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Learn about the five types of area networks.

Now that the network is installed, each switch has a bridge ID number, and the root switch has been elected, the next step is for each switch to perform a calculation to determine the best link to the root switch. Each switch will do this by comparing the path cost for each link based on the speed. For paths that go through one or more other switches, the link costs are added. The switch compares this aggregate value to the other link costs to determine the best path to the root switch.

That depends on their configurations. For example: While it makes very good sense to include redundant physical links in a network, connecting switches in loops, without taking the appropriate measures, will cause havoc on a network. Without the correct measures, a switch floods broadcast frames out all of its ports, causing serious problems for the network devices. The main problem is a broadcast storm where broadcast frames are flooded through every switch until all available bandwidth is used and all network devices have more inbound frames than they can process.

According to Cisco marketing, Dynamic Multipoint VPN (DMVPN) “will lower capital and operation expenses, simplifies branch communications, reduces deployment complexity, and improves business resiliency.” Okay. But what is it, really, and why should we care?

The key difference between hubs, switches and bridges is that hubs operate at Layer 1 of the OSI model, while bridges and switches work with MAC addresses at Layer 2 of the OSI model.

Software-defined networking (SDN) is a solution that will enable your organization to meet the demands of network programmability and automation. The result will be greater network agility to support new applications while complying with increasing security needs.

There are some common misconceptions on the part of some of my students as to how VPN sessions are established from either a remote location or remote user to the ASA firewall. In particular, a “gray area” seems to be when the attributes from the tunnel group are app...

One of the many useful features of tunneling is to carry non-IP traffic across an IP network, and this is still the case when dealing with IPv6 traffic. This transition mechanism makes use of a configured tunnel to transport IPv6 over a native IPv4 network, which may consist of two sites or more. Unlike the previous transition mechanisms, tunneling is not monolithic; while the basic principles may be similar, the operations are different. The following chart gives a breakdown of the current, major tunneling types in use, particularly in a Cisco environment:

While the last few years have brought about many great advances in IT and network technology security and risk management have a critical point. There is a host of new concerns the IT security manager must be concerned with, including social networking, mobile, cloud, and information sharing. This has unleashed a new wave of change and potential risk. Risk management is required to deal with these emerging technologies and should provide the rationale for all information security activities within the organization. You can think of risk management as the process of ensuring that the impact of threats and exploited vulnerabilities is within acceptable limits at an acceptable cost. Risk management requires the use of countermeasures. Countermeasures can include any process that serves to reduce threats or vulnerabilities.

Occasionally as I'm teaching a Cisco training class, I get an idea for a blog post and it happened again this week. The Securing Networks with ASA Fundamentals curriculum is mostly based on the Adaptive Security Device Manager (ASDM). While the class describes the us...