![]() Your job: find the subnet/mask combination that you would configure in a manual summary route to replace all the routes with one summary route. Your task: Imagine that each column of Table 1 lists subnet/mask combinations that exist as routes in some router’s IP routing table. ![]() Unsure as to what that means? Check out this post that explains more about route summarization. Your job: choose the subnet/mask pair to use as the best summary route that includes the addresses in all the routes in the original list. Each problem lists a set of subnet/mask pair for existing routes in some router. The underlying skills require a fair amount of mastery of sub netting, so doing these drills can help prove you are ready for the toughest sub netting the CCNA has to offer. Want proof you are ready for #CCNA? Try these route summary drills. ![]() But the exercise set-up was based on the definition I gave to start the series at. For instance, your answer includes fewer addresses from outside the original subnets, but it includes some, so you have a different definition of “best summary”. However, you are correct in that if you want to avoid including addresses inside the summary that are not in the originally listed subnets – a different definition of the “best’ summary – then you would indeed find a different result. … best summary generally means the summary route that includes all the addresses in the original subnets, but is the smallest such subnet. In that post, I explain how we determine “best” in this context. I did supply my definition for best, back in the first post in the series, where I give some background on summary routes. So, the key to your question is your comment: “The solution you propose include a too many other addresses…” So, what rules do you use to decide if a summary has too many extra addresses? It all reduces to how you define what’s allowed in a summary route. Problem 3, Calculation Using 192.168.1.72, New /P Mask Problem 3, Original Subnets and Broadcast Addresses Mask The following table lists the original masks and subnets, the calculated broadcast addresses for each, and notes the lowest and highest numbers in the range in bold. Problem 2, Calculation Using 172.16.204.0, New /P Mask Problem 2, Original Subnets and Broadcast Addresses Mask Problem 1, Calculation Using 10.100.0.0, New /P Mask Note that the bold entry in the table is the correct answer. If not… the table shows a calculation, using progressively smaller masks, calculating a new subnet ID and matching broadcast address, using the smallest original subnet ID. If you are using the literal process shown in aforementioned post about how to find summary routes, the next table shows the results of working repeatedly through step 4. Problem 1, Original Subnets and Broadcast Addresses Mask This last route also includes the entire range of addresses, and could be used as a summary, but is not considered the best summary route, because it includes an unnecessarily broad range of addresses. Note that the second table for each problem includes a final summary route with a mask (/P) one shorter than the correct best summary route. ( See this post for details about the process.) The table shows the calculations with each /P being 1 smaller than the previous, until it lists the correct answer. The table shows each successive calculation of a new subnet ID, using a new /P mask, and its broadcast address. The second table for each answer lists the calculation of potential correct answers, with the correct answer listed in bold. The best summary route will be the first subnet/mask combination found that includes both the low and high-end numbers. ![]() These tables also show the low and high end of the address range in total, with bold text for the lowest subnet ID (the low end of the range) and bold text for the highest subnet broadcast address (the high end of the range). The first table lists the original masks and subnet IDs of the routes that need to be summarized as one route, along with the calculated subnet broadcast addresses. The answer to each of the three problems uses two tables. Then come back here and check your answers. If you’ve not tried these problems yet, go back, check it out, and come up with the best summary route. #CCNA (and #CCENT) candidates, here are the answers to that earlier summary route practice set. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |