Subnets

subnetting

breaking down larger networks ___ is a process of subdividing a single class of networks into multiple, smaller logical networks, or segments. -greater no of networks -simplify ip addressing - better security - smaller collision and broadcast domains -greater administration control of each network

Class B subnetting , finding hosts and subnets

https://www.youtube.com/watch?v=IWJiCXPt744&list=PL407F5B7860D15F18&index=18

Class C Subnetting finding hosts

https://www.youtube.com/watch?v=IWJiCXPt744&list=PL407F5B7860D15F18&index=18

Class C Subnetting

https://www.youtube.com/watch?v=dfArOHkAVbc

why subnetting

https://www.youtube.com/watch?v=o3I0CFgVzMw shortage of address soln - subnetting - NAT (Network Address Translation) -classless IP addressing

Which of the following is a correct form of CIDR notation?

192.168.1.0/24

What is the maximum valid range for IP addresses that can be assigned to hosts on the 192.168.100.248 255.255.255.248 network?

192.168.100.249 - 192.168.100.254

What is the network address for the 192.168.223.15 255.255.255.252 host?

192.168.223.12

What is the last usable host IP address on the 192.168.32.9/30 network?

192.168.32.10

Which of the following answers lists the broadcast address for the 192.168.50.155/20 network?

192.168.63.255

How many possible host IDs do you always lose per network?

2

CIDR Notation

*Without CIDR Notation* - 192.168.10.1 - 255.255.255.248 *With CIDR Notation* - 192.168.10.1/29

Number of Subnets Formula

- *2ⁿ* - *n = number of 1's in the Subnet ID*

Number of Available Host Addresses Formula

- *2ⁿ−2* - *n = number of 0's in the Host ID* - Host ID can't be all 0's or 1's

Example of Formulas

- 11111111.11111111.11111000.00000000 - 2⁵ = *32 Subnets* - 2¹¹−2 = *2046 Hosts* in each subnet

Subnetting a Network

- Borrow one Bit from the host portion of the large IP address - The bit your borrow is represented by the place holder for ex. 128, 64. 32, 16, 8, 4, 2, 1 - The subnet block size = the value of the place holder - The number of available host IP addresses is always two minus the block size (Network ID & Broadcast ID)

Subnetting

- Breaking down a large network - Treating the segments as separate networks - Classless IP addressing

Binary IP Addresses

- Each of the 4 numbers in an IP Address is called an *octet (8 bits)*.

Private IP address

- IP addresses that cannot travel across the internet - Can only travel across the LAN - Class A: 10.0.0.0 - 10.255.255.255 - Class B: 172.16.0.0 - 172.31.255.255 - Class C: 192.168.0.0 - 192.168.255.255

Routers & LAN Devices

- ISP assigns a public IPv4 address (internet facing) to a router - The Router assigns private IP address to devices inside of the LAN

What is the last usable host IP address for the 172.45.120.0/23 network?

172.45.121.254

class B IP address

-16 bits for network address and 16 bits for hosts -a balance between number of networks and hosts -begins with 10 (1st zero in second position ) -14 remaining bits in network - 16 bits in local part 128.0.0.00 to 191.255.255.255 -exceptions in class B IP address 169.254.x.x no of networks - 2^14 = 16384 no of addresses per network 2^16

class C IP address

-24 bits for network address and 8 bits for hosts -popularly and commonly used -begins with 110 (1st zero in third position) -21 bits left for network part (over 2 million) -8 bits in local part (only 256 ) -192.0.0.0 to 223.255.255.255 - no of networks - 2^21 = 2097152 -addresses per network - 2^8 = 256

Network mask

-32 bits - separated by dots like IPv4 address -This type of mask always begins with a series of 1's followed by a series of 0's. The bits in the network part of the mask are 1's, while the remaining bits are 0's. -A 32-bit binary mask that separates the network address from the host address in an IPv4 address -the mask indicates how many bits in the address represent the network prefix

Reserved addresses

-beginning 127 are reserved for loopback and internal testing -xxx.0.0.0 reserved for network address -xxx.255.255.255 reserved for broadcast for class a (e.g) - a class ip address - 101.101.101.101 -network address - 101.0.0.0 -broadcast network - 101.255.255.255

class A IP addresss

-begins with 0 -7 remaining bits in network part -24 bits in local part

classless ip address

-the network ID is not a multiple of an octet, and can range from 13 to 27 bits -IP addresses that use a custom subnet mask value to separate network and host portions of the IP address. -A convention for IP addresses in which class A, B, and C default network prefixes (of 8, 16, and 24 bits, respectively) are ignored.

What is the CIDR notation of the 255.192.0.0 subnet mask?

/10

What is the CIDR notation for 255.255.224.0 subnet mask?

/19

What is the CIDR notation of the 255.255.255.224 subnet mask?

/27

What is the first valid host address for a node residing in the 10.119.136.143/20 network?

10.119.128.1

What is the binary notation of the decimal number 252?

11111100

What is the binary representation of the 255.254.0.0 subnet mask?

11111111.11111110.00000000.00000000

What is the binary representation of the 255.255.128.0 subnet mask?

11111111.11111111.10000000.00000000

What is the leading octet value range for an IPv4 address belonging to a class B network?

128 - 191

What is the maximum valid range for IP addresses that can be assigned to hosts on the 134.170.185.46 255.255.128.0 network?

134.170.128.1 - 134.170.255.254

What is the network address for the 154.24.67.147/22 host?

154.24.64.0

APIPA `

169.254.x.x

What is the first usable host IP address on the 172.26.56.110/27 network?

172.26.56.97

What is the decimal notation of the binary number 11100000?

224

What is the dot-decimal representation of a /13 subnet mask?

255.248.0.0

How many octets does a subnet mask have?

4

What is the maximum number of hosts per subnet for the 10.47.255.1/20 network?

4094 hosts

What is the broadcast address for the 46.28.247.109/10 network?

46.63.255.255

How many usable IP addresses can be assigned to hosts on a /26 subnet?

62

What is the maximum number of subnets and hosts per subnet for the 192.168.50.247 255.255.255.224 network?

8 subnets, 30 hosts per subnet

VLSM (Variable Length Subnet Mask)

A classless subnet mask that can be customized to a different length for each subnet based on the number of nodes on that subnet

subnet mask

A subnet mask is a group of four numbers (dotted decimal numbers) that tell TCP/IP if a remote computer is on the same or a different network.

Public IP address

All IP addresses except those reserved for private IP addresses. An IP address available to the Internet. An IP address that is part of a registered network number, as assigned by an Internet Assigned Numbers Authority (IANA) member agency, so that only the organization to which the address is registered is allowed to use the address. Routers in the Internet should have routes allowing them to forward packets to all the publicly registered IP addresses. - class A begins with 1 to 126 - class B begins with 128 to 191 - class C begins with 192 to 223

Private IP address

An IP address that is used on a private TCP/IP network that is isolated from the Internet. -cannot go on the internet -10.0.0.0 to 10.255.255.255 (class A) -172.16.0.0 to 172.31.255.255 (class B) - 192.168.0.0 to 192.168.255.255 (class C)

In IPv4 addressing, the leading octet of an IP address with a value of 1 through 126 denotes that the IP address within that range belongs to the:

Class A address space

What refers to the characteristic features of the 10.0.0.0 - 10.255.255.255 IPv4 address space?

Class A range, Non-routable (private) IP address range

What refers the characteristic features of the 172.16.0.0 - 172.31.255.255 IPv4 address space?

Class B range, Non-routable (private) IP address range

In IPv4 addressing, the leading octet of an IP address with a value of 192 through 223 denotes that the IP address within that range belongs to the:

Class C address space

What refers to the characteristic features of the 192.168.0.0 - 192.168.255.255 IP address space?

Class C range, Non-routable (private) IP address range

What refers to the leading octet value range and class of the IPv4 multicast address block?

Class D, 224 - 239

What does CIDR stand for?

Classless Inter-Domain Routing

*Class A* IP Address

First Octet: *1-127* Subnet Mask: *255*.0.0.0 *126* Networks *16,777,214* Hosts

*Class B* IP Address

First Octet: *128-191* Subnet Mask: *255*.*255*.0.0 *16,384* Networks *65,534* Hosts

*Class C* IP Address

First Octet: *192-223* Subnet Mask: *255*.*255*.*255*.0 *2,097,152* Networks *254* Hosts

*Class D* IP Address

First Octet: *224-239* *Multicast*

*Class E* IP Address

First Octet: *240-243* *Experimental*

Subnetting w/ CIDR and VLSM

If we start with (B-Class network) 255.255.0.0, but we want to divide into smaller networks we need to *take bits from the Host ID* and *move them into the Network ID*.

Compared to the number of all IPv4 addresses available per subnet, the total number of usable IPv4 addresses that can be assigned to hosts from that pool is reduced by two. Those two addresses that cannot be assigned to hosts are used as:

Network and Broadcast address

Consider the following scenario: Your IP address is 192.168.8.34, and your subnet mask is 255.255.0.0. What part of the subnet mask represents the subnet ID?

The first two octets of the subnet mask, 255.255

Subnet Example

Original Network - *172.16.0.0* (65534 Hosts) Subnet Mask - *255.255.0.0* Subnet 1 - 172.16.*1*.0 (254 Hosts) Subnet 2 - 172.16.*2*.0 (254 Hosts) Subnet 3 - 172.16.*3*.0 (254 Hosts) Subnet Mask - *255.255.255.0*

Type of IP address

Private Public

Subnetting

The process of taking *a large network and dividing it into smaller networks* to increase efficiency and manageability.

Class B Subnetting Example

screenshot @ min mark on the super-subnetting vid

Class B Subnetting Example

screenshot @8:43 min mark on the super-subnetting vid