Cisco IOS Commands – Using Extended Ping For Network Troubleshooting
The extended ping command is a very important part of any network engineer’s Cisco IOS commands knowledge, but you don’t find this being mentioned in many CCNA books. Many beginners do not know how to use this command effectively, but it is definitely a must-know and can isolate many network issues. In this post, I’ll go through some of the most important and useful parameters of this command:
Target IP address
The target IP address is the IP you want to send the ping/ICMP packet to. This is fairly straightforward, but one important note that if this IP is not routable from this router, you won’t be able to reach it, and will get no replies. The next step would be to do a traceroute to further isolate the issue.
Repeat count
Some physical line problems might only show up upon repeated ping tests. If it’s an intermittent issue, it’s best to put a larger number to simulate a stress test in order to ensure that there are no issues. For example, 1,000 or 10,000 packets might be a suitable number.
Datagram size
For stress test purposes, you can put a larger number in the datagram size to test for larger packets. It is not recommended to put a datagram size larger than the maximum MTU size of all the routers along the routing path as this would mean the packets would be fragmented (unless you are testing whether fragmentation is working properly). For an TCP/IP network running on ethernet, a good datagram size to use is 1500.
Some issues might also only show up with larger datagram sizes. These are usually related to some fragmentation issue along the way. It makes sense to test with larger datagram sizes as well as small ones in order to be sure.
Source address or interface
This part of the extended ping command is very useful to test whether it’s a routing issue or a switching issue. If you reach the directly connected router for a problematic host, and pings are successful when sourced from a directly connected interface (but not from another interface which is not directly connected), it usually indicates a routing configuration or process issue on that router, since no routing is needed for directly connected interfaces.
I hope you’ve found this post on Cisco IOS commands useful. Do subscribe to my RSS feed or follow me on twitter (@savvynetcert) for the latest updates.
Cheers,
Francis (SavvyNetCert.Com – @savvynetcert on Twitter)
Cisco IOS Commands – Using The Show Interface Cisco IOS Command For Troubleshooting Network Issues
Mastery of Cisco IOS commands is a very important part of the CCNA test and is also essential for anybody who is serious about a career in computer networks. Of all the commands, the most crucial are those you should have at the tips of your fingers when something goes wrong and you are suddenly called upon to troubleshoot. Every so often, the issue is related to a switchport and it is important to know how to use the show interface Cisco IOS command properly. If there is a network issue regarding slowness or disconnects, here are a 6 things you should be looking at when you check on the output of the “show interface” Cisco IOS command:
1. Is the physical port and line protocol up? If you don’t have layer 1 and layer 2 connectivity, there is no way any IP packet is going through this port.
2. Any duplex mismatch issues? Duplex mismatch could lead to slowness and errors in the network. If the speed does not match, the port won’t even come up.
3. Any QoS drops? If you have a QoS policy in place, it might be shaping and policing the traffic and dropping the packets. In this case, you might need to either rework your QoS policies, or advise the user about the high traffic levels.
4. What are the traffic levels, is this normal? You can check the input and output rates to see if this is normal for this time of day.
5. Any CRC or other input errors? Input and CRC errors could signify a physical problem with the port or cabling.
6. Any output errors or collisions? Output errors could also indicate a physical issue with the port or cabling. A full-duplex connection should have no collisions while it is quite normal for a half-duplex port to have collisions.
Cheers,
Francis (SavvyNetCert.Com)
P.S. Still preparing for your CCNA? Do get the right CCNA books – have you seen our CCNA book comparison chart?
CCNA Career Tips – 3 Areas To Focus On In Your New CCNA Job As A Networks Engineer
by abpalancajr on
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Developing strong technical skills and core network fundamentals are very important to your CCNA career. You need to review all the best CCNA books, however, if you want to improve your skills as a qualified CCNA networks engineer, here are 3 areas I suggest you focus on to become effective in your role in the quickest time possible:
1. Troubleshooting Skills
Troubleshooting skills are the bread and butter of any network engineer. As you progress you might be doing less and less troubleshooting and more deployment, but as a relative beginner it is the single most important skill you should develop as a good CCNA networks engineer.
This is even more evident evident from the newer Cisco exams, which have been structured to have more focus on debugging and fixing problems. Most of the entry-level jobs are support positions, where you will be identifying and fixing network issues reported by users about 80% of the time. It is thus important to become good at troubleshooting as soon as possible, so as to be effective.
2. Management of Expectations
Very often problems that arise cannot be easily solved quickly. Some problems which are more vague in nature like the network being slow or intermittent disconnections can be hard to track down and fix. More complex and mysterious issues might take from several days to several weeks to fix. It is important to manage the users’ expectations properly and keep them updated with an estimate of when the problem can be solved. If not, you might end up with a situation where they will call you every 10 minutes for an update. This is a very important part of your CCNA career so don’t overlook it.
3. Planning One Step Ahead
The computer network industry is constantly in a state of flux and it is important to be abreast of the latest developments. In the ideal situation, you should start training for tomorrow’s trends and technologies, however, this can be expensive and not all companies and corporations are willing to spend their training budget in this manner. At the very least you should keep yourself up to date with the current market direction to ensure that you do well in your CCNA career. For example, it’s likely that areas like cloud computing and media convergence will become increasingly important over the next few years and these are heavily dependent on network technology.
Hope this helps!
Cheers,
Francis (SavvyNetCert.Com)
P.S. If you’re still preparing for your CCNA exam, using CCNA video training packages are a great way to study. Do check out our comparison between the 2 best CCNA Video Training packages now. Click here to find out more!
Tips On Getting That First CCNA Job
by abpalancajr on
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Becoming a good CCNA network engineer and getting that first elusive CCNA job is definitely not an easy task, especially in this competitive job market. Here are 2 tips to help you succeed in your CCNA career journey.
1. Get the CCNA
Despite Cisco’s introduction of the CCENT certification (which you will get after passing the ICND1 exam), the CCNA is still widely regarded as the must have basic network certification by the industry as a whole. Thus, it is essential that you start working towards the CCNA certification as soon as possible. It has been shown in many surveys (including the TCPmag Salary Survey) that certified networking professionals are paid more. In this difficult market, being certified means that you have a better stab at that networking job. I previously made 2 introductory posts on the CCNA which you should review for more details on the CCNA journey – this usually starts by reading and studying the latest CCNA books. You might also want to take a look at CCNA video training which is an excellent way to get started.
2. Getting That First Networking CCNA Job
Once you have your CCNA, you can start looking for a suitable networking position. However, even if you haven’t gotten the certification yet, some employers might still be willing to employ you based on other factors. For example, if you are a CCENT certified and have relevant experience in other related fields such as servers, operating systems or general IT support, you might be considered favorably. Other networking certifications such as the CompTia Network+ certification (which is vendor independent) might also carry some weight.
One thing you might want to note is that the people who write the job specifications on career websites, job boards or newspapers might not be the same people who are hiring. Because of this, don’t always take the job requirements as set in stone and give it a shot anyway. It is common that the person that is eventually hired might not fulfill all the requirements as employers usually put too wide a range of certifications required in the ad.
An impressive and professionally written resume also helps with getting that CCNA job. You can do this yourself by reading some books or get a professional resume writer like those at ResumeWriters.Com (Tip: Use coupon code “newjob” at checkout for a 10% discount) for help. Using a professional to get your resume done can improve your chances of getting an interview significantly.
Let me know if you enjoyed this post! I can be contacted on twitter (@savvynetcert) or using the feedback form above.
Cheers,
Francis
P.S. If you are using a professional resume writer to get your resume done (recommended), don’t forget to claim your 10% discount at ResumeWriters.Com by using the coupon code “newjob” at checkout.
CCNA Video Training – 2 Best CCNA Video Training Products Compared
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The 2 most popular ways to study for the CCNA traditionally have been to use CCNA preparation books or to attend a formal class – whether attending an official CCNA academy class or training via one of Cisco’s authorized training partners. Using CCNA books to study is still an excellent choice – see our quick CCNA book comparison chart here if you are still unsure of what to buy. However, if you very much prefer CCNA video training, there are high quality materials available now.
Using video to study for the CCNA essentially gives you all the benefits of studying for the CCNA in a classroom setting but you are able to do so at your own pace. Suppose you can only attend “class” once a week, and only at night after work – with CCNA video training, this is not a problem. If you need to repeat a class, you can simply watch the video again. It’s like having a fully qualified instructor with you all the time, and you can repeat the class as often as you would like. All this, with the added advantage that CCNA video training costs just a fraction of what a classroom based course would cost.
There are 2 CCNA video training courses which are well established in the market today. They are the CBT Nuggets Cisco CCNA Certification Package and the TrainSignal Cisco CCNA training.
The CBT Nuggets video training covers all the essential topics in the CCNA exam, and includes 59 videos totaling 27 hours of training. It is taught by Jeremy Cioara, a CCIE certified instructor. 2 CCNA practice tests are also available for $69 each. The video training costs $399.
The TrainSignal Cisco CCNA training also covers all the topics of the CCNA exam, and includes 29 hours of video training. It is taught by Chris Bryant, a well known CCIE certified instructor. In addition, the TrainSignal training boasts and impressive array of training materials over and above the video training, This includes iPod videos, mp3 audios and accompanying instructor notes. In addition, the TrainSignal CCNA package also includes accompanying PDF instructor notes which you can print out. On top of this, the package includes a full version of the Cisco CCNA practice exams by Transcender, which is a well known award winning practice exam. This comprehensive package is available from TrainSignal for $397 (cheaper than the CBT Nuggets solution).
Comparing the 2 products, I would definitely recommend the TrainSignal Cisco CCNA video training. They have a free CCNA training sample video over at their site so you can take a look at the quality of the video and they stand by their product with a 90 day satisfaction guarantee. Do check out the free CCNA training sample video and see for yourself.
If you use twitter, you would be happy to know that @TrainSignal is very active on twitter and always willing to help – you can’t beat that for support!
For a quick comparison, please see the below chart:
TrainSignal CCNA Video Training(Recommended) | CBT Nuggets CCNA Video Training | |
|---|---|---|
| Covers all CCNA topics |  | |
| Run Length | 29 Hours | 27 Hours |
| Trainer | Chris Bryant, CCIE | Jeremy Cioara, CCIE |
| High Resolution Video | | |
| iPod Video | |  |
| MP3 Audio | | |
| Instructor Notes | | |
| Practice Exam | Transcender Award-Winning CCNA Practice Test | Extra at $69 each. |
| Guarantee | 90 Day Complete Satisfaction Guarantee | Guarantee against media damage |
| Price | $397 | $399 |
| Buy Now! |  |  |
I’m not too sure how long the TrainSignal $397 price will last as this is a limited-time discount from their usual price of $799.
Click here to get your copy of the TrainSignal CCNA Training Video series – with a 90 day total experience guarantee!
