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Networking blog roundup: Cisco NAM; why BGP matters in an SDN world

In this week's networking blog roundup, bloggers consider the significance of the new Cisco NAM and troubleshoot high CPU usage in an ASA firewall.

FCC spectrum policy promises greater Wi-Fi capacity

The ever-increasing appetite for Wi-Fi has pushed the Federal Communications Commission to consider policy that would make more spectrum for Wi-Fi available, giving users more capacity. The commission's proposition aims to give unlicensed devices access to spectrum in the 5 GHz bands, allowing for transmissions speeds up to 100 times faster than the Internet connection in the typical American household, according to The New York Times.

Last week, Revolution Wi-Fi blogger Andrew vonNagy took a look at what the FCC's actions could mean for Wi-Fi networks. He explained how many channels would become available and how practical the use of the channel widths would be for enterprises.

Take a look at vonNagy's piece for a summary of the FCC proposition's potential effects, as well as a recap of the developments in U.S. spectrum policy throughout the past year.

SDN is firmly rooted, but BGP still matters!

Software-defined networking (SDN) is not a new concept, according to Juniper Networks' Truman Boyes. Engineers have long been using software to go beyond the functionality of their protocols. On his blog, the Loopback Filter, Boyes made the case that even in a world of OpenFlow, Quantum plug-ins and new Linux Kernel Modules, tools like the Multiprotocol Border Gateway Protocol (MP-BGP), route reflectors and route targets still matter. Creating new models of connectivity may be exciting, but developers shouldn't lose sight of an underlying simplicity, achievable through authoritative sources such as the forwarding and routing information bases.

Read Boyes' post on the relevance of traditional protocols to learn about taking advantage of these more clearly defined tools.

New Cisco NAM clears the path for future service models

The Network Analysis Module (NAM) Cisco announced last month is currently the only service module on the market for the Nexus 7000 series switches, but network engineer John Herbert thinks the Cisco NAM will blaze a trail for many modules to come. Herbert took a look at the NAM, detailing its capabilities and the context of the features relative to previous service modules. NAMs may take away space from actual network ports, but their straightforward functionality in capturing traffic makes them a compelling tool that will likely continue to appear, particularly as the technology progresses with innovations like the new virtual NAM.

Visit Herbert's blog Lame Journal to get the scoop on what Cisco's release might mean for the service module market.

Troubleshooting high CPU usage in Cisco ASA firewall

When an unexpected flare-up in CPU usage caught the eye of networking practitioner Ethan Banks by accident, he combed through the system to investigate. What he found -- and didn't find -- speaks to an opacity in Cisco Adaptive Security Appliance (ASA) packet flow information and highlights the overall importance of maintaining logs, alerts and controls in a network.

Unexpectedly high CPU usage on a Cisco ASA firewall, originating in the traffic-monitoring dispatch unit, failed to register on the network management system (NMS). A dump of the firewall logs revealed that a deluge of advertising-related lookups hitting the domain name system servers was part of the problem, but despite Banks' Googling efforts, the specifics remained fuzzy. Shutting down the switchport ultimately returned the CPU to normal -- an important baseline to know, Banks noted. Keeping logs of activity to establish a standard of comparison will make it easier to get a grasp of abnormalities, which customized NMS alerts can catch.

Walk through Banks' troubleshooting process in his post on Packet Pushers.

Differentiating WAN circuit topologies: An illustrated guide

With half a dozen circuit types available for connecting sites across a WAN, keeping the options straight isn't always easy. Jeremy Stretch of makes the task more manageable with an outline of the possibilities, incorporating simple graphics and brief explanations of the various topologies.

Check out the breakdown for clarification on potential circuits, from the basic point-to-point to the dynamic Multiprotocol Label Switching VPN.

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