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...