Tag - IP Addressing

IP Addressing step by step

IPv4 addresses

  • Consist of 32 bits.
  • Are broken into four octets (8 bits each).
  • Use dotted-decimal format; an example is
  • Minimum value (per octet) is 0, and the maximum value is 255.
  • is a network ID.
  • is a broadcast IP.

IPv4 Address Classes

TABLE FF.13IPv4 Address Classes
First OctetSecond OctetThird OctetFourth Octet
Class ANetworkHostHostHost
Class BNetworkNetworkHostHost
Class CNetworkNetworkNetworkHost

TCP/IP defines two additional address classes:

  • Class D: Used for multicast addresses.
  • Class E: Used for research purposes.

ip address

TABLE FF.14 Address Class Ranges

Class                                    First Octet Decimal Range

A                                              1 to 126

B                                             128 to 191

C                                             192 to 223

D                                             224 to 239

E                                              240 to 255

The 127.x.x.x address range is reserved for loopback addresses.

Default subnet masks:

  • ¬†Class A:
  • Class B:
  • Class C:

Classless Addressing

Classless Interdomain Routing (CIDR) notation might also be used to identify the subnet mask. The CIDR notation for each network class can be determined by counting the 1s in binary or the number of bits that make up the network portion of the address.

The mask is written in slash notation as follows:

  • Class A: /8
  • Class B: /16
  • Class C: /24

Private Ranges

IANA private address space allocations:

  • Class A: to
  • Class B: to
  • Class C: to


TABLE FF.15 Decimal to Binary Conversions

ClassFirst Octet Decimal Range

To calculate the hosts in a subnet, we can use the formula 2H ‚Äď 2. The exponent H represents the number of host bits in a network.

To calculate the networks in a subnet, we can use the formula 2N ‚Äď 2. The exponent N repre¬≠sents the number of subnet bits in a network.

The range of valid IP addresses in a subnet is the first IP address after the Network ID and the last IP address before the broadcast IP address.

The following represents IP subnetting: IP address =

Subnet mask =

Network ID =

Broadcast IP =

Valid IP range = to


IPv6 is a workable IP version that was created in the event that the IP space from IPv4 is exhausted.

IPv6 address format summary:

  • Defined by RFC 2373 and RFC 237.
  • Consists of 128 bits, with a 64-bit network prefix and a 64-bit local identifier.
  • Represented by 32 hexadecimal digits broken into eight smaller groups of four.
  • Utilizes CIDR notation (slash notation) to discern a subnet range, so you might see the same IP address subnetted and written out as

2001 :0BD2:0200:08F1 :0000:0000:0000: 16AB/16.

The same IPv6 IP address can be written out in all of the following ways: 2001 :0BD2 :0200:08F1 :0000:0000:0000: 16AB

200 1:BD2 :200:8F1 :0:0:0:16AB

200 1:BD2 :200:8F1 ::16AB


Types of IPv6 Addresses

1. Link-local addresses: Addresses that have the shortest reach of the IP address types. They can only go as far as the Layer 2 domain. These addresses are autogenerated with or without the use of a DHCP server. So, when an IPv6 node goes online, this address is assigned automatically.

2. Unique/site-local addresses: Addresses that have a broader scope than link-local addresses. They can expand to the size of an organization and are used to describe the boundary of the organizational network. These are the private addresses for IPv6.

3.¬†Global addresses: Addresses that have the broadest scope of all. As the name indi¬≠cates, these addresses are for global use‚ÄĒthat is, for Internet communications.

4. Multicast: Addresses that are extremely important because of their use in group com­munications and broadcast messaging.

Integrating IPv4 and IPv6

There are several ways to integrate IPv4 and IPv6 addressing. You can implement dual-stack,tunneling, or translation techniques to help IPv4 and IPv6 addresses exist together on the net-work simultaneously.

CDP and IP Addressing LAB

Lab 2 ‚Äď CDP

You have just been asked to build a network map of your current network using CDP.
Use the common CDP commands to understand what type of devices you are working
with and how they are interconnected together. To complete this lab you will need to
connect to each device in the topology and enable each interface. After you have enabled
all interfaces use the command Show cdp neighbors detail.

The answer is the graphic at the top of the next lab.


Lab 3 ‚Äď IP Addressing


ip address lab ccna

You have just been asked to build a lab network to test new configurations that will be
rolled out to your production network. Host A (on the left) should be setup with an IP
address of /24 and a default gateway of Host B (on the
right) should be setup with an IP address of /24 and a default gateway of The Ethernet interface of Router1 (on the left) should use an IP address
of /24 and the Serial interface of Router1 should use an IP address of /24. The Ethernet interface of Router2 (on the right) should use an IP
address of /24 and the Serial interface of Router2 should use an IP address
of /24. You have a DCE cable connected to Router1. The serial link should
have speed of 64K. Configure the devices with hostnames and make sure that the can
ping any device that is directly connected. When you are finished with the lab select the
File->Save Network Configuration for use in the future labs.


hostname router1
interface Ethernet0
ip address
no shut
interface Serial0
ip address
clock rate 64000
no shut

hostname router2
interface Ethernet0
ip address
no shut
interface Serial0
ip address
no shut

Host A:
Ipconfig /IP
Ipconfig /DG

Host B:
Ipconfig /IP
Ipconfig /DG



CCNA Labs Scenario

Scenario Labs For CCNA

  1. Setting up a Serial Interface 
  2. CDP
  3. IP Addressing
  4. Static Routes
  5. Default Routes
  6. RIP Routes
  7. IGRP Routes
  8. Using Loopback Interfaces
  9. RIP v2 Routes
  10. CHAP and RIP
  11. Standard Access-Lists with RIP
  12. Extended Access-Lists with RIP
  13. EIGRP Routes
  14. OSPF Routes
  15. Static NAT
  16. Many to One NAT
  17. NAT Pool
  18. Telnet
  19. 2950 IP Addresses
  20. 2950 Trunk
  21. 2950 Trunk (Dynamic)
  22. 2950 VLANs
  23. 2950 Deleting VLANs
  24. 2950 VTP
  25. 2950 VTP w/ client
  26. 2950 Telnet

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