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In this post I’ll focus on a topic that’s mentioned in the Cisco FIREWALL training class but isn’t emphasized there or in the online Cisco ASA documentation. When configuring failover on a pair of ASA security appliances, a situation can arise in which network disruption occurs due to the secondary ASA in a failover pair becoming active first and then the primary comes online second. Both the documentation and the courseware point out that this causes the secondary (and active ASA) to swap its interface MAC addresses with those of the primary. Being naturally skeptical about this behavior, I decided to investigate. The rest of this post illustrates my confirmation of this phenomenon.

The official Cisco CCNP Security FIREWALL training course (as well as other documentation) recommends enabling the inspection of the Internet Control Message Protocol (ICMP), even though it’s disabled by default. The image below displays the recommended practice as configured in ASDM, but the curious student might wonder what the unchecked “ICMP Error” box is. That’s what I’ll focus on in this post.

The Cisco UCS is truly a “unified” architecture that integrates three major datacenter technologies into a single, coherent system: Computing Network Storage Instead of being simply the next generation of blade servers, the Cisco UCS is an innova­tive architecture designed from scratch to be highly scalable, efficient, and powerful with one-third less infrastructure than traditional blade servers.

Previously, I talked about the logical and physical steps to building a basic certification lab, concentrating mostly on the CCENT/CCNA Routing and Switching level. Once you have that set of certifications under your belt, there are several options for specialization. Each of these advanced technology tracks serve as methods of enhancing your professional skill set as follows:

Anyone who’s managed switches over the years knows that the Spanning-tree protocol (STP) is both the best and worst thing to ever happen to the data center at layer 2 of the OSI model. On the plus side, the Spanning-tree protocol is what first allowed us to create redundant paths within our switching infrastructure, making our data center much more resilient to outages than ever before. Anyone who’s experienced a “broadcast storm” knows the full value of Spanning-tree in the traditional switching environment. We’ve also seen many improvements in Spanning-tree over the years to make it work faster and more efficiently (i.e. Rapid Spanning-tree, Bridge Assurance, and many others).

Configuring a wireless lab for study and testing capabilities is a bit more involved than you might think at first glance. Most of the requirements take place on the management devices, but the underlying switch infrastructure requires some preparations as well. The tasks involved are as follows:

Global Knowledge Course Director and Lab Topology Architect Joey DeWiele, a specialist in Unified Communications, explains QoS.

In the previous post, we discussed the need for VXLAN in the cloud along with the issues it solves. In this post, we will focus more on how VXLAN works.

Both technologies, Ethernet and FC, satisfied the two conditions at that time, but there was a catch. Read more. 

This week we'll review the IPv4 Address Classes including subnet masks, examples of Class C, Class B, and Class A subnet masks, and planning IPv4 addresses.

Global Knowledge Course Director and Lab Topology Architect Joey DeWiele, a specialist in Unified Communications, explains the difference between Cisco's Call Manager Express & Call Manager.

The most obvious difference 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. Hubs are really just multi-port repeaters. They ignore the content of an Ethernet frame and simply resend every frame they receive out every interface on the hub. The challenge is that the Ethernet frames will show up at every device attached to a hub instead of just the intended destination (a security gap), and inbound frames often collide with outbound frames (a performance issue).

As we discussed previously, Cisco created the Nexus Operating System (NX-OS) to power its next-generation data-center switching platform. While this new OS shares many similarities to the original IOS, there are some definite differences that you need to be aware of as you begin using it.

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.

This is another topic of heated debate, and it changes from network to network, but I found a simple approach that works in most cases. Since I have four queues and four classes of traffic, I need to categorize my important traffic into four classes. Strictly for explanation purposes I took some liberty in defining four categories of traffic that are very effective in both large and small networks. These classes are: Real Time Protocol (RTP), Network Management (NetMgt), Business Critical, and the Default.

Rodger Foster, our senior Cisco instructor, reviews how multiple gateways are used to provide redundancy in the network.

Course director Jim Thomas explains how our custom labs, which utilize external hosts, ISR routers, and DMZ, provide a real-world environment for students.

A video covering our Cisco Unified Communications courses - ACUCW1 & ACUCW2 - by Global Knowledge Course Director and Lab Topology Architect Joey DeWiele, a specialist in Unified Communications.

Global Knowledge Course Director and Lab Topology Architect Joey DeWiele, a specialist in Unified Communications, discusses Cisco Unity, Unity Connection & Unity Express.

Diane Teare, Global Knowledge's Cisco Course Director, discusses the advantages to taking our CCNA Boot Camp.

Global Knowledge Course Director and Lab Topology Architect Joey DeWiele, a specialist in Unified Communications, explains presence.

Meet Global Knowledge course director and lab topology architect Joey DeWiele, a specialist in Unified Communications. Joey will walk you through the benefits of our exclusive Cisco UC lab architecture - a more scalable and stable approach to the all-important labs featured in unified communications courses. Our labs feature upgraded hardware and software including Custom Lenovo T61 PCs, 7965 IP Phones, 3560 Switches and Call Manager 7. With our flexible UC architecture, students are able to view and experience the full lab architecture regardless of which Cisco UC course they are taking or the skill set they are seeking. The lab architecture features a realistic network with redundant environments that are made rich with multiple machines, pre-deployed tools with shortcuts, online documentation that is particular to individual pods, and multiple OS support for all virtual machines (Windows, Linux, VMware).

Global Knowledge instructor Doug Notini discusses the benefits of our FIREWALL 2.0 - Deploying Cisco ASA Firewall Solutions course.

In this video, you will learn about the High Availability options in SQL Server 2008: Server Clustering, Database Mirroring, Log Shipping and Peer-to-Peer Replication.

In this video, you will learn how to a use a new feature of SQL Server 2008 called Transparent Data Encryption for enhanced security.

John Barnes, Global Knowledge's Cisco Course Developer, discusses enhancements to our UCS Troubleshooting Boot Camp and suggestions for students in preparation for this course.

In numerous Cisco classes, students learn about IPv4 and IPv6 address subnetting, complex subnetting, variable length subnet masking (VLSM), summarization, prefix routing, and address aggregation. These are valuable skills. In order to apply these skills efficiently, a network designer should possess one additional skill. Planning the IP address space for a Class A or B IPv4 address is necessary to apply the complex skills listed above properly. Complex subnetting, VLSM, and IP address summarization can be implemented simply and efficiently with proper planning.

Instructor John Harmon continues his explanation of subnetting by showing how subnet masks can be used to sub-divide networks.

Instructor John Harmon explains subnetting using binary numbers and decimal conversions.

Frequently, questions come up in the Cisco Contact Center Express classes I teach concerning the ability of the system to perform this or that task. In this blog post, I will cover some of the more popular questions I get during class.

Need to control the digits contained in the telephone number that enter or leave a gateway? Digit manipulation involves adding, subtracting, and changing telephone numbers. You can manipulate calling numbers, called numbers, and redirecting numbers, as well as the numbering plan and ISDN number type. Learn about the techniques that are applied to incoming or outgoing calls, or globally to all calls. You can also manipulate telephone numbers before or after a dial peer is matched.

In this report, I've reviewed the 15 most popular certifications according to our more than 12,000 North American respondents to our annual IT Skills and Salary Survey. For each certification, you'll find a brief description, the average salary, and some insight into why it is popular.

You know you need to invest in training, but how do you get the best return on investment (ROI) from your training dollars? To help you make smart training decisions, we've put together this guide, which illustrates some alternative and little-known payment options, the types of discounts and promotions available with training and a suggested list of courses that give you excellent value.

Your Microsoft SQL Server database often contains the most valuable information in your organization. Get tips for securing it properly and effectively in this free, information-packed webinar with Microsoft SQL Server expert Gidget Pryor. In just an hour, Gidget will demonstrate the layered security approach used by SQL Server. She will step you through the process and best practices of setting up logins, users, roles, schemas, and permissions, and she will review the security model changes that have taken place from SQL Server 2005 through SQL Server 2012. She will also review SQL Server 2012 training and certifications.

Instructor Carol Kavalla talks about the advantages of taking a Cisco Data Center Unified Fabric Implementation class from Global Knowledge.

The short answer (and a common one in our industry): it depends. When comparing Cisco IOS with Juniper Junos, the decision to choose one over the other is difficult and often boils down to cost. Of course, there are other factors to consider.

With the advent of video use in our everyday communications, a number of questions commonly surface. One of them is the question of terminology. What's the difference between video conferencing and telepresence? What is meant by immersive technologies? Frankly, there is no one single right answer.

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?

If you’re in IT, you’ve likely heard the saying, “In technology, the only thing constant is change itself,” and boy is that right! For technical companies, if you are not moving forward, then you’re falling behind. There is no such thing as standing still! A perfect example of this mindset is in Cisco’s evolution of video conferencing and telepresence.

Join Microsoft SQL Server expert Brian Egler for an hour-long webinar covering the key features and updates in the upcoming release of Microsoft SQL Server 2014! You will get a thorough review, along with demonstrations, of how SQL Server 2014 provides substantial improvements in performance, manageability, and availability that will make your job easier.