From the course: Networking Foundations: IP Addressing

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Solution: Subnet masks

Solution: Subnet masks

From the course: Networking Foundations: IP Addressing

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Solution: Subnet masks

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(upbeat music) - [Instructor] Well how did you do with this challenge regarding subnet masks? Let's take a look at the solutions. What is the default subnet mask for the Class B address space? Well we remember in the Class B it's 16 bits, so that's 255.255.0.0. What's the dotted decimal notation representation of the subnet mask in this example? And notice we have 172.16.1.0 and the prefix mask is slash 20 so we know that that is eight bits plus eight bits plus four bits, 'cause eight plus eight plus four is going to equal 20. So if we do the four bits we have the 128 bit is on the 64 bit is on the 32 bit is on and the 16 bit is on and this gives us our value there in the third octet of 240. So slash 20 is 255.255.240.0. What is the default subnet mask used in IPv6 addressing? Well we know that's a slash 64 by default. And finally what two parts of the IP address does the subnet mask delineate? And of course the subnet…

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