Posts Tagged ‘cisco’

How To Choose A Managed Network Services Provider

Monday, August 9th, 2010

New technology is wonderful for organizations. It allows users to be more effective, provides cost savings, and keeps the company ahead of their competitors by allowing them to provide better customer service. Experienced network administrators, however, know that the more capable technology gets the harder it is to keep it running. Managed network services can provide the required support.

Companies know that they have to hire consultants to design, deploy, and train them on new technology. They are also accustomed to paying yearly maintenance for manufacturer’s support on software or hardware. What is normally left to the Information Technology department is the knowledge and capability to know how everything works together. What companies are starting to figure out is that the ongoing support necessitates a higher level of knowledge and experience than internal Information Technology staff typically possess.

That is why there is such a noticeable trend toward hosted IT services. The hosted service providers have a good point in their marketing that it takes advanced skills to operate advanced technology.

What is often not discussed is that having outsourced applications means that a business’s internal network has to be even more reliable and secure while operating at a higher level than ever. It demands a lot of skill and experience to be able to operate today’s advanced LAN’s and WAN’s, especially when they are running converged applications over them like voice and video, while keeping everything secure.

Due to these advanced operational requirements, many businesses are contracting with a managed network service to assist them in maintaining their advanced data networks in optimum working order. It is tempting to turn over the responsibility for the entire network to a big service provider that will promise to handle any issues. Unfortunately, because many of these service providers offer remote support only, when it comes time for design, deployment, or having someone on site for local troubleshooting, they are not able to handle it.

Most organizations would like to work with a local managed network service provider, for many of the same reasons that they use local companies for other services they contract out. To get good quality managed services from local providers, it is best to find out what they specialize in, and inquire if they partner with other local providers for other aspects of support. Another possibility is to contract with a local provider who resells and provides local on site services for a larger service provider.

Think of these local providers as an extension of the organization’s IT staff. Manufacturer support on products is still important. The manufacturer’s support most often includes product upgrades, phone and/or email technical support, and product replacement within either a 4 hour or next business day timeframe. This is an important part of maintaining system uptime.

When evaluating managed network services providers for extended support, check their references with care, make sure all costs, services, and expectations are agreed upon in writing up front. Moreover, make sure there is a clause to cancel the agreement within a reasonable timeframe.

Look at this Cisco managed services description from a managed network services provider.

Suggestions For CCNA/CCNP Labs

Friday, March 5th, 2010

Many people ask me what would make a good CCNA lab? Well, that can be a tricky question based upon your budget and future Cisco aspirations. So let’s start off with a few basic concepts I hope we can all agree on. Real Routers

You need a physical router as the simulators just don’t have the ability to give you the “hands on” you need to see what happens when you disconnect a cable, put a cable in the wrong location or just plain configure the interface incorrectly. Dependant on what you do by mistake, you may see either the interface or protocol go down and based upon that it should give you a clue of where to start troubleshooting(hint, what layer is the interface at and what layer is the protocol at?). Anyway, you will come to find quite quickly that mistakes you make on Router 1 are affecting Router 4 all because you did not screw in a cable properly. No simulator can simulate that, so a router is invaluable.

I also get occasionally asked if someone can use their D-Link “router” or such in their lab. That class of home “router” generally does not support protocols such as RIP, OSPF, IGRP, etc. nor do they support the Cisco IOS which is a majority of the CCNA exam. So the answer is they are not really applicable to building your Cisco CCNA lab.

How Many Cisco Routers Do I Need?

Two routers really are required to see if anything works. If you have a very limited budget, you can receive value from only purchasing a single router over working with a simulator. However, you will not be able to see the main thing we are trying to accomplish. The propagation of route tables and the routing of data! The only way you can see if your configurations work, is to have at least two routers. That said, if you can afford a kit with more than two routers, it will enable you to exercise more complex scenarios. Therefore, I strongly recommend that you purchase a dual router kit or better that comes with all the accessories you need. Otherwise you can spend days or weeks trying to find all the little extra pieces you need to get your lab up and running. I mention this as some other resellers are selling their kits with 2500 routers and they are not including transceivers. Well how will you use the Ethernet AUI ports without them?? So this is basically how I view it. One router will give you the ability to run the commands on it and allow you to memorize the correct syntax and context in which to run the commands. Two routers will allow you to be able to see route table information propagate, data propagation and path election. In addition, you will see basic device elections. With three or more routers you will get all of the above and full device elections. Hopefully these tips will help you pick the right CCNA lab kit for you budget.

Can We Build A Lab That Will Cover Every Single CCNA Exam Concept?

We get this question quite often. Yes, we can, but it is not realistic for most customers who are self studying as this will cost well in excess of $5,000. If you have that sort of budget available, we suggest you pick on of the CCNP kits as that will get you through your CCNA exam and well on your way to your CCNP certification.

How Many Cisco Routers & Cisco Switches Do I Need To Complete Your CCNA Lab Workbook?

Our CCNA Lab Workbook was designed with the knowledge that most of our customers can’t afford a large lab. Keep in mind, that you will see a variety of labs that were written for three of four routers below. That does not mean you can’t complete most of them. It just for the most part means they will not be as complex as they could be.

Number of labs requiring only one router – 7

Number of labs requiring two routers – 11

Number of labs requiring three routers – 19

Number of labs requiring four routers – 4

Number of labs requiring one or more switches – 8

Now you can review the above link for our CCNA Lab Workbook to see all the topics covered. A physical copy of the Lab Workbook is included with our dual router or better kits. Now we have had a request by some customers who are not buying a full kit from us to just download a copy of the Lab Workbook or they want to preview the Lab Workbook. Well, we now offer a preview version of the Lab Workbook which you can download and view some of the labs and chapters. It is available at this link… CCNA Lab Workbook eBook Download Keep in mind, if you order the download version, you do not get a physical copy of the book. You only get a physical copy of the book if you order it from this link in which case it is shipped to you CCNA Lab Workbook. What Are Some Things I Need To Consider For My CCNA Lab?

Two new topics have popped up for the new Cisco CCNA 640-802 exam. They are IPv6(IP Version 6) and SDM(Security Device Manager) which is a GUI based way to configure your routers and switches. A common question is can the Cisco 2500 series routers support IPv6? Yes, they can if they are maxed out with 16MB of DRAM and Flash. Here are some more specs on Cisco routers and required DRAM and Flash to support IPv6 assuming you have the correct IOS. To make your life a little easier, I have included a handy chart illustrating the minimum DRAM and Flash required to support IPv6 per model platform below.

DRAM/Flash Memory Required for Feature Support

Model IPv6 SDM Max IOS Ver. Cisco 2500 16/16 Not Available 12.3 Cisco 2600 64/16 Not Available 12.3 Cisco 2600XM 128/32 128/32 12.4 Cisco 3620 64/16 Not Available 12.3 Cisco 3640 128/32 64/16 12.4 If you took a good look at the chart, you will also notice I mentioned the requirements for SDM too. As mentioned before, SDM is Cisco’s Security Device Manager and is the GUI option to configure your routers. It is not supported on some of the older models. But the good news from a lab perspective is that you do not need it on every router to get a good grasp on how SDM works. The Cisco 3640 router is going to be the cheapest way to get SDM with a 10mb Ethernet interface and the Cisco 2600XM series seems to be the cheapest way to get SDM with a 100mb Ethernet interface.

Finally, I also have an IOS version column. As you can see above, the Cisco 2500, 2600 and 3620 models only support 12.3 whereas the Cisco 2600XM and 3640 units support 12.4. So if you want to have exposure the latest IOS that is running on routers in the real world, right now that is 12.4. But if your budget does not allow for it, you will still find value in the routers that are running the older 12.3 IOS.

Why Do You Sell Routers With Memory That Can’t Run IPv6?

Not everyone has the budget to support every feature. So you will see that we still offer Cisco 2500 router kits with 8MB of DRAM and 8MB of Flash as being able to practice on routers that support 85% of the concepts is better than nothing at all if you budget is tight.

How Do I Know What Interfaces & Options Are Available On A Router?

In an effort to avoid any confusion and give you one place to look to compare models and interfaces/options, I made this next handy little chart to give you an idea of what to expect on each router.

Summary of Router Interfaces

Model Ethernet Sync Serial (DB-60) Async/Sync Serial Ports NM Slots Available Wan Slots Available Cisco 2501 1- AUI 10mb 2 0 0 0 Cisco 2503 1- AUI 10mb 2 0 0 0 Cisco 2507/16 16 Port Hub10mb 2 0 0 0 Cisco 2514 2- AUI 10mb 2 0 0 0 Cisco 2520 1- AUI 10mb 2 2 0 0 Cisco 2610 1- RJ-45 10mb 0 0 1 2 Cisco 2611 2- RJ-45 10mb 0 0 1 2 Cisco 2612 1- RJ-45 10mb 0 0 1 2 Cisco 2610/20XM 1-RJ-45 100mb 0 0 1 2 Cisco 2611/21XM 2-RJ-45 100mb 0 0 1 2 Cisco 1720 1- RJ-45 100mb 0 0 1 2 Cisco 2620 1- RJ-45 100mb 0 0 1 2 Cisco 2621 2- RJ-45 100mb 0 0 1 2 Cisco 3620 0 0 0 2 0 Cisco 3640 0 0 0 4 0 1 AUI = attachment unit interface. Anything Else You Can Suggest?

Well, a few things. The Cisco 2500s are serviceable routers for your CCNA studies still as long as you have the proper IOS and maxed out memory with all the accessories you need. You might say, but they are only 10mb routers. True, but they still work. The major drawback besides the aforementioned lack of SDM and 12.4 support is that with 10mb routers you can’t do your inter-vlan routing labs with them(which is true of any of the 10mb routers). So just make sure you have at least one 100mb router in your lab so you can do inter-vlan routing and that takes care of that issue and helps to keep the cost of your lab down for those with a tight budget!

You want to make sure your router can support IPv6 as doing those labs will really help the IPv6 concepts sink in. Finally, SDM is more than likely the wave of the future, so you might as well start to get used to it now!

What Is the CiscoKits Trade-Up Program?

In a nutshell something no other vendor is willing to offer to you! For any routers or switches you purchase from us, we will allow you to trade it in for a higher priced router or switch in the future as your Cisco certification lab grows. We are here to see you all the way up to CCIE as your Cisco certification partner! Please see the Trade-Up Program link on the left for full program details.

Do I Need A Switch?

This can be debated a few different ways. First some people will say that 80% of the test is based on routing. To which I will agree. But with only a small margin of error between passing and failing, not fully understanding switching concepts such as VLANs, STP, and root elections could be the one question that stands between you passing and failing your exam. There will be some switch questions which are memorization based such as “What is a Layer 2 protocol used to maintain a loop-free network?” Thank goodness we memorized STP. That said, it would be nice for us to be able to actually “see” the switching concepts work. So this is basically how I view it. One switch will give you the ability to run the commands on the switch and allow you to memorize the correct syntax and context in which to run the commands. It will also allow you to do some of the VLAN labs. Two switches will allow you to see VTP Domain & VLAN information propagate. In addition, you will see basic device elections. With three or more switches you will get all of the above and full device elections. Remember, we are only at the CCNA level right now so we will not need a Layer 3 switch like a 3550 just yet. But it is a cool concept of your CCNP studies. Finally you may ask why do some of my dual router kits not have switches in them. Well because you can quite simply go to the section on our site labeled Switches and add the switch you would like to be a part of your kit. The switches don’t need extra transceivers, ports and such so I don’t really have to kit them up with the routers. We do have some of the larger kits that have both routers and switches in them too.

What Switch Should I Get?

This is one that there is so much debate on these days. I will give you my thoughts on it and there are a hundred different ways you can build a lab. I will give you the information and let you decide how you want to build your lab.

The Cisco 2950 switch is the switch that is covered on the test and has the exact IOS command set that you will see on the lab. So if you can afford one, it is great to get. But sometimes when customers only have a $200 budget, I can’t suggest for them to get a switch and forego the routers. After all, the test is 80% routing! Back to the Cisco 2950, this is the best switch for the test if you can afford it.

But let’s say you can’t afford that switch , but still want a switch, what is next? We have the Cisco 2900 series. This is a step down from the Cisco 2950 and supports all the same CCNA test commands except the switchport and global vlan command. So with that knowledge, this switch may just work for you.

Finally, there is the Cisco 1900 series switches. There is not a lot of demand for these so they can be purchased very cheap. Some people say they have absolutely no value in a CCNA lab. I tend to disagree for the most part. You may ask me, hey, what are you smoking? The IOS that the Cisco 1900 series switches support is not the IOS that is on the test so how can it be useful? Well, let’s go into knowing that they IOS commands on the 1900 series are not the ones that are on the test. Ok, so we are not going to focus on them(remember, there are only a very few switch IOS commands on the CCNA exam in regard to syntax), but concepts that I find many people having a hard time understanding in how STP works, how the device elections are handled and such. Those concepts work exactly the same way on a 1900 as they do on the 2950 switch. Not to mention that you can do your VLAN, VTP and other similar labs on the switch to get an understanding on how they work. So hopefully you can see why I still carry them to help customers who are on a tight budget get exposure to such concepts. *Note, as of January 2009 the prices have come down on the 2900 series switches to the point it does not seem to be of great value for us to still carry the 1900 switches. The price between the two switch types is so close it is better to spend the extra few dollars and get a 2900 series switch.

As I did with the routers above, I have also included a switch feature chart below to help you make your Cisco switch selection.

Summary of Switch Features

Summary of Cisco Switch Features 1912/1924 2912/2924 2950 3550 Port Speed 10/100MB 100MB 100MB 100MB VLans X X X X Trunking X X X X Port Aggregation X X X X Mirroring X X X X ISL X X 802.1Q X X X QoS X X Layer 3 Switching X IOS Version 9.007 12.x 12.x 12.x

How to build your Cisco CCNP or Cisco CCIE Lab

Feel free to review our Cisco CCNP and Cisco CCIE Certification lab suggestion articles below:

Cisco CCNP Lab Suggestions

Cisco CCIE Lab Suggestions

Go to CiscoKits for your free Cisco Certification training. Cisco CCNA,CCNP,and CCIE training along with many options for Cisco home lab kits!

Creating a Static Route Using 3 Cisco Routers

Wednesday, January 27th, 2010

In preparation of your CCNA exam, we want to make sure we cover the various concepts that we could see on your Cisco CCNA exam. So to assist you, below we will discuss one of the more difficult CCNA concepts; the Three Router Static Route Lab. As you progress through your CCNA exam studies, I am sure with repetition you will find this topic becomes easier. So even though it may be a difficult concept and confusing at first, keep at it as no one said getting your Cisco certification would be easy!

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Objective In this lab, you will configure static routes between all three routers. This will allow your routers to route packets so that all routers and all hosts will be able to reach (ping) each other. Once your configuration is complete, you will use basic techniques to test your network’s connectivity.

Scenario Three separate classful networks need routing between them and their subnets.

Questions: What are the different classful networks? 1. ________________ 2. ________________ 3. ________________ 4. ________________ 5. ________________ Are there any subnets? If so, what are they? 1. _______________ 2. _______________ 3. _______________ 4. _______________ 5. _______________ Setup Configure the cabling as shown in the network diagram If the routers have a startup-config, erase it and perform a reload of the routers. Important! Configure the routers to include hostnames and the proper interface commands including IP addresses, subnet masks, etc. Each router should be able to ping the interface of the adjacent (neighboring) router and the host on its LAN (Ethernet) interface. Test and troubleshoot as necessary. Use the context sensitive help, previous labs, your books and /or handouts and if your still having problems ask your partner or ask the instructor for assistance. Step 1 – Configuring Static Routes On each router configure a separate and specific static route for each network or subnet. You do not need to configure static routes for the router’s directly connected network(s) because like a host, by configuring the IP address and subnet mask on an interface tells the router that it belongs to that network/subnet.

Router1 Router1(config)# ip route 172.16.3.0 255.255.255.0 172.16.2.1 Router1(config)# ip route 192.168.2.0 255.255.255.0 192.168.1.1 Router2 Router2(config)# ip route 172.16.1.0 255.255.255.0 172.16.2.2 Router2(config)# ip route 192.168.1.0 255.255.255.0 172.16.2.2 Router2(config)# ip route 192.168.2.0 255.255.255.0 172.16.2.2 Router3 Router3(config)# ip route 172.16.1.0 255.255.255.0 192.168.1.2 Router3(config)# ip route 172.16.2.0 255.255.255.0 192.168.1.2 Router3(config)# ip route 172.16.3.0 255.255.255.0 192.168.1.2 Verify and Validate: All hosts and all routers should be able to ping every interface in the network. Do a “show running-config” and notice the static routes that you entered. Router# show ip route o What routes to networks do you see? o Which routes are static and which routes are directly connected? o What is the administrative distance for a static route? o What is the administrative distance for a directly connected network? Questions: How does the next-hop-ip-address help with the routing process? _____________________________________________. Does it give the entire route, i.e., subnet mask? _________________ What is it actually doing regarding the routing of the packet? ____________________________________________ How does a packet get from Host 2 to Host 3? ____________________________________________ ____________________________________________ ____________________________________________ Instead of a next-hop-ip-address, what else could you have used? ____________________________________________. What would you need to do if you added new networks or deleted/modified existing networks? ____________________________________________ ____________________________________________ ____________________________________________ Is there any way to summarize several static routes to multiple subnets into a single static route? _____________________________________________ _____________________________________________ _____________________________________________ Outputs Router2#show ip route (Output omitted) Gateway of last resort is not set

172.16.0.0/24 is subnetted, 3 subnets S 172.16.1.0 [1/0] via 172.16.2.2 C 172.16.2.0 is directly connected, Serial0 C 172.16.3.0 is directly connected, Ethernet0 S 192.168.1.0/24 [1/0] via 172.16.2.2 S 192.168.2.0/24 [1/0] via 172.16.2.2

Router1#show ip route (output omitted) Gateway of last resort is not set

172.16.0.0/24 is subnetted, 3 subnets

C 172.16.1.0 is directly connected, Ethernet0 C 172.16.2.0 is directly connected, Serial0 S 172.16.3.0 [1/0] via 172.16.2.1 C 192.168.1.0/24 is directly connected, Serial1 S 192.168.2.0/24 [1/0] via 192.168.1.1

Router3#show ip route (Output omitted) Gateway of last resort is not set

172.16.0.0/24 is subnetted, 3 subnets S 172.16.1.0 [1/0] via 192.168.1.2 S 172.16.2.0 [1/0] via 192.168.1.2 S 172.16.3.0 [1/0] via 192.168.1.2 C 192.168.1.0/24 is directly connected, Serial0 C 192.168.2.0/24 is directly connected, Ethernet0

Step 2 – Configuring Summary Static Routes The configuration of the routers in Step 1 works just great and is a valid way to configure routing on these networks. Earlier, we noticed that the network 172.16.0.0 is divided into several subnets. The Router3 router does not really need separate static routes for each subnet, since all of the 172.16.0.0 subnets can be reached via the same next-hop-ip-address, i.e. Router1. Let’s reconfigure the static routes on Router3 so that it only uses a single static route to reach all of the 172.16.0.0 subnets.

Router1 No changes Router2 No changes Router3 First, remove the current static routes: Router3(config)# no ip route 172.16.1.0 255.255.255.0 192.168.1.2 Router3(config)# no ip route 172.16.2.0 255.255.255.0 192.168.1.2 Router3(config)# no ip route 172.16.3.0 255.255.255.0 192.168.1.2 Now, add the new summary static route: Router3(config)# ip route 172.16.0.0 255.255.0.0 192.168.1.2 Verify and Validate: All hosts and all routers should be able to ping every interface in the network. Do a “show running-config” and notice the static routes that you entered. Router3# show ip route o What routes to networks do you now see? Questions: What made this new summary static route work for all subnets? _____________________________________________________ _____________________________________________________ _____________________________________________________ Why is a single summary static route an advantage regarding the size of the routing table? _____________________________________________________ _____________________________________________________ _____________________________________________________ Why is a single summary static route an advantage regarding future changes to the 172.16.0.0 network? _____________________________________________________ _____________________________________________________ _____________________________________________________ Outputs Router3#show ip route (Output omitted)

Gateway of last resort is not set S 172.16.0.0/16 [1/0] via 192.168.1.2 C 192.168.1.0/24 is directly connected, Serial0 C 192.168.2.0/24 is directly connected, Ethernet0

Step 3 – Configuring Default Static Routes Both Step 1 and Step 2 are acceptable ways to configure routing for these networks. We notice that the 172.16.3.0/24 and the 192.168.2.0/24 networks are “stub networks,” meaning that there is only one way out (both via Router1).

Router1 No changes Router2 First, remove the current static routes: Router2(config)# no ip route 172.16.1.0 255.255.255.0 172.16.2.2 Router2(config)# no ip route 192.168.1.0 255.255.255.0 172.16.2.2 Router2(config)# no ip route 192.168.2.0 255.255.255.0 172.16.2.2 Now, add the new default static route: Router2(config)# ip route 0.0.0.0 0.0.0.0 172.16.2.2 Router3 First, remove the current static routes: Router3(config)# no ip route 172.16.0.0 255.255.0.0 192.168.1.2 Now, add the new default static route: Router3(config)# ip route 0.0.0.0 0.0.0.0 192.168.1.2 Verify and Validate: All hosts and all routers should be able to ping every interface in the network. Do a “show running-config” and notice the static routes that you entered. Router2# show ip route o What routes to networks do you now see? Router3# show ip route o What routes to networks do you now see? Questions: Do you think static routes are still used even with dynamic routing (RIP, OSPF, etc.)? _______________. Hint: Think about the administrative distance. Do you think default static routes are still used even with dynamic routing (RIP, OSPF, etc.)? _______________. What is the disadvantage of doing this? How would a default static route be properly used in a real world network? (How would a company’s network use a default route when connecting to the Internet?) ________________________________________ ________________________________________ ________________________________________ Outputs Router3#show ip route (Output omitted)

Gateway of last resort is 192.168.1.2 to network 0.0.0.0

C 192.168.1.0/24 is directly connected, Serial0 C 192.168.2.0/24 is directly connected, Ethernet0 S* 0.0.0.0/0 [1/0] via 192.168.1.2

Save your current configuration to NVRAM.

End of Lab I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. Achieving your CCNA certification is much more than just memorizing Cisco exam material. It is having the real world knowledge to configure your Cisco equipment and be able to methodically troubleshoot Cisco issues. So I encourage you to continue in your studies for your CCNA exam certification.

Go to CiscoKits for your free Cisco Certification training. Cisco CCNA, CCNP, and CCIE training along with many options for Cisco home lab kits!

Used Cisco Routers Can Help You Save A Significant Amount Of Cash

Sunday, November 22nd, 2009

It’s certainly not an straightforward task to drive a business efficiently, particularly in this economic scenario. However, this can be the only way that we tend to will survive particularly throughout this time. After all, almost all the companies are trying their best reducing their price as so much as attainable in virtually everything, particularly where we tend to have the options to travel in for used things. The best example for this can be the network infrastructure.

But, how will this be possible that a company is able to save lots of a good quantity of money and still ought to be in a position to better of the networking equipment ever out there? Well, we tend to all are aware of Cisco System Products. In fact anyone can vouch for the standard of the networking equipments that are obtainable within the market. These equipments show nice performance and are highly valued even when wear and tear. Quite some of the businesses eliminate such equipments that are no longer being utilized by them, but these will well be refurbished and used.

One among the foremost necessary products to be mentioned here would be Cisco Routers. The most facet that sets the Cisco routers different from the PCs is the fact that these routers will be used for performing exceptional tasks like routing likewise controlling the traffic between any variety of pc networks, which is the foremost essential part in any company. It will not be wrong to call these routers as good items of network devices, that encourage be quite essential in the networking of the systems in the company. Try considering the Cisco hardware, particularly the Cisco routers for understanding the functioning and the performance of the routers. The only factor is that these Cisco routers are a bit expensive. Therefore, you have the choice of going ahead with the used routers, as these are obtainable at a better worth in the market. Due to the present reason, there are several companies, that sell used Cisco routers.

Therefore, you’ll be able to certainly save a nice deal of cash by either selling or buying used networking equipments. It conjointly makes a significant difference in the value that you’ll must incur. With simply a very little little bit of amendment in the standard of the merchandise, that is instead of new, if you’re going ahead with used routers, and avoid wasting tons to thousands of bucks, the nit is certainly worth it. The money that’s being saved by purchasing the used Cisco routers can be used elsewhere in the business.

There are several strategies of selling and buying the used Cisco Routers and also different networking equipments. As a matter of reality, there are several companies that are successfully running this business and selling Cisco routers. These product also are accessible on-line on various websites. All you need to try to to is find the exact one that you are looking for and run your show.

Information Computers have successfully been one amongst the companies with a proven track record and experience of catering to shopper needs of reliability with value-effectiveness by providing a wide range of Used Cisco routers and switches.

Cisco CCNA Certification – Cisco VTP VLAN Trunking Protocol

Tuesday, September 1st, 2009

(VTP) is a Cisco Layer 2 messaging protocol that manages the addition, deletion, and renaming of VLANs on a network-wide basis. Virtual Local AreaNetwork (VLAN) Trunk Protocol (VTP) reduces administration in a switched network. When you configure a new VLAN on one VTP server, the VLAN is distributed through all switches in the domain. This reduces the need to configure the same VLAN everywhere. VTP is a Cisco-proprietary protocol that is available on most of the Cisco Catalyst Family products. VTP ensures that all switches in the VTP domain are aware of all VLANs. There are occasions, however, when VTP can create unnecessary traffic. All unknown unicasts and broadcasts in a VLAN are flooded over the entire VLAN. All switches in the network receive all broadcasts, even in situations where few users are connected in that VLAN. VTP pruning is a feature used to eliminate (or prune) this unnecessary traffic. By default, all Cisco Catalyst switches are configured to be VTP servers. This is suitable for small-scale networks where the size of the VLAN information is small and easily stored in all switches (in NVRAM). In a large network, a judgment call must be made at some point when the NVRAM storage needed is wasted, because it is duplicated on every switch. At this point, the network administrator should choose a few well-equipped switches and keep them as VTP servers. Everything else participating in VTP can be turned into a client. The number of VTP servers should be chosen so as to provide the degree of redundancy desired in the network.

Modes of OperationServer

In VTP server mode, you can create, modify, and delete VLANs and specify other configuration parameters (such as VTP version and VTP pruning) for the entire VTP domain. VTP servers advertise their VLAN configuration to other switches in the same VTP domain and synchronize their VLAN configuration with other switches based on advertisements received over trunk links. VTP server is the default mode.

Transparent

VTP transparent switches do not participate in VTP. A VTP transparent switch does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received advertisements. However, in VTP version 2, transparent switches do forward VTP advertisements that they receive out their trunk ports.

Client

VTP clients behave the same way as VTP servers, but you cannot create, change, or delete VLANs on a VTP client.

Advertisements Summary Advertisements

When the switch receives a summary advertisement packet, it compares the VTP domainname to its own VTP domain name. If the name is different, the switch simply ignores the packet. If the name is the same, the switch then compares the configuration revision to its own revision. If its own configuration revision is higher or equal, the packet is ignored. If it is lower, an advertisement request is sent.

Subset Advertisements

When you add, delete, or change a VLAN in a switch, the server switch where the changes were made increments the configuration revision and issues a summary advertisement, followed by one or several subset advertisements. A subset advertisement contains a list of VLAN information. If there are several VLANS, more than one subset advertisement may be required in order to advertise them all.

Advertisement Requests

A switch needs a VTP advertisement request in the following situations:

The switch has been reset. The VTP domain name has been changed. The switch has received a VTP summary advertisement with a higher configuration revision than its own. Upon receipt of an advertisement request, a VTP device sends a summary advertisement, followed by one or more subset advertisements.

Configuration To configure an IOS based switch to be a VTP server, issue the following commands: SwitchA# vlan database

SwitchA(vlan)# vtp domain CiscoKits

SwitchA(vlan)# vtp server

SwitchA(vlan)# exit

These commands configure the switch to be a VTP server in the VTP domain CiscoKits. The changes are saved and the revision number is incremented when the exit command is issued. To configure a VTP client, run the following commands:

SwitchB# vlan database

SwitchB(vlan)# vtp domain CiscoKits

SwitchB(vlan)# vtp client

SwitchB(vlan)# exit

To disable VTP, set the vtp mode to transparent as such:

SwitchC# vlan database

SwitchC(vlan)# vtp transparent

SwitchC(vlan)# exit

To monitor the VTP operation and status, use either:

SwitchA# show vtp status

SwitchA# show vtp counters.

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