Though there are thousands of people working in our industry, Network World chose 50 as the most powerful - and among them are several who are helping to shape LANs.In its annual Power Issue, Network World does its best to shine a spotlight on the movers and shakers throughout all aspects of networking. No. 1 on our list is Cisco CEO John Chambers - sure, that\u2019s a given.Beyond Chambers, it gets more interesting. John McHugh is there, the vice president\u00a0and general manager of HP\u2019s ProCurve Networking group. Though other companies had a head start, the article notes that HP has managed to fight its way to second place in the Ethernet switch market, in terms of worldwide port shipments, and that\u2019s no small feat. ProCurve has managed to keep prices down while raising functionality in many areas.First place does belong to Cisco, and there are a couple of other Cisco folks on the list. Charlie Giancarlo is the company\u2019s chief development officer, and he is busy filling the large shoes of Mario Mazzola, who retired last year.Also there is Jayshree Ullal, who came to Cisco via the Fast Ethernet start-up Crescendo Communications more than a decade ago. Jayshree gets her own in-depth profile in the Power Issue. As the profile says, she now heads a business unit that covers security, storage - and switching.Interestingly, if you ask users to pick the most powerful vendors - which we did - they\u2019ll say Cisco is powerful, yet vulnerable. In particular, they name security as vulnerable for Cisco. The challenge will be for the company to get its security efforts to the level of its switching efforts.For the full Power Issue, it might be best to start at the beginning.