Thirapon Wongsaardsakul Adapted from CISCO CCNAtulip.bu.ac.th/~thirapon.w/gim/ICN_files/Internet...Classify and Define IPv4 Addresses Name the three types of addresses in the network

Thirapon Wongsaardsakul

Adapted from CISCO CCNA

Internet Addressing

Objective Explain the structure IP addressing and demonstrate the ability to convert

between 8-bit binary and decimal numbers.

Given an IPv4 address, classify by type and describe how it is used in the network.

Explain how addresses are assigned to networks by ISPs and within networks by administrators.

Determine the network portion of the host address and explain the role of the subnet mask in dividing networks.

Given IPv4 addressing information and design criteria, calculate the appropriate addressing components.

Use common testing utilities to verify and test network connectivity and operational status of the IP protocol stack on a host.

IP Addressing Structure

IP Addressing Structure Describe the general role of 8-bit binary in network addressing

and convert 8-bit binary to decimal

IP Addressing Structure Practice converting 8-bit binary to decimal

Decimal Value 128 64 32 16 8 4 2 1

Octet Value X X X X X X X X

Decimal Value 128 64 32 16 8 4 2 1

Octet Value 1 1 0 0 0 0 0 1

128 + 64 + 1 = 193

6.1.3 activity

IP Addressing Structure Practice converting decimal to 8-bit binary

6.1.5 activity

Hand-on

Convert this dotted decimal to binary format

203.158.231.15

Classify and Define IPv4 Addresses Name the three types of addresses in the network and describe

the purpose of each type

Network Prefixes

• How do you know the number of bits assigned to the network and the number of bits

assigned to the host?

Prefix Mask:

The address is followed by a number that represents the number of bits (prefix

length), beginning from the left, that apply to the network.

A slash (/) is used to separate the address and the prefix length.

192.168.10.2/24

Means that the first 24 bits are the network portion.

The last 8 bits are the host portion.

Network Prefixes

• Networks are not always assigned a /24 prefix.

Depending on the number of hosts on the network, the prefix can be

different.

Having a different prefix changes the host range and the broadcast

address.

172.16.4.255 172.16.4.1 – 172.16.4.254 172.16.4.0 172.16.4.0/24

Broadcast

Address

Host Range

Network

Address

Network

172.16.4.127 172.16.4.1 – 172.16.4.126 172.16.4.0 172.16.4.0/25

172.16.4.63 172.16.4.1 – 172.16.4.62 172.16.4.0 172.16.4.0/26

172.16.4.31 172.16.4.1 – 172.16.4.30 172.16.4.0 172.16.4.0/27

Example of network and host

Classify and Define IPv4 Addresses Determine the network, broadcast and host addresses for a

given address and prefix combination

6.2.2 activity

Classify and Define IPv4 Addresses Name the three types of communication in the Network Layer

and describe the characteristics of each type

6.2.3 must see

Unicast Communications

• The process of sending a packet from one host to an individual host.

Special Unicast Addresses

• Default Route:

Address - 0.0.0.0 Subnet Mask – 0.0.0.0

When configured, it tells the device….

If you don’t know where to send the frame, send it here.


• Loopback:

Address - 127.0.0.1

Host applications use it to communicate with each other.

Test TCP/IP configuration on a PC – ping 127.0.0.1


• Link Local Addresses:

Address Range 169.254.0.0 to 169.254.255.255

Can be automatically assigned by the operating system where no IP

configuration is available.


• Test-Net Addresses:

Address Range 192.0.2.0 to 192.0.2.255

Used for teaching and learning purposes.

Appear in documentation and network examples.

Will be accepted by a network device.

Used to provide examples in RFCs and vendor and protocol documentation.

Should not appear on the Internet.

Your best bet…..

STAY AWAY FROM THEM….


• Experimental Address Range:

Address Range 240.0.0.0 to 255.255.255.254

Reserved for future use.

Cannot be used on IPv4 networks.

Used for research and experimentation.


• Public and Private Addresses:

Most IPv4 addresses are public addresses.

A public address is one that is designated for use in networks that are accessible on

the Internet.

Networks that require limited or no Internet access, use private

addresses.

Private addresses are assigned from blocks of private address space set aside for that

purpose.

10.0.0.0/8 (10.0.0.0 to 10.255.255.255)

172.16.0.0/12 (172.16.0.0 to 172.31.255.255)

192.168.0.0/16 (192.168.0.0 to 192.168.255.255)

Broadcast Communications

• The process of sending a packet from one host to all hosts in the

network.

Broadcast Communications

• Broadcasts are not forwarded by a router unless specifically

configured to do so.

• The bits in the host portion of a broadcast address will be

all 1s.

Multicast Communications

• The process of sending a packet from one host to a selected group of

hosts.


• Multicasting involves the use of a reserved network of IP Addresses (224.0.0.0).

• Each host that is to participate in a multicast session first joins the multicast group controlled by the router.

• When the packet from the source arrives at the router, it is forwarded to all members of the multicast group.


• The reserved multicast network or specific multicast addresses will be

displayed in the routing table of a device.

• The following is from a PC.

Packet tracer activity

Open the course web site.

Do unicasts, broadcasts, and multicasts activity

Classify and Define IPv4 Addresses Identify the address ranges reserved for these special purposes

in the IPv4 protocol

Classify and Define IPv4 Addresses Define public address and private address

10.0.0.0 to 10.255.255.255 (10.0.0.0 /8)

172.16.0.0 to 172.31.255.255 (172.16.0.0 /12)

192.168.0.0 to 192.168.255.255 (192.168.0.0 /16)

Public and private address activity

Drag and drop activity 6.2.5

Identify given IP addresses to a correct category

Classify and Define IPv4 Addresses

Identify the historic method for assigning addresses and the

issues associated with the method

Addressing the Network: IPv4

Legacy IPv4 Addressing

Legacy IPv4 Addressing

• In the early 1980’s, unicast address ranges were grouped into specific

sizes or classes of address.

• Each class defined:

A specifically sized network.

Specific address blocks for these networks.

Class

High

Order

Bits

First Octet

Range

Number of

Network

Bits

Number

of Host

Bits

Number of

Networks

Number of

Hosts per

Network

A 0 0-127 8 24 128 16,777,216

B 10 128-191 16 16 16,384 65,536

C 110 192-223 24 8 2,097,152 256

D 1110 224-239 Used for Multicasting to multiple hosts.

E 1111 240-255 Reserved for research and development.

IPv4 Classful Addressing

• Devices examined the first octet of the address and could determine

the address range.

• The high order bits never change for each class.

Classful Addressing:

192.168.23.2 is in the Class C range

Therefore – 24 network bits and 8 hosts bits.

Class

High

Order

Bits

First

Octet

Range

Number

of Network

Bits

Number

of Host

Bits

Number

of

Networks

Number

of Hosts

per Network

A 0 0-127 8 24 128 16,777,216

B 10 128-191 16 16 16,384 65,536

C 110 192-223 24 8 2,097,152 256


• In a classful addressing scheme, these divisions take place at the octet

boundaries.

This may seem obvious now but is important to remember when we

explore how to divide a single network into several smaller subnets

(subnetting).

Class

High

Order

Bits

First

Octet

Range

Number

of Network

Bits

Number

of Host

Bits

Number

of

Networks

Number

of Hosts

per Network

A 0 0-127 8 24 128 16,777,216

B 10 128-191 16 16 16,384 65,536

C 110 192-223 24 8 2,097,152 256


• In the early 1990s, the subnet mask was added to IPv4.

The subnet mask allowed networks to subdivided or subnetted.

Each class was assigned a default subnet mask.

Class

First

Octet

Range

Number

of Network

Bits

Number

of Host

Bits

Default

Subnet

Mask

Number

of

Networks

Number

of Hosts

per Network

A 0-127 8 24 255.0.0.0 128 16,777,216

B 128-191 16 16 255.255.0.0 16,384 65,536

C 192-223 24 8 255.255.255.0 2,097,152 256

IPv4 Classful Addressing • Let’s quickly review….

In order to function properly with network devices, every IP network must contain three types of addresses:

Network Address:

o All HOST BITS are set to 0.

Host Address: HOST BITS will vary.

Broadcast Address:

o All HOST BITS are set to 1.

For a host to communicate directly with another host on the same network, they must have the same network portion.

IPv4 Classful Addressing • SO:

For every IP address range that we assign to a network segment, we

automatically lose two addresses….

One for the network address (sometimes called the wire address or subnetwork

address)

One for the broadcast address for that network.


• Our numbers for the number of hosts per network have to change to allow for the special use of the network number and broadcast addresses.

• As we will see, the formula (2number_of_bits - 2 or 2n - 2) is an important part of assigning an IP address range to a network segment.

Class

Number of

Network

Bits

Number

of Host

Bits

Number Hosts Per

Network Number of Useable Hosts per Network

A 8 24 224 = 16,777,216 224 - 2 = 16,777,214

B 16 16 216 = 65,536 216 - 2 = 65,534

C 24 8 28 = 256 28 - 2 = 254

IPv4 Classless Addressing • The system currently in use is classless addressing.

Address blocks appropriate to the number of hosts are assigned to

companies or organizations without regard to the class.

This is accomplished by subnetting with

Variable Length Subnet Masking (VLSM).

To understand classless addressing, you must first understand classful addressing.

Determine the network portion of the host

address and the role of the subnet mask

Describe how the subnet mask is used to create and specify the

network and host portions of an IP address

Determine the network portion of the host address

and the role of the subnet mask

Use the subnet mask and ANDing process to extract the

network address from the IP address

Finding network address

address

172.16.20.35

10101100.00010000.00010100.00100011

subnet mask

255.255.255.224

11111111.11111111.11111111.11100000

network address

172.16.20.32

10101100.00010000.00010100.00100000

00000000 = 0

10000000 = 128

11000000 = 192

11100000 = 224

11110000 = 240

11111000 = 248

11111100 = 252

11111110 = 254

11111111 = 255

Do activity

6.5.4 finding network address

6.5.5 finding number of host

6.5.6 fining all

Calculating Addresses Use the subnet mask to divide a network into smaller

networks and describe the implications of dividing networks

for network planners

Calculating Addresses

Calculating Addresses

Calculating Addresses Extract network addresses from host addresses using the

subnet mask

Variable Length Subnet Masking

(VLSM) A serious limitation of using only a single subnet mask across a given

network-prefix (the number of network or 1 bits in the mask) was that an organization is locked into a fixed-number of fixed-sized subnets.

VLSM enables a network number to be configured with different subnet masks on different interfaces. Subnet an already subnetted network address. Conserves IP addresses. More efficient use of available address space.

Allows for more hierarchical levels within an addressing plan.

10.2.0.0/24 10.2.0.1 10.2.0.254 10.2.0.255

Sub-subnet 10.2.1.0/24 10.2.1.1 10.2.1.254 10.2.1.255

Using /24 10.2.2.0/24 10.2.2.1 10.2.2.254 10.2.2.255

Etc.

10.2.255.0/24 10.2.255.1 10.2.255.254 10.2.255.255

Variable Length Subnet Masking (VLSM)

10.0.0.0/8 Subnet using /16

Subnet 1st Host Last Host Broadcast

10.0.0.0/16 10.0.0.1 10.0.255.254 10.0.255.255

10.1.0.0/16 10.1.0.1 10.1.255.254 10.1.255.255

10.2.0.0/16 10.2.0.1 10.2.255.254 10.2.255.255

10.3.0.0/16 10.3.0.1 10.3.255.254 10.3.255.255

Etc.

10.255.0.0/16 10.255.0.1 10.255.255.254 10.255.255.255

Subnet 1st Host Last Host Broadcast


(VLSM)

192.168.20.0/27

192.168.20.32/27 192.168.20.96/27 192.168.20.64/27

192.168.20.64/27

192.168.20.128/27

192.168.20.128/27

7 Networks with 30 usable

addresses for each network

Wasted 28 addresses on each

WAN link


(VLSM)

192.168.20.0/27

192.168.20.192/30 192.168.20.196/30 192.168.20.200/30

192.168.20.32/27

192.168.20.64/27

192.168.20.96/27

1 1 0 0 0 0 0 0 192.168.20.192

1 1 0 0 0 1 0 0 192.168.20.196

1 1 0 0 1 0 0 0 192.168.20.200

1 1 0 0 1 1 0 0 192.168.20.204

1 1 0 1 0 0 0 0 192.168.20.208

1 1 0 1 0 1 0 0 192.168.20.212

1 1 0 1 1 0 0 0 192.168.20.216

1 1 0 1 1 1 0 0 192.168.20.220

255.255.255.252 Sub-Subnet

Mask

Magic Number

= ? 1 1 1 1 1 1 0 0

Variable Length Subnet Masking (VLSM)

Original

Subnet Mask

Magic Number

= 32

255.255.255.224

1 1 1 0 0 0 0 0

192.168.20.0 0 0 0 0 0 0 0 0

192.168.20.32 0 0 1 0 0 0 0 0

192.168.20.64 0 1 0 0 0 0 0 0

192.168.20.96 0 1 1 0 0 0 0 0

192.168.20.128 1 0 0 0 0 0 0 0

192.168.20.160 1 0 1 0 0 0 0 0

192.168.20.192 1 1 0 0 0 0 0 0

192.168.20.224 1 1 1 0 0 0 0 0

Testing the Network Layer

Describe the general purpose of the ping command, trace the

steps of its operation in a network, and use the ping command

to determine if the IP protocol is operational on a local host

Testing the Network Layer Use ping to verify that a local host can communicate with a

gateway across a local area network

Testing the Network Layer Use ping to verify that a local host can communicate via a

gateway to a device in remote network

Testing the Network Layer Use tracert/traceroute to observe the path between two

devices as they communicate and trace the steps of

tracert/traceroute's operation

Testing the Network Layer Describe the role of ICMP in the TCP/IP suite and its impact

on the IP protocol

Documents

Thirapon Wongsaardsakul Adapted from CISCO CCNAtulip.bu.ac.th/~thirapon.w/gim/ICN_files/Internet...Classify and Define IPv4 Addresses Name the three types of addresses in the network