CT320: Network and System Administration

Fall 2019

IQ 09

CT320 IQ 09

Show Main.IQ09 as a slide show.

Bits

An IP address has how many bits?

  1. 4
  2. 16
  3. 32
  4. 48
  5. 64
  6. It depends on how many bytes are in a bit.

32 bits, usually broken into 4 bytes: a.b.c.d

IP address

Each host on the internet has:

  1. No IP addresses
  2. Zero or one IP addresses
  3. Zero or more IP addresses
  4. One IP address
  5. One or more IP addresses
  6. Over four billion IP addresses

One or more. If it has none, it’s not “on” the internet. A router or gateway always has several: one for each side.

Address categories

  1. 10.2.1.20=CSU, 141.193.213.21=doc, 203.0.113.42=private
  2. 10.2.1.20=CSU, 141.193.213.21=private, 203.0.113.42=doc
  3. 10.2.1.20=doc, 141.193.213.20=CSU, 203.0.113.42=private
  4. 10.2.1.20=doc, 141.193.213.20=private, 203.0.113.42=CSU
  5. 10.2.1.20=private, 141.193.213.21=CSU, 203.0.113.42=doc
  6. 10.2.1.20=private, 141.193.213.20=doc, 203.0.113.42=CSU

CSU: 129.82/16; private: 10/8 (and others); documentation: 203.0.113.0/24 (and others)

Old-Style Address Class

Which old-style address class is 203.0.113.96?

  1. Class B
  2. Class D
  3. Class A
  4. Class E
  5. Class C
  • Class A: 128 possibilities for the first byte: 0/8 – 127/8
  • Class B: 64 possibilities for the first byte: 128/16 – 191/16
  • Class C: 32 possibilities for the first byte: 192/24 – 223/24

CIDR

A network consists of the 512 addresses 14.2.(0–1).(0–255). In CIDR notation, that is:

  1. 14.2.0/9
  2. 14.2.0/23
  3. 14.2.1/9
  4. 14.2.1/23
  5. 14.2.1.255/23

The /n refers to the size of the network field, on the left, not the size of the host field.

CIDR

How many hosts are possible for the network 10.0.0.0/10?

  1. about ten
  2. about a thousand
  3. about a million
  4. about four million
  5. one billion hosts!

The /10 refers to the size of the network. 10 bits for the network means 22 bits for the hosts. 222 ≈ 4 million.