1. 

   W Boudville
   August 7th, 2010 - 23:08

   The book is more than just material for passing an exam. There is good background about the theory of network configuration and routing. So the text can be read usefully as a germane descriptor of contemporary network design, even if you do not need or want to take the exam.

   A vital idea in the book is the migration from networks built using Layer 2 devices to those for Layer 3. Cisco now has Layer 3 switches of comparable performance to Layer 2 elements. The key difference is that Layer 3 switching can use the IP addresses in the packet. Better yet are Layer 4 and 7 switches, which, unsurprisingly, Cisco also offers. The Layer 4 switch can access the port number in TCP or UDP packets, as an extra filtering criterion. While a Layer 7 switch goes further by being able to dig into the payload itself for more embedded data, like whether http or https or ssh is being used. Unlike the Layer 3 switches, the book does not seem to claim that the Layer 4 or 7 switches are as fast as the Layer 2 switches. Unsurprising, given the potentially more extensive processing of each packet implied by the higher layers.

   Chapter 3 goes well into the various spanning tree algorithms now implemented by Cisco. But maybe Chapter 6 is the most useful. It explains how to secure a large campus network. Where an attacker can often easily gain physical access to the wired or wireless portions. Various attacks are mooted, Leading to effects like Denial of Service or, more insidiously, a Man In The Middle insertion. The book’s countermeasures include physically securing the switches and routers. Then, numerous software steps are available using Cisco firmware to detect rogue machines on a network segment. While “campus” is not restricted to a literal university campus, in practice the latter might indeed be a vast source of network weaknesses, given the diverse student population that has proximity and access to the network.

   Rating: 4 / 5
2. 

   Brandon Kim
   August 8th, 2010 - 01:43

   This is a review of Implementing Cisco Switched Networks (SWITCH) Foundation Learning Guide. Written by CCIE’s Richard Froom CCIE# 5102 and Erum Frahim CCIE# 7549 and Balaji Sivasubramanian.

   This is an excellent book on switching fundamentals. It clearly explains VLAN’s, how and where to use them. How the old 80/20 rule is now 20/80. Security topics regarding VLAN’s, DHCP snooping, port security, PVLAN’s and much more. The authors go deep into each topic and have a great way of explaining them while highlighting the important facts.

   You pick up little tidbits like ICMP redirects being turned off on HSRP enabled interfaces, or the maximum number of supported VLAN’s via ROAS (router on a stick) is 50, or that the number of SVI’s isn’t directly proportional to the number of VLAN’s supported on your switch. Who knew?

   These are the kinds of info that makes this book a gem, and I think going to be an extremely popular book. I have other switching books and they all seem to just go through the motions.

   I think switching and layer 2 in general are underrated. Layer 3 and routing always seems to get the limelight. But you need a properly working layer 2 for layer 3 to function. If this book isn’t on your bookshelf, get it!

   If you think you know everything about VLAN’s, or PVLAN’s or VACL’s, this book might teach you something new. There’s also a kindle version that’s about $5 cheaper than the hardcover.

   Although it’s written to follow the 642-813 format, this shouldn’t be passed over if you’re not studying for the certification.

   Brandon Kim
   
   [...]

   Rating: 5 / 5

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