Wednesday, August 8, 2012

Linksys wireless router config for bridge mode

This is a follow up to my previous post WiFi Router Problems - How to Improve home wireless connection .

In it I will describe how to setup a Linksys E2500 wireless router to provide 5GHZ options to wifi routers that don't support this option (like the Verizon FiOS router (Actiontec MI424WR) .

Don't plug it right away to your existing router since it will probably conflict with it, instead connect it to the power and let is load.

After about 4-5 minutes, the router should be up and running and you should plug your computer's network cable to one of the wired ports. We are going to make changed on the wireless and therefor need to be connected with a network cable, otherwise our link would drop.

Once connected, you should get an IP address from the router and the default gateway would be the linksys, you can use ipconfig to figure out the default gateway address.

Open a web browser and point it to the address, a login prompt should appear and the default credentials would be username: admin with blank password.

Once logged in you want to do the following things:

  1. Configure the E2500 to act as a wireless bridge (aka access point mode).

  2. Configure an IP address to the router that does not conflict with your existing wifi router.
  3. Disable the 2.4 GHZ service on the Linksys, we are going to use it for 5GHZ only.
  4. Define the 5GHZ wireless parameters and security.
  5. Define a password for the admin account.
  6. Once those steps are completed, you can connect your E2500 to the provider router (FiOS) and start using the 5GHZ SSID.

Here are some relevant screen shots for the various steps, fields that are highlighted in yellow should be configured:

This image is for the ip address config and the Bridge mode.

You should probably name the 5 GHZ SSID with a name that has 5 at the end, so it's easy to identify.

Wireless security is very important, use WPA2 and set a long passphrase with letters and numbers.

Finally, don't forget to change you admin password, otherwise you can be hacked in no time.

thats it, save, plug to the provider router using a network cable and you should have the 5GHZ SSID available to you.

Wednesday, July 4, 2012

WiFi Router Problems - How to Improve home wireless connection

If you live in a densely populated area, where many of your neighbors use WiFi, and your connection keeps dropping, or it is intermittent and unstable, there is a solution for you.

The issues that this post will address are related to wireless (or WiFi) instability, frequent disconnects, network issues which are mainly affecting iPad and are bringing the "no internet connection" error message.

Wireless or WiFi is a communication protocol that is defined under a standard called 802.11 , this standard is using two main frequencies to transmit over the air, 2.4 GHz and 5 GHz.

Under the sub standard called 802.11g, which is the most common protocol in residential networks these days, the transmission is being done using the 2.4GHZ method. The problem is that this frequency only allow 11 channels for the entire spectrum and only three usable (non overlapping).

In short, a WiFi user can only use channels 1, 6 or 11 in the United States, based on the current standards. As long as there are only three wireless routers around, that's not a problem, since every router can use one of the channels and no conflict will be happening. 
If there are more than three routers around, channels need to be shared and in a high share environment, devices will disconnect from the router.

How can you tell if this is the reason to your disconnects, check how many available wireless networks are showing up when you enter the network settings and if you see more than five, there is a good chance that this is your problem.

Here is a snip of what I see in my windows 7 wireless network connections window (network names were deleted for privacy):

This exact thing was happening to me and was mostly experienced while using the ipad, where the ipad would constantly disconnect from the network and display the 'choose a network' dialog.

What can you do? there is a solution for that, use a wireless protocol that operates in the 5 GHz frequency. Why would it matter? because 5 GHz  gives you twenty more channels to use (total of twenty three) and reduces the potential channel clogging that happens in the 2.4 GHz spectrum. The wireless protocol that can be used to take advantage of this is the 802.11n.

The 802.11n can work on either 2.4 or 5 GHz and it is the most recent standardized WiFi protocol (until 802.11ac gets approved). In order to use 802.11n over the 5 GHz frequency, you need a special router that can provide this functionality.

If you are already an owner of that sort of wireless router, all you need to do is use the SSID for the 5 GHz and your issues should stop, if not you need to purchase a router that can provide this functionality.

The device I purchased for that purpose is the Cisco/Linksys E2500 router:

Other routers that are dual band can also provide that functionality, but from my experience this specific router did the job.

Once the router is available, it can either replace your existing WiFi router, or if you have a router that is also a cable modem (has a coax cable connected to it, like the Verizon FiOS router), you can configure it to act as an access point by selecting the Bridge Mode in the 'internet connection' settings and plugging it to the back of your router.

That's it for this post, if you find it helpful but need more details about how to setup the router, comment below and I'll answer or create another post with more details.

*** Update: here is a link to a post about how to configure the linksys ruter for bridge mode Linksys wireless router config for bridge mode

Wednesday, March 21, 2012

CCIE voice renewal afterthoughts

* This is the second post on the CCIE voice renewal subject, for the first post, please click here.

Well, It took longer then I thought but I'm finally done for the next couple of years.

The delays had to do with some high priority meetings and tasks that required my full attention and didn't allow the required prep time. Since it is a $350 test, I chose to wait a little longer.

This brings me to think that the appropriate time to kick off the prep should be the 100 day mark, not the 60 like I said before. Since 60 turns into 30 pretty fast when you work in a full time job.

The CCIE in general and the voice CCIE in particular, are not a task that can be taken lightly. This test was and still is a tough one to pass, although it's 'just' the written, it's still hard. The required test (350-030) is a two hour test, which can have 90 to 110 questions! That's almost double the amount of questions from a typical 640-xxx test (ccna and ccnp). And in those tests you get 90 minutes. The simple math around it is that in a ccnp and ccna test you have around 90 seconds per question and in the CCIE voice you have 60 seconds.

Time management is crucial here, make sure to spend up to a minute per question and move on. When in doubt, use logical elimination and proceed, there are low hanging fruits at the end of the test and if you spend too much time in the beginning, you would loose them as well.

As for the prep material to the CCIE-V, the Call Manager SRND is a must, but you also need to learn those of the Call Manager express and the Contact Center Express SRND.

Some books that are available online are listed below, the first one is good for an overall reference source when doing a quick review/refresh of the knowledge and the second one is good for IOS related prep and catchup on Gateway and Gatekeeper and QoS:


Practical knowledge is also needed, do some labs and make sure you can configure a Call Manager, Gateway, CCX, presence etc.

Practice questions are important, but should only be used after you did all the reading and the labs. Those that jump right to them and try to memorize the test, are going to miss the point of the test and potentially fail, since the test is designed to trick the memorizers.

That's it, good luck and feel free to ask questions using the comments section below.

Friday, February 10, 2012

CCIE Voice renewal study notes

It starts with an email, which comes six months before the due date, but six months are more than enough and the email is archived and forgotten.

Then, at three months another email reminder, this time it has a large CC list, still in the normal time frame and this one is left in the inbox as a reminder, but is quickly forgotten.

Thirty days passes fast and at sixty days another reminder is sent, again with the same CC list and this one is usually the one that triggers the learning activities and makes a typical certified engineer to step in and get the renewal going.
If you wait until it's thirty days before, it may be hard to finish on time and a project can turn into a priority.

Renewing a CCIE is accomplished by taking a written exam, from any track. If you׳r planning on another CCIE it makes sense to study and take the new track's test, but if not, the quickest route is to take the one you already have.

There aren't any official study material or textbooks for this test, independent authors have wrote a guide here and there (including myself a few years ago), Cisco press has a quick reference guide available, which can be purchased in amazon at:

CCIE Voice v3.0 Quick Reference
But the ultimate learning guide was and still is the Unified Communication SRND (Solution Reference Network Design).
Since there are more than a few versions of this doc, I'm planning to focus on the one that is in the same version as the published version of the lab, version 7.x

The SRND is a > 1000 pages document, if it's your first attempt with the voice written, it's probably not the best way for you, but if you are only renewing, it's a good resource to catch up on latest deployment modules of cucm.

Once the SRND is scanned and weak issues are covered, practice questions are used to test the level of understanding and identify week points. I'm not suggesting to use any of the NDA violating questions, but instead looking for legitimate sources that would have them. For every question that you are not sure or have doubts, go back to the SRND or your favorite book and learn the entire subject. If you are not sure about the bandwidth requirements for G.729 in layer 2 over ethernet, figure out how to calculate the required bandwidth for G.729 on ethernet, frame relay and multilink ppp and also for G.711, iLBC and G.722.

Two questions are available online at:

You can also use the CCNP Voice (CCVP) books, at the end of each module there are practice questions. If your books are outdated than its probably not a great idea to use them.

It also appears that on Amazon there is a product by IPExpert with practice questions:

CCIE Voice Written Test Prep Quizzer

Once most of the questions can be answered and you feel confident enough to take the test, schedule and take it. If you fail, learn from your mistakes and go for it again.

Good luck, I'm planing to reflect on the test in a week or two, once I'm done with it.

*** here is what I had to say after taking the test.

Saturday, January 21, 2012

ISR 819 cool video and what is Machine to Machine (M2M)

This is a real nice video that I had to share:

So what is M2M and where can those routers be used (besides a dog food plate)?

M2M is a way to provide an on demand connection without people operating it. It can be used for temperature sensors that need to 'call home' and report about current readings or for ATM machines that need to validate credentials. 

Its not new but Cisco did not have a device that could do it over multiple connections (3G, wifi, wired), at that price level and with a hardened option.

Besides, its a cool video :)