It was Hans who showed me something that would forever help me to relax and calm down; if ever I needed a break from the research or the writing or the editing, I just had to do what Hans showed me—how to juggle. Thank you Hans, for keeping me grounded. If you see me at any Networkers Conferences in the future, ask me and I may give you an impromptu speech on juggling as a means of relaxation—I now carry my juggling balls with me everywhere.
He is one of the smartest men I know. It was he who I constantly looked to when I needed someone to proof my journals. By his own words, his own journal has been written down three times: once after my lecture was done he wrote down commands, the second time after he tried the commands on the devices and he saw how they actually worked, and a third time to clean up the journal to make it something that he could easily use and follow. So to Colin I owe a big thanks and a copy of this book.
Networking Devices Used in the Preparation of This Book In order to verify the commands that are in this book, I had to try them out on a few different devices. Some of it is quite old. Those of you familiar with Cisco devices will recognize that a majority of these commands work across the entire range of the Cisco product line.
These commands are not limited to the platforms and IOS versions listed. In fact, these devices are in most cases adequate for someone to continue their studies into the CCNP level as well. This book is for those people preparing for the CCNA exam, whether through self study, on-the-job training and practice.
There are also some handy hints and tips along the way to hopefully make life a bit easier for you in this endeavor. This book will also be useful to network professionals who are not preparing for the CCNA exam yet need a quick reference to reinforce or refresh networking concepts and commands. Did I Miss Anything? I am always interested to hear how my students, and now readers of my books, do on both vendor exams and future studies.
Did I miss anything? Let me know. My e-mail address is ccnaguide empson. You need nine subnets. What is the IP plan of network numbers, broadcast numbers, and valid host numbers? What is the subnet mask needed for this plan? You cannot use N bits, only H bits.
Therefore, ignore These numbers cannot change. Step 1 Determine how many H bits you need to borrow to create nine valid subnets. Counting by Step 7 Verify pattern in binary third valid subnet in binary used here. Step 9 Calculate subnet mask. The default subnet mask for a Class C network is as follows: Decimal Binary The default subnet mask for a Class B network is as follows: Decimal Binary However, in the Binary Numbering system, the AND function yields only two possible outcomes, based on four different combinations.
The end result of ANDing these two numbers together is to yield the network number of that address. Question 1 What is the network number of the IP address Answer Step 1 Convert both the IP address and the subnet mask to binary: Refer to the truth table for the possible outcomes: Question 2 What is the network number of the IP address Notice that the IP address is the same as in Question 1, but the subnet mask is different.
What answer do you think you will get? The same one? Good question. The best answer is to save you time when working with IP addressing and subnetting. Remember that if two addresses are in the same network or subnetwork, they are considered to be local to each other, and can therefore communicate directly with each other. Addresses that are not in the same network or subnetwork are considered to be remote to each other, and must therefore have a Layer 3 device like a router or Layer 3 switch between them in order to communicate.
Question 3 What is the broadcast address of the IP address The last three bits are host bits. Step 4 Change all host bits to 1. Remember that all 1s in the host portion are the broadcast number for that subnetwork: Answer Therefore, any octet ANDed to a subnet mask pattern of is itself! Notice that the last octet is all 0s after ANDing. But according to the truth table, anything ANDed to a 0 is a 0.
Therefore, any octet ANDed to a subnet mask pattern of 0 is 0! You should only have to convert those parts of an IP address and subnet mask to binary if the mask is not or 0.
Question 5 To what network does Question 6 To what network does Answer Based on the two shortcut rules, the answer should be The Enhanced Bob Maneuver for Subnetting or How to Subnet Anything in Under a Minute Legend has it that once upon a time a networking instructor named Bob taught a class of students a method of subnetting any address using a special chart.
This was known as the Bob Maneuver. These students, being the smart type that networking students usually are, added a row to the top of the chart and the Enhanced Bob Maneuver was born. The chart and instructions on how to use it follow.
With practice, you should be able to subnet any address and come up with an IP plan in under a minute. He taught this maneuver to Bruce, who taught it to Chad Klymchuk. Chad and a coworker named Troy added the top line of the chart, enhancing it.
And the circle is complete. From that number 14 , move up to the line called Bit Place. Above 14 is bit place 4. The dark line is called the high-order line. If you cross the line, you have to reverse direction. You were moving right to left; now you have to move from left to right. Go to the line called Target Number.
Counting from the left, move over the number of spaces that the bit place number tells you. Starting on , moving 4 places takes you to This target number is what you need to count by, starting at 0, and going until you hit or greater. These numbers are your network numbers. Go back to the Enhanced Bob Maneuver chart and look above your target number to the top line.
The number above your target number is your subnet mask. Above 16 is Because you started with a Class C network, the new subnet mask is Remember that when you perform classful or what I sometimes call classical subnetting, all subnets have the same number of hosts because they all use the same subnet mask.
For example, if you borrow 4 bits on a Class C network, you end up with 14 valid subnets of 14 valid hosts. A serial link to another router only needs 2 hosts, but with classical subnetting you end up wasting 12 of those hosts. This is where VLSM comes in to play.
What you have to remember is that you need to make sure that there is no overlap in any of the addresses. IP Subnet Zero When you work with classical subnetting, you always have to eliminate the subnets that contain either all zeros or all ones in the subnet portion.
Consider Figure as you work through an example. Once again, you cannot use the N bits— You can use only the H bits. Therefore, ignore the N bits, because they cannot change! Step 2 Pick a subnet for the largest network to use. Step 3 Pick the next largest network to work with.
Step 4 Pick the third largest network to work with. Step 5 Determine network numbers for serial links. The remainder of the chapter details what is involved with each step of the process. Two borrowed H bits means a subnet mask of: Pick one of these subnets to use for Network A. The rest of the networks will have to use the other three subnets.
For purposes of this example, pick the. You started with a pattern of 2 N bits and 6 H bits for Network A. You have to maintain that pattern. For purposes of this example, select the. Therefore, you are left with: 10N where: 10 represents the original pattern of subnetting. N represents the extra bit. This is the basis of VLSM. Each of these sub-subnets will have a new subnet mask.
The mask now equals: You want to make sure the addresses are not overlapping with each other. So go back to the original table. You now have a choice as to where to put these networks. But you only need 4 H bits, not 5. Therefore you are left with: N where: 10 represents the original pattern of subnetting. N represents the extra bit you have. Each sub-subnet now has 4 N bits and 4 H bits, so their new masks will be: Now all you need to do is determine the network numbers for the serial links between the routers.
Step 5 Determine Network Numbers for Serial Links Serial links between routers all have the same property in that they only need two addresses in a network—one for each router interface. You have two of the original subnets left to work with. Therefore, you are left with: 00NNNN00 where: 00 represents the original pattern of subnetting. NNNN represents the extra bits you have.
This is the power of VLSM! Remember that for every route you advertise, the size of your update grows. It has been said that if there were no route summarization, the Internet backbone would have collapsed from the sheer size of its own routing tables back in !
Routing updates, whether done with a distance vector or link-state protocol, grow with the number of routes you need to advertise. The more routes you have to advertise, the bigger the packet. The bigger the packet, the more bandwidth the update takes, reducing the bandwidth available to transfer data.
But with route summarization, you can advertise many routes with only one line in an update packet. This reduces the size of the update, allowing you more bandwidth for data transfer. The larger the routing tables, the longer this takes, leading to more used router CPU cycles to perform the lookup. NOTE: This example is a very simplified explanation of how routers send updates to each other. This book has been around for many years and is considered by most to be the authority on how the different routing protocols work.
Example for Understanding Route Summarization Refer to Figure to assist you as you go through the following explanation of an example of route summarization. Without route summarization, Vancouver would have to advertise 16 networks to Seattle. You want to use route summarization to reduce the burden on this upstream router. What you are looking for are common bits on the network side of the addresses.
You are left with the summarized address of By sending one route to Vancouver with this supernetted subnet mask, you have advertised four routes in one line, instead of using four lines. The summarized route is therefore: You continue in the same format as before. Take the routes that Winnipeg, Calgary and Edmonton sent to Vancouver and look for common bit patterns: Figure shows what the routing updates would look like with route summarization taking place.
Route summarization can help insulate upstream neighbors from these problems. Consider router Edmonton from Figure Suppose that network Without route summarization, Edmonton would advertise Vancouver to remove that network.
Approximately 35 hours will be designated to lab activities and 35 hours on curriculum content. A case study on structured cabling is required, but format and timing are determined by the Local Academy. What has changed from CCNA versions 2. Course Outline Module 1. Introduction to Networking Overview 1. Networking Fundamentals Overview 2. Networking Media Overview 3. Cable Testing Overview 4. Ethernet Fundamentals Overview 6. Ethernet Switching Overview 8.
IP v6 9. Module Routing Fundamentals and Subnets Overview Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Next SlideShares. Download Now Download to read offline and view in fullscreen. Download Now Download Download to read offline. DH Da Lat Follow. What to Upload to SlideShare. A few thoughts on work life-balance. Is vc still a thing final. The GaryVee Content Model.
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