Deep_Level_Shark Posted June 21, 2017 Share Posted June 21, 2017 Can anyone please help me to understand this notation in an easy layman's way ? subnet CIDR 193.239.32.0/22 how many IP address are possible ? Link to comment Share on other sites More sharing options...
wakjak Posted June 21, 2017 Share Posted June 21, 2017 30 minutes ago, Deep_Level_Shark said: how many IP address are possible ? 1020? just taking a wild guess. Link to comment Share on other sites More sharing options...
Xahid Posted June 21, 2017 Share Posted June 21, 2017 You still need some basic knowledge to understand the sub-netting. you know IPv4 is 32bit address ? how? 8 bits + 8 bits + 8 bits + 8 bits =32bits 00000000 + 00000000 + 00000000 + 00000000 =32bits Now the question is how many IP's in 193.239.32.0/22 /22 means, its already sub-netted, and to calculate it, we have to slash the 22 bits from default 32 bits, remaining 10 bits. Now put those 10 bits in formula. 2^n -2 + 2.00 ^ 10.00 --------------- + 1,024.00 - 2.00 --------------- 1,022.00 So, you will have 1022 IP address in /22 Subnet. T3X4S, StrikedOut and Mando 3 Share Link to comment Share on other sites More sharing options...
StrikedOut Posted June 21, 2017 Share Posted June 21, 2017 Great explanation from Xahid. Also take a look at this video, helps to explain how to do this. Also feels like a homework question?? Link to comment Share on other sites More sharing options...
Deep_Level_Shark Posted June 21, 2017 Author Share Posted June 21, 2017 5 hours ago, Xahid said: You still need some basic knowledge to understand the sub-netting. you know IPv4 is 32bit address ? how? 8 bits + 8 bits + 8 bits + 8 bits =32bits 00000000 + 00000000 + 00000000 + 00000000 =32bits Now the question is how many IP's in 193.239.32.0/22 /22 means, its already sub-netted, and to calculate it, we have to slash the 22 bits from default 32 bits, remaining 10 bits. Now put those 10 bits in formula. 2^n -2 + 2.00 ^ 10.00 --------------- + 1,024.00 - 2.00 --------------- 1,022.00 So, you will have 1022 IP address in /22 Subnet. why you are subtracting 2 ? Link to comment Share on other sites More sharing options...
Xahid Posted June 21, 2017 Share Posted June 21, 2017 4 minutes ago, Deep_Level_Shark said: why you are subtracting 2 ? That's why I said, you need basic knowledge, anyways, its formula (which I am not going to explain) but to answer your question, Why subtracting 2 (IP's) 2 IPs will be used for broadcast, The 1st IP will be X.Y.Z.00000000 2nd IP will be X.Y.Z.11111111 T3X4S 1 Share Link to comment Share on other sites More sharing options...
Deep_Level_Shark Posted June 21, 2017 Author Share Posted June 21, 2017 (edited) 3 minutes ago, Xahid said: That's why I said, you need basic knowledge, anyways, its formula (which I am not going to explain) but to answer your question, Why subtracting 2 (IP's) 2 IPs will be used for broadcast, The 1st IP will be X.Y.Z.00000000 2nd IP will be X.Y.Z.11111111 I understand you meant first and last ip is reserved.....others can be allocated to hosts. Is it possible that in a subnetwork some more IPs are reserved not just 2 ? Link to comment Share on other sites More sharing options...
Xahid Posted June 21, 2017 Share Posted June 21, 2017 11 minutes ago, Deep_Level_Shark said: I understand you meant first and last ip is reserved.....others can be allocated to hosts. Is it possible that in a subnetwork some more IPs are reserved not just 2 ? Those are not reserved IP's, those IP's are broadcast IP's. what do you mean by reserved? Link to comment Share on other sites More sharing options...
+BudMan MVC Posted June 21, 2017 MVC Share Posted June 21, 2017 57 minutes ago, Xahid said: 2 IPs will be used for broadcast, Huh? There are not 2 broadcast IPs.. 1 IP is the wire, the other is the broadcast, this is why their are 2 removed. You can find a good cheatsheet here http://packetlife.net/library/cheat-sheets/ I have a few of them pinned up at work Mando and Xahid 1 1 Share Link to comment Share on other sites More sharing options...
T3X4S Posted June 21, 2017 Share Posted June 21, 2017 @OP Hop on YouTube - watch Eli the Computer Guy this one is about your topic I dont know if he still does vids, but whenever I needed a quick, clear explanation in layman's terms about some basic networking stuff in the past, I found his vids were always helpful. FWIW - Microsoft's Virtual Academy is good, but I find there is too much BS - I want the meat & potatoes version.Also, so many of the videos on MS's site, and the ones on YT are done by people where English is their 2nd or 3rd language - EXTREMELY frustrating when you are trying to learn something and you can't tell what they are saying. Link to comment Share on other sites More sharing options...
Skiver Veteran Posted June 21, 2017 Veteran Share Posted June 21, 2017 If you just want to skip to the easy way, cheat sheets FTW https://www.aelius.com/njh/subnet_sheet.html Link to comment Share on other sites More sharing options...
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