John Chambers talked to 2500 people at VoiceCon using Telepresence (you can catch a rebroadcast here), it's clear that more and more collaboration technologies like telepresence will become increasingly critical to solving some of our planet's large challenges in terms of global warming and energy prices. Telepresence is actually ramping up fairly quickly with our customers. One of the challenges is it's hard to understand what is different about telepresence until you experience it first-hand. People imagine that it's just another videoconferencing solution, and it's quite different from that. Within Cisco we have held some 80,000 hours of meetings over telepresence, saving $100 million in travel, AND saving thousands of tons of carbon emissions. We believe it is critical to foster as many collaboration technologies as possible, and we will continue to try and make telepresence one of the leading collaboration technologies in the industry.
Moderator-Keith: Pre-submitted question: How is the trend of virtualization changing network architecture and design, and what are most network administrators not understanding about this change? Quite a few people still look at virtualization as a data center only technology, or a way for multiple divisions of a company to share part of a network infrastructure, like a WAN. While those are great examples, there are more and more examples where virtualization technology solves problems, including guest access and putting "private" applications on the network such as IP Video Surveillance. The key is to start thinking of the network as a single physical infrastructure that needs to support multiple network partitions, and make your network architecture and planning decisions around that.