Resource Library

Wi-Fi networks have been misunderstood by much of the IT community since their inception. Even the reasons for this misunderstanding are kind of hard to understand. The result has been that myths about 802.11 (better known as Wi-Fi) networks have grown almost as fast as the technology itself. In this web seminar, we'll examine 11 common Wi-Fi myths and explore ways to use correct information to make your networks scalable, secure and satisfying for your users.

In Routing Tables part one, we covered the basic purpose of a routing table and how an end device or intermediate device such as a router or multilayer switch can route based off its table. We also viewed different routing tables and how they are used to find a given...

In ACLs - Part 1 we learned the basics of access lists, including the facts that ACLs: Are created in global config mode End with an implicit “deny any” (which can be overridden) Must be placed into service somewhere to have any effect Thus, the commands: Rout...

The triple constraints model has been one of the main staples for teaching project management for as long as I can remember. The model is generally represented by a triangle with Scope on the horizontal leg, Time on the left leg, Cost or Resources on the right leg an...

Cisco Switches and Routers running the Internet Operating System (IOS) have many things in common. Configuring these devices of course, is a skill that is sharpened the more you touch the device. During this post, our discussion will primarily focus on the basic comm...

In my last post we discussed basic terminal access. The commands that I reviewed were for accessing the console port or vty lines of a Cisco router or switch. Network administrators should configure banners for legal and liability purposes. Now, we will see how to co...

Telepresence is a set of technologies that allow video conferencing in such a way that the user feels as if they are actually at the remote site. Cisco sells a variety of platforms in the telepresence space supporting up to three 65” high definition video displays,...

In our last blog series we discussed multiple access commands that can be configured on a router or a switch. These commands included cosmetic commands such as logging synchronous and exec-timeout that can be configured on the console port. We also discussed configur...

If you create presentations using the notes feature in PowerPoint, you probably have found yourself wanting to print multiple slides on one page (handouts) with the notes associated with those slides displayed on the same page. This layout can often help you better p...

Having discussed general ACL rules and syntax, let’s now turn to the differences between standard and extended ACLs. As you might recall, numbered ACLs fall into several ranges: 1 – 99: Standard IP 100 – 199: Extended IP 1300 - 1999: Standard IP (expanded rang...

As you may recall, we can use extended IP ACLs to filter packets based on source address, destination address, transport layer protocols, and other options, as follows: access-list 106 permit tcp host 1.2.3.4 host 5.6.7.8 eq telnet For a packet to be permitted by...

When we are addressing Voice over IP we need to remember that essentially we would like to reach customers over the PSTN or SS7 network. The only avenue to date to do this, is by using something called the telephone number. However, that number has undergone some cha...

When integrating a Voice over IP (VoIP) system into an existing network it is very important to have a good understanding of how much bandwidth is utilized for each call on the network. For most people, just starting out the bandwidth calculations can be a very daunt...

You may have noticed that it’s the dynamic routing protocols that get all the glory. Since I like rooting (routing?) for the underdog, let’s talk about static routes! As you may recall, a router has three methods for learning a route. A route can appear in the routi...

Recently we've been comparing using Telnet with Secure Shell protocol to allow remote access to a device such as a router or switch. Now, we're going to compare File Transfer Protocol (FTP) and Trivial File Transfer protocol (TFTP) for a Cisco router or switch. These...

RIP is a protocol that is used for routing IP networks. It was designed in the early 1980’s for communication between gateways (computers with two NIC’s). It is the oldest routing protocol used by the network industry and is considered by many to be inefficient or bo...

So far, in our discussion of Router Information Protocol (RIP), we’ve discussed the basics and also verified and reviewed RIP version1. We stated that RIP version 1 is a classful routing protocol that used FLSM and sent it routing updates without the subnet mask.  In...

Devices must send dual-tone-multi-frequency (DTMF) when a phone call is routed to an automated system. Automated attendant (AA), voicemail (VM), or interactive voice response (IVR) systems are some examples of the types of automated systems that can pick up phone calls.

Exchange 2010 builds upon the significant changes to the transport that were made in Exchange 2007. In this article, I'll review the transport pipeline and routing components and list some of the new architectural and administrative enhancements to the Exchange 2010...

Call Admission Control (CAC) is often times included as part of the same topic as Quality of Service (QoS), when in actuality CAC is a separate and complete topic itself. QoS is defined as traffic engineering on a packet switched network. This definition means movin...

Find out which OSI layer is concerned with reliable end-to-end delivery of data - and more. Get answers to your OSI reference model and network layer questions here.

When sending data end-to-end through a network, routers are used in internetworking to create a virtual network from one device to another, either locally or globally. Routers are configured to operate with most common network protocols. That means they know the form...

Cisco Unified Communications Manager (CUCM) includes a feature called "call throttling" that denies new call attempts when the system is in a state that may lead to delayed dial tone. The Real Time Monitoring Tool (RTMT) will generate a code yellow alert when call t...

No matter what book or manual you use to study for the CCNA examination, you will see various protocols and processes referencing an RFC. And, although frequently referenced, the RFCs are seldom actually included in the documentation. So, the logical question becomes...

In the previous discussion on QoS the Per-Hop Behaviors DiffServ uses to mark packets were identified. These where listed as:Expedited Forwarding (EF) – RFC 3246 – Provides a strict priority serviceAssured Forwarding (AF) – RFC 2597 – Provides a qualified delivery gu...

In the previous discussion on QoS, the uses of Per-Hop Behaviors DiffServ to mark packets were identified and discussed in detail. Today’s post will identify the mechanisms to implement QoS. The five main categories of tools used to implement QoS are as follows. Cl...

Cisco IP phones support a variety of different audio codecs. In this post, I will explain some of the differences and explain which versions of CUCM and the Cisco IP phones support the various audio codecs. Audio codecs are responsible for sampling human speech (a s...

ASA and PIX software version 7.0 introduced the configuration command nat-control which didn’t exist in previous versions of code. Although training course material for both the SNAF (Securing Networks with ASA Fundamentals) and SNAA (Securing Networks with ASA Advan...

Cisco Unified Communication H.323 and SIP gateways will require a dial plan on those gateways to extend calls to endpoints that may be configured. An endpoint may be either an analog or digital voice port that would provide connections to the public switch telephone...

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 aspect of Unified Communications is this concept of trunk groups.  I will discuss what they are, what benefit they can provide and how to configure them for Cisco gateways. First of all the official definition of a trunk group is “A group of trunks serving the s...

Last blog we looked at how we can use Trunk groups to ease the configuration of dial-peers and digit manipulation using analog FXO ports for an E911 solution. Now let’s take a look on how it can be used for T-1 CAS configurations and ISDN channel selection. The firs...

Project procurement activities are often managed by specialists. By this I mean that the procurement department takes over responsibility for purchasing and contract management from the project manager. As a result of this separation of responsibilities, the steps and stages of procurement are often poorly understood by PMs. In this and the next few blog submissions, I will attempt to shed light on procurement activities and relate these activities to the PMI PMBOK.

Internet Protocol (IP) routing protocols have one primary goal: to fill the IP routing table with the current best routes it can find. The goal is simple, but the process and options can be complicated. Routing protocols define various ways that routers chat among th...

In part 8 of this series we are going to unravel the mysteries of congestion management and its four main queuing methods.Congestion is the result of many factors and can occur in many places on the network. A few of the reasons for congestion are traffic aggregation...

In light of the recent tragic events in Haiti, it might be a good time to review some of the requirements for a well designed Uninterruptible Power Source (UPS) to be included in all of our critical network installations. As a CCNA, we are called upon to help maintai...

In part 8 of this blog series congestion management and its four main queuing methods were explored. This post will look at the first of four queuing methods: First In First Out (FIFO) queuing. To refresh our memories, congestion can occur anywhere within a network,...

Subnetting is a complicated topic that has confused students for a very long time. However, subnetting is an important topic for many different certifications with various vendors, including Cisco. In the real world environment, people are used to just punching in the numbers in many of the free subnet calculators that are readily available on the internet. For exam purposes, you still have to do this in a very fast manner since many exams are time-based and you don't have the luxury of spending those precious minutes on any single question. This Cisco training whitepaper will solve some of those age-old and complicated subnetting puzzles.

WFQ is a flow-based method that sends packets over the network and ensures packet transmission efficiency which is critical to the interactive traffic. This method automatically stabilizes network congestion between individual packet transmission flows.

I recently was presented with the challenge of logging ALL of the pertinent connection, disconnection, and termination messages associated with the Cisco SSL AnyConnect client without overwhelming the syslog capture display with extraneous messages. This blog will br...

Part 10 of this blog series looked at Weighted Fair Queuing, so now we move on to the next queue mechanism; Class Based Weighted Fair Queuing (CBWFQ).CBWFQ provides user defined traffic classes allowing for more control and functionality then weighted Fair Queuing. C...

Part 11 of this blog series looked at Class Based Weighted Fair Queuing. This blog will explore the next queue mechanism; Low Latency Queuing (LLQ). As seen in the previous section of this QoS series, CBWFQ provides user defined traffic classes allowing for more con...

Microsoft SQL Server has evolved over the years as a scalable, robust database management system and is now competing in the VLDB (Very Large Database) space with Oracle and IBM. The market share for the product continues to grow, based on total cost of ownership and ease of use. This white paper outlines some of the important fundamentals of Microsoft SQL Server 2008 that every DBA should know.

This report presents the results of a Canadian National survey, conducted by Global Knowledge in 2010. Its focus is on the future learning needs of business leaders. Four hundred twenty business leaders and managers responded to the survey, representing both corporate and government/public organizations as well as a wide range of industries and functional areas.  

The definition of cloud computing depends largely on whether you are a consumer or producer. The public cloud is geared more for the individual consumer or small company, while the private cloud is geared more for a medium-to-large company. In addition, the private cloud is branching out to incorporate the ability to have some data and applications serviced from the public cloud. This white paper examines the different types of cloud computing and shows what cloud computing can offer you.

The flexibility, reduced cost, and mobility of cloud computing have made the concept a hot topic. Before implementing this method of computing, however, it is important to consider the security of the "cloud." In this white paper, you will learn some of the risks and benefits of cloud computing to be sure it is the right solution for you.

Recently, I was asked the following question: “We plan to implement Windows 7 in our network very soon. We want to use Windows 2003 Domain Controllers for the next couple of years. Can we make the hundreds of new Group Policy setting available to Windows 7 Windows Server 2003 DCs?” This is not an unusual situation. Some organizations find they need to replace their desktop computers immediately because of age or obsolescence and others wish to upgrade to Windows 7 because of its superior security and performance. But there may be no budget or desire to upgrade to Windows 2008 or 2008 R2. Luckily, it is not difficult to adapt Server 2003 to work with Windows 7.

In my last post, we learned that the Dynamic Host Configuration Protocol (DHCP) is a computer networking protocol used by hosts, identified as DHCP clients, to retrieve IP address assignments and other configuration information. DHCP uses a client-server architectur...

There are many interesting new issues that seem to have come with the addition of voice and video to the data network. Most of the engineers that are now working on VoIP networks come from either a pure data network background or a traditional phone system background...

Learn how to calculate QOS Bandwidth Percent vs Bandwidth Remaining Percent using a Cisco-defined formula. Read on for answers and examples from the experts at Global Knowledge!

Windows 7 can be a good file server on very small workgroup networks. Although Windows 7 is limited to only 10 concurrent client connections as a file server it can do a good job making files accessible over a network. Windows 7 shares a great deal of code with Windo...

We have three major issues that we need to deal with in order to successfully use routers within a WAN provider’s cloud: Multiple routing tables in RAM Excessive latency Address-space collisions Let’s assume that we have a WAN provider with two customers, “A” an...

The flexibility, reduced cost, and mobility of cloud computing have made the concept a hot topic. Before implementing this method of computing, however, it is important to consider the security of the "cloud." During this webinar, we will help you understand some of the risks and benefits of cloud computing so you can decide if it is the right solution for you.

Even in professionally managed network environments it is still possible for mistakes to happen. If an Active Directory object such as a user or computer account is accidentally deleted  network access will be lost. Worker productivity will decline until the account...

The subject of this week’s post was actually prompted by a question from a former colleague.  Soon after the PIX Firewall added support for IPSec Virtual Private Networks, a command was added to the command-line, sysopt connection permit-ipsec. This command was subse...

Welcome back! Previously, we decided that in order for a Layer-3 MPLS VPN to function correctly, the ingress PE is going to need to push two labels onto each data packet. Let’s say that we have a data packet going from site A2 to site A3, using the topology shown in...

Private networks are under constant threat of attack, even when steps have been taken to "secure" them. The large volume of malicious codes, and their ability to evolve and adapt, requires security professionals and common computer/internet users alike to be mindful of their actions and constantly play defense. This white paper focuses on 10 common ways that malicious code can penetrate a network. Knowledge of these methods and the ability to recognize them are the first steps in preventing them from succeeding in harming your network.

Windows Vista introduced AERO, a desktop experience that had four major elements; Windows Flip, Windows Filmstrip, AERO Glass transparency and fully realized thumbnail views on the Taskbar. Windows 7 added several new features to AERO, including AERO Snap, AERO Shake...

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...

I recently came across an opportunity to use a relatively new feature in Cisco Unified Communications Manager (CUCM). Suppose you are the telecom administrator at a community hospital. During business hours, the Facilities Department is staffed and team members simpl...

Windows Software Update Services (WSUS) is commonly used to distribute security patches and updates for Windows operating systems and Microsoft applications. WSUS is a web application that runs within Internet Information Services (IIS) on Windows Server. When client...

Adding a new computer to an Active Directory domain can be a disruptive process, particularly if that computer is part of a large, high-speed deployment. Djoin.exe is a command line tool that permits the joining of a Windows 7 or Server 2008 R2 computer to Active Dir...

A feature common to IPSec Virtual Private Network implementations throughout the Cisco product line is Perfect Forward Secrecy (PFS). This optional additional component is now a default supplied configuration setting with the Adaptive Security Device Manager (ASDM) I...

As any network administrator will tell you, the ASA Security appliance (as well as its forerunner, the PIX) are capable of generating massive amounts of log messages, especially when the firewall/security appliance is set to log messages at debug level to the syslog...

As is sometimes the case, the idea for this article originated with a student question I received during one of the Securing Networks with ASA Fundamentals classes I have taught this summer. The course material mentions a simple scenario whereby IP Telephony traffic...

No matter which IT field you're working in, there are several skills that are useful for every IT professional to know. Here, seven experienced IT professionals working in the networking, programming, project management, and security fields, share what they believe a...

Ever seen a /32 prefix in the IP routing table? A /32 prefix is commonly referred to as a host route since it identifies a route to a specific IP host address. Since most (but not all) host computers don't run routing protocols, we could create a host route on a rou...

As is frequently the case these days, I get a brainstorm for an article during a Cisco Security training class I conduct. This summer I taught the Securing Networks with ASA Fundamentals class, which concentrates heavily on the Adaptive Security Device Manager (ASDM)...

When the hostname.domainname associated with my Small Office Home Office (SOHO) failed to update after a power outage, and a new DHCP-assigned external address was assigned to my router, I was reminded of the need for Dynamic DNS. This article will explore the implem...

Organizations can find significant value in adopting Agile methodologies and techniques. Agile practices can help ensure you meet customer expectations, deliver products on time, and create a motivated environment that is able to quickly adapt to change. This white paper explores 12 benefits of Agile development and management, explaining why you should consider incorporating Agile methodologies into your current standards and processes.

Need to know the difference between copper and optical fiber? Want to learn what the acronyms PBX, PC, PCI, PCIe, PCM, PDA, and PDU mean? Our "Geek Speak v3.0" can teach you all this and more. An update to our popular v2.0 "Geek Speak", this white paper will teach you more than 925 popular IT words, phrases, and acronyms.

Negotiation is a dialogue intended to resolve disputes, to produce an agreement on courses of action, to bargain for individual or collective advantage, or to craft outcomes to satisfy various interests. It is the primary method of alternative dispute resolution. This white paper focuses primarily on the negotiation process, different negotiation styles, and the various elements of communication that affect the outcome, including: Negotiation Communications, Constructive Questioning, Communication Obstacles (and overcoming those obstacles), Challenging Negotiation Situations and "Traps," and, finally, completing Successful Negotiations, a.k.a. "Getting to Yes"

“Traceroute” is a utility that’s commonly used when troubleshooting IP networks, but many network managers at the CCNA level and beyond aren’t really sure how it works or what you can do with it. One reason for this might be that, unlike most things in the IP world, there are no standards documents describing how “Traceroute” functions. Thus the implementations are vendor-specific, and not even the utilities’ names are standardized. With Cisco IOS and Unix, it’s called “traceroute”, in the Microsoft world, it’s “tracert”, and other operating systems have similar utilities, such as “tracepath” for Linux.

In this webinar, the first of two based on our Cybersecurity Foundations course, you will examine the following topics: verifying users and what they can access, ways a user can be validated to computer and network resources, how cryptography is used to protect data, symmetric and asymmetric encryption and hashes.

Interior Gateway Routing Protocol (IGRP) was a Cisco-proprietary Distance-Vector (D-V) classful routing protocol - basically an improved version of RIPv1. Like other D-V protocols, each IGRP router periodically flooded its routing table, but it differed from RIP in two ways. First, RIP’s advertisement interval was thirty seconds but IGRP’s was ninety seconds, which allowed IGRP to scale to larger networks than RIP. Second, RIP used a simple hop count metric, but IGRP’s more sophisticated metric was based on minimum path bandwidth and total path delay, with options to include link reliability and interface loading.

In this webinar, the second of two based on our Cybersecurity Foundations course, you'll build on what you learned in the first of the series, Protecting Your Network with Authentication and Cryptography.

One command that had a fairly long history first with the PIX Firewall and now the ASA is the shun command. In this post we’ll examine this command’s history, why it’s useful, and its new-found resurgence in threat detection implementation.

In this webinar, you will examine the need for IPv6 and whether it's possible to survive on IPv6 alone. You will learn ways to phase in IPv6 and how to successfully migrate to IPv6.

I attended a meeting this week with a customer of mine and a potential new vendor. The new vendor was there to pitch his configuration and setup service offerings for a specific ITSM toolset. My customer has already had one bad experience with an ITSM tool configuration vendor who promised one thing and delivered much less. He ended up with a tool that’s minimally used and not configured to match his business needs. He’s looking for a vendor that can understand his business needs and priorities and quickly help him get his tool configured and working in a short time frame. Then the topic of standard changes came up. My customer asked for examples of standard changes. The vendor responded, “Server reboots are an example of standard changes.”

Planning for a cyber disaster makes recovering from one much easier. Still, as important as disaster planning is, it's often overlooked or put off until it is too late. In this webinar, Global Knowledge instructor Debbie Dahlin discusses planning for the unexpected -- whether the unexpected means a simple power outage, a network security breach, or a major natural disaster. She'll discuss risk analysis and risk management techniques and explain the importance and process of creating a business continuity plan. Using a fictional company as an example, Debbie will walk you through the disaster planning process a security professional should use, and she will provide simple tricks to reduce your company's downtime before, during, and after a disaster.