As you can see on my first email, I explained the mechanism I used to get the result of /18. At the end of my email says: Please explain! What is the way or "mechanism" you use to get it properly done with /21. I can see you are CCIE and of course it is a piece of cake for you BUT I am still in the learning process and I guess this is what this Distribution List is for. Can you kindly explain how you get to the conclusion of /21 in a faster way. Thanks in advance!
Date: Thu, 25 Jul 2013 20:04:41 -0500 Subject: Re: [OSL | CCIE_RS] FW: OSPF Summarization From: [email protected] To: [email protected] CC: [email protected] Why not get real specific? If you use a /21 subnet mask you would match .32 - .39 Obviously your 192 network isn't fitting in there On Thu, Jul 25, 2013 at 6:55 PM, Wilberth E. Lemaître <[email protected]> wrote: I was able to see the logic, if I use 3 bits the ranges would go like these: 10.0.0.0 - 10.0.31.255 10.0.32.0 - 10.0.63.255 10.0.64.0 - 10.0.95.255 As we can see, they will all catch in the second range. Correct me if I am wrong? From: [email protected] To: [email protected] Subject: OSPF Summarization Date: Thu, 25 Jul 2013 17:27:49 -0600 Hello community, I have a question in regards summarization. Let's say I have area 2 configured on a router, the advertised networks are the following: router ospf xxx network 10.0.32.1 0.0.0.0 area 2 network 10.0.33.1 0.0.0.0 area 2 network 10.0.34.1 0.0.0.0 area 2 network 10.0.36.1 0.0.0.0 area 2 network 192.168.0.2 0.0.0.0 area 0 I want to summarize area 2, the mechanism I use for summarization is the following and correct me if I am wrong. I look for the octet where the decimal number changes, or where the bits are not equal. As we can see this happens on the 3rd octet and I start using increments with each octet value: 128 64 32 16 8 4 2 1 I wonder myself which increment or which number would catch all of those into one advertisement counting from zero, in other words, how many binary digits I have to convert to 1 in order to do the summarization. Based on this scenario, 32 would catch less than what we need, 64 would be the perfect one, and I will need to convert only 2 bits (the first 2 bits) and my subnet mask would look like 11111111.11111111.11000000.00000000 and the network range would go like this: 10.0.0.0 - 10.0.63.255 10.0.64.0- 10.0.127.255 As we can see, if I use a subnet mask of 18, I will be including ranges that are NOT necessary. What would be the efficient summarization in order to accomplish this scenario? Please explain ;) Best regards, Wilberth _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs -- Marc AbelCCIE #35470(Routing and Switching) _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
