Networking (Tutorial-9) TCP/IP Fundamental

TCP/IP Fundamental

TCP/IP Suites

• The TCP/IP Protocol Suite

The TCP/IP protocol suite, also referred to as the Internet protocol suite, is the set of communications protocols that implements the protocol stack on which the Internet and most commercial networks run. It is named after the two most important protocols in the suite: the Transmission Control Protocol (TCP) and the Internet Protocol (IP).

TCP/IP Protocol

IP Address

• Internet Protocol Address is given to the computer as an identifier to a computer in a TCP/IP Network 
• IP Address is also known as Logical Address 
• IP Address works in Layer 3 (Network)‏ 
• Two versions of IP Addressing 
• IP Version 4 - 32 bit address (used currently) 
• IP Version 6 - 128 bit address 
• To make it easier to work with these addresses, the 32-bit binary number is broken into a series of decimal numbers. 
• To do this, split the binary number into four groups of eight binary digits. 
• Then convert each group of eight bits, also known as an octet into its decimal equivalent. 

Parts of an IP Address

Just as a street address has a standard two-part format (a street name and a house number), each IP address is separated internally into two parts—a network ID and a host ID.

Network ID:

• The network ID, also known as a network address, identifies a single network segment within a larger internetwork 
• All the systems that attach and share access to the same network have a common network ID within their full IP address. 
• This ID is also used to uniquely identify each network within the larger internetwork 

Host ID:

• The host ID, also known as a host address, identifies a node within each network. 
• The host ID for each device identifies a single system uniquely within its own network.

Classification of IP addresses

IP Address is classified into three classes as follows

• Class A is written as N.H.H.H 
• Class B is written as N.N.H.H 
• Class C is written as N.N.N.H

Subnet Mask

• A ‘subnet’ is a portion of the computer network that shares a common address component 
• Dividing a network into subnets is useful for both performance and security reasons 
• A ‘subnet mask’ is used to determine what subnet an IP address belongs to
• Subnet Mask is to differentiate the Network ID and Host ID 
• Two numbers reserved for Subnet Mask i.e. 0 & 255 
• 0 Denotes Host and 255 Denotes Network 

                              

IP Address : 10.20.50.26 Subnet Mask : 255.0.0.0

For this IP Address :

• Network ID is : 10.0.0.0
• First Valid IP Address : 10.0.0.1 
• Last Valid IP Address : 10.255.255.254
• Broad Cast Address : 10.255.255.255
• Number of hosts = (256x256x256) -2

IP Address 172.26.28.36 Subnet Mask : 255.255.0.0

For this IP Address,

• Network ID is : 172.26.0.0 
• First Valid IP Address : 172.26.0.1 
• Last Valid IP Address : 172.26.255.254 
• Broad Cast Address : 172.26.255.255 
• Number of hosts =(256x256) – 2 

IP Address 192.168.0.152 Subnet Mask 255.255.255.0

For this IP Address:

• Network ID is : 192.168.0.0
• First Valid IP Address : 192.168.0.1
• Last Valid IP Address : 192.168.0.254
• Broad Cast Address : 192.168.0.255 
• Number of hosts = (256) – 2 

Classification of IP addresses

IP addresses can be -

• Private – A set of IP addresses reserved by the Internet Standards group for private usage. It provides high security to the network. 
• Public -All the other IP addresses come under Public IP addresses, which can be easily accessed by everyone. 
• Static-An IP address that remains the same every time the computer logs on to the Internet. 
• Dynamic –Is assigned to a computer every time it connects to the Internet and is different every time. 

Private IP Address

• IP addresses are publicly registered with the Network Information Centre (NIC) to avoid address conflicts 
• Computers on private TCP/IP LANs however do not need public addresses 
• For this reason, the NIC has reserved certain addresses that will never be registered publicly. These are known as private IP addresses 
• The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP 

Private IP Address Range:

Internet Control Message Protocol

• ICMP is implemented on all TCP/IP networks, providing messaging that can help with troubleshooting, including 

1. Destination unreachable 
2. Time exceeded 
3. Redirect 
4. Echo 
5. Echo reply 
6. Information request 
7. Information reply 
8. Address mask request 

MAC Address

• The Media Access Control address (MAC) can be equated to the serial number of the NIC. Every IP packet is sent out of your NIC wrapped inside an Ethernet frame which uses MAC addresses to direct traffic on your locally attached network 
• MAC addresses therefore only have significance on the locally attached network. As the packet hops across the Internet, its source/destination IP address stays the same, but the MAC addresses are reassigned by each router on the way using a process called ARP
• MAC addresses are usually written in one of the following two formats:

                      00:13:21:0F:83:DF 00-13-21-0F-83-DF

• MAC address is a 48 bit address
• MAC address are 12 digit Hexadecimal {0-9} {A- F} Address
• The First Octet of the MAC Address is known as Group Unique - 

                       00 : 13 : 21 : 0F : 83 : DF

• The Second and Third Octet of the MAC Address is known as Organization Unique Identifier (OUI)                    

                      00 : 13 : 21 : 0F : 83 : DF

• Any MAC address starts with 00 is known as Unicast address 

                      00 : 13 : 21 : 0F : 83 : DF

• Any MAC address starts with 01 is known as Multicast 

                      01 : 13 : 21 : 0F : 83 : DF

• Any MAC address starts with FF is known as Broadcast

                     FF : 13 : 21 : 0F : 83 : DF