Week 6 Notes - WanderlustPenguin/Charles-Tech-Journal GitHub Wiki
Lectures
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subnetting: taking one network address and splitting it into smaller subnetworks
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MAC address: layer 2, 8 bit, hexadecimal
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IP address: layer 3, 32 bit, binary, contains the Network ID and the Host ID
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Network ID covers from 8 to 30 bits, Host ID is however many bits are left over. Network is 1 and host is 0 in binary in subnet mask
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255.255.255.0 is /24, and takes up 24 bits since each decimal area is worth 8 bits, written 11111111.11111111.11111111.00000000 in binary
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255.255.240.0 is /20, and takes up 20 bits
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255.255.252.0 is /22, and takes up 22 bits, written 11111111.11111111.11111100.00000000 in binary
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number of Usable IPs is total IPs-2. first non usable is the .0 value used for broadcasting, and the other is the network at .255
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decimal to binary: add up the part of the pattern the 1 is. above is large numbers, below are 1s and 0s, add the large number value of the one. large values work on power of 2, with the furthest right number being 2^0, and then moving 2^1,2^2 and so on
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Supernet/Supernetwork: CIDR block
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CIDR/supernetworking:classless interdomain routing, intended to allow full utilization of otherwise used IP space
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wasteless IPs are classless
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usable addresses can be found with 2^(32-/xx)
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subnet mask tells us how many bits are reserved for the network, and how many are allowed for the host
Labs
- DECBIN2 in excel converts the IP into binary if done individually for each decimal area
- Same applies to netmask
- The net mask is determined by doubling the amount subtracted for each layer down from a .255, i.e. -1,-2,-4,-8
- the .255 /xx are the multiples of 8, with /8 being .255.000.000.000, and /32 being .255.255.255.255
- Packet tracer automatically gives a subnet mask, it's always a single default, which is sometimes wrong
- default gateway is just the network