Cisco CCNA / CCNP Certification Exam: Caller ID Screening

Cisco CCNA / CCNP Certification Exam: Caller ID Screening And Callback

As a CCNA and/or CCNP candidate, you’ve got to be able to spot situations where Cisco router features can save your client money and time. For example, if a spoke router is calling a hub router and the toll charges at the spoke site are higher than that of the hub router, having the hub router hang up initially and then call the spoke router back can save the client money (and make you look good!)

A popular method of doing this is using PPP callback, but as we all know, it’s a good idea to know more than one way to do things in Cisco World! A lesser-known but still effective method of callback is Caller ID Screening & Callback. Before we look at the callback feature, though, we need to know what Caller ID Screening is in the first place!

This feature is often referred to simply as “Caller ID”, which can be a little misleading if you’ve never seen this service in operation before. To most of us, Caller ID is a phone service that displays the source phone number of an incoming call. Caller ID Screening has a different meaning, though. Caller ID Screening on a Cisco router is really another kind of password – it defines the phone numbers that are allowed to call the router.

The list of acceptable source phone numbers is created with the isdn caller command. Luckily for us, this command allows the use of x to specify a wildcard number. The command isdn caller 555xxxx results in calls being accepted from any 7-digit phone number beginning with 555, and rejected in all other cases. We’ll configure R2 to do just that and then send a ping from R1 to R2. To see the results of the Caller ID Screening, debug dialer will be run on R1 before sending the ping. Ive edited this output, since the output you see here will be repeated fire times once for each ping packet.

R2(config-if)#isdn caller 555xxxx

R1#debug dialer

Dial on demand events debugging is on


Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:

03:30:25: BR0 DDR: Dialing cause ip (s=, d=

03:30:25: BR0 DDR: Attempting to dial 8358662.

Success rate is 0 percent (0/5)

R1 doesn’t give us any hints as to what the problem is, but we can see that the pings definitely aren’t going through. On R2, show dialer displays the number of screened calls.

R2#show dialer

BRI0 – dialer type = ISDN

Dial String Successes Failures Last DNIS Last status

8358661 1 0 00:03:16 successful

7 incoming call(s) have been screened.

0 incoming call(s) rejected for callback.

The callback option mentioned in the last line shown above enables the router to reject a phone call, and then call that router back seconds later.

R2 will now be configured to initially hang up on R1, and then call R1 back.

R2(config-if)#isdn caller 8358661 callback

R1 will now ping R2. The pings aren’t returned, but seconds later R2 calls R1 back.


Success rate is 0 percent (0/5)


03:48:12: BRI0: wait for isdn carrier timeout, call id=0x8023


03:48:18: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up


03:48:18: BR0:1 DDR: dialer protocol up


03:48:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0:1, changed state to up


03:48:24: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to 8358662 R2

show dialer on R2 shows the reason for the call to R1 is a callback return call.

R2#show dialer

BRI0 – dialer type = ISDN

Dial String Successes Failures Last DNIS Last status

8358661 3 0 00:00:48 successful

7 incoming call(s) have been screened.

10 incoming call(s) rejected for callback.

BRI0:1 – dialer type = ISDN

Idle timer (120 secs), Fast idle timer (20 secs)

Wait for carrier (30 secs), Re-enable (15 secs)

Dialer state is data link layer up

Dial reason: Callback return call

Time until disconnect 71 secs

Connected to 8358661 (R1)

The drawback to Caller ID Callback is that not all telco switches support it, so if you have the choice between this and PPP Callback, you’re probably better off with PPP Callback. However, it’s always a good idea to know more than one way to get things done with Cisco!

Helpful Tips For Online Marketing Success

A business is an opportunity which is used to attract customers and develop potential clients to expand your customer base. E-commerce is a trend that is skyrocketing, so growing your customer base online is increasingly becoming more and more important. Mentioned below are a few tips for online marketing success:

Understand Your Customers

Before marketing any product or service online, you need to first understand your target market’s decision chain. This will help you in discovering what is important to them, after which, you can make the right offer. After you do this, you should focus your efforts on educating them about the value they will get from the product or service.

Create and Develop an Online Presence

You then need to establish your online business presence so that customers can easily find you. This is possible with search engine optimization (SEO), YouTube marketing and Google ads. The more outstretched your presence is online, the more easily accessible you will be to customers.

Use keyword rich content so that your website can pop up on the first page of searches conducted by customers. With a high search engine ranking, you will experience a growth in the number of visitors that come to your website. This way more and more customers will grow aware of you and your business, enhancing its success with an increase in sales.

Use Social Media to Connect With Customers

Social media is a highly influential platform. Start developing the presence of your business on networking sites such as LinkedIn, Facebook, Google+, and Twitter. Create business pages so that you can hold discussions, share updates and promotions, and gradually build stronger connections with your target audience and potential customers.

Upon building connections and communicating with your target market, you can gain precious customers’ insight which can be helpful in understanding them better, growing your business presence, and attracting new customers.

Marketing Materials Should Promote Your Presence Online

You should ensure that your business cards, letterheads and other print media publications promote your online business presence by displaying your website address. You can also promote your website via communication channels such as television commercials and radio. Lastly, the address of your website can also be added to your phone message and in every employee’s email signature. It will not be long before customer prospects start visiting your website.

Power up Your Customer Support Services

When customers receive assistance and support facilities instantly, they start trusting your business to cater to their every need. When this happens, they start becoming more loyal. Customers like getting feedback on a quick basis and when doing so, put in a quick reminder of any discounts or incentives that are being offered by your business.

The internet has a vast scope of opportunities for the growth and development of various kinds of businesses. With the help of the marketing tips mentioned above, you can be sure that your business is headed towards the direction of online marketing success.

Advantages Of Travertine Flooring To Add Value To Your Home

Advantages Of Travertine Flooring To Add Value To Your Home

If you are looking to add great value to your home then considering travertine tiles to add that spice of elegance and beauty. Travertine floors are made from the majestic natural stone and offer incredible depth and colour, adding a great aesthetic appearl to your home. Travertine flooring has its advantages and limitations. Understanding your lifestyle, needs and preferences is key to ensuring that the function of this flooring option is fully maximized for your home.

So what exactly is travertine?

Travertine flooring is made from travertine, a type of limestone that forms through mineral deposits, particularly in and around hot springs. Travertine limestone is composed of calcium carbonate, the same material that makes stalactites and stalagmites.

Travertine tiles have been used for many years not just for its durability but also for its looks and texture. The Romans, for example, built many of their famous buildings using travertine. A notable example is the Colosseum, a building made mostly from the material and has remained as one of the most enduring landmarks in Italy. It is also commonly found in some of the world’s oldest buildings.

So what are the advantages of travertine flooring?

Travertine flooring is quite durable and with sufficient care, it can last for many years and maintain its beauty. When sold, the material is usually displayed with a mark indicating its hardness on the MOH scale. In general, travertine registers at the MOH scale with a 3-4 rating, which is near or equivalent to that of marble. As long as it is sealed, treated and cared for, it can withstand regular foot traffic plus lots more.

If your flooring is not sealed and installed in its rough form, it offers excellent traction. This is why a travertine paver is safer to use than ceramic tiles outdoors in the garden or patio. Travertine also comes in several colours such as beige, white or ivory, brown, red and gold so tiles can be matched to a preferred colour scheme. It is also processed and sold in different finishes such as chiselled, brushed, tumbled and honed.

What are the disadvantages of travertine flooring?

Travertine flooring is made out of natural limestone. If it is unsealed, it can be damaged or stained by high-acid products because it is by nature porous. Travertine is alkaline and will react when it comes in contact with acids from liquids and foods. It can also be damaged over time due to corrosion if cleaned using acid-based products. It also tends to be rather slippery when wet, especially if it is polished.

This type of flooring is also a high-end construction material and as such, tends to be priced at a premium. It is possible it can be as expensive as granite tiles or even more. Travertine flooring also behaves similarly to other natural stone materials in that it can chip or break and is vulnerable to scratching. It also tends to be quite heavy, particularly the larger 12″x12″ tile units, which can weight as much as 2.5kgs.

Travertine flooring also requires regular care and maintenance and may not be the best option in homes where there are kids and/or pets if it is unsealed. Very often you’ll find that it is used more often in the patio and living room areas and occassionally in the kitchen or bathroom.

Hot Tips About Dual Core Processors

Dual core processors have become very popular in the world of computing. Some hot tips about dual core processors have been printed in many computer magazines for the last few years and have served to whet the appetite of many computer users looking to upgrade their computer systems. The ability of dual core processors to make computer systems run much faster and cooler means that many people want these processors in their computers.

The hot tips about dual core processors have been talked about in many computer user forums online for many months now and the consensus seems to be that everyone wants them to be in their computer systems. While many older computers may not have the correct architecture to accept these dual processors, many of the newer models of computer can easily adapt to this innovation. The ability of dual core processors to handle multiple programs at one time is a very attractive aspect for anyone thinking of buying dual core processor architecture for their computer system.

The goal of the companies that are producing these dual core processor systems has been to get a system that can do the work at the best price for consumers. Because hot tips about dual core processors have become commonplace among many computer users, the popularity of these processors has grown a lot. Many people have been waiting for the bugs to be worked out of the dual core processor systems, before they purchase a system for their own computer.

The main groups of computer users who are interested in this technology are the ones that use higher memory applications and people who use a lot of graphic programs such as computer games. This last set of users has been behind the dual core technology since the beginning as this innovation will enhance their playing considerably and allow their systems to compete with video game consoles already on the market. Once dual core processor systems can easily compete with video gaming consoles, and then the gaming consumer will think twice about buying a video console rather than upgrading to a dual core system.

While some manufacturers of these processors have gone after the gaming market, others have aimed their marketing towards the business sector. Offering reliable and powerful processing systems to both markets has resulted in many computer users having much more powerful systems with a high level of reliability. The speed at which these processors deliver results is staggering to many users who have been waiting for innovations such as this to come along. Many hot tips about dual core processors can be traced back to online forums among users who wanted a better and faster way to process computer applications.

The companies that create these applications wanted the manufacturers of the processors to make the processors faster so that the newer programs could be run much better and faster than they once had. This allowed for a great deal of innovation in the programs being produced as well. Knowing that the dual core processors could handle the program criteria allowed the programmers of games and applications to do whatever they wanted in the creation of a better and faster game or applications program.

When talking about hot tips about dual core processors, its important to realize that not only are these new processors faster at handling multiple tasks, but they are more capable of being able to deal with many computer programs and processes running at the same time. Since many people seldom run a single program or application on their computer at any one time, this ability to handle multiple applications is very important. The chance of your computer crashing under the load of trying to operate many programs at the same time is very slim now. These powerhouse processors can easily handle all the computing needs you have. You can read all about the newest innovations where dual core processors are concerned by simply searching online for manufacturers who specialize in these systems for computer users.