Short Notes: IPv4 / IPv6 | Short Notes for Computer Science Engineering - Computer Science Engineering (CSE) PDF Download

 Page 1


Internet Protocol
It is a set of technical rules that defines how computers communicate over a 
network.
IPv4
It is the first version of Internet Protocol to be
widely used, and accounts for most of today’s Internet traffic.
• Address Size: 32 bits
• Address Format: Dotted Decimal Notation: 192.149.252.76
• Number of Addresses: 232 = 4,294,967,296 Approximately
• IPv4 header has 20 bytes
• IPv4 header has many fields (13 fields)
• It is subdivided into classes <A-E>.
• Address uses a subnet mask.
• IPv4 has lack of security.
IPv4:
• Source and destination addresses are 32 bits (4 bytes) in length.
• IPsec support is optional
• Identification of packet flow for QoS handling by routers is absent within the 
IPv4 header.
• Fragmentation is performed by both routers and the sending host.
• Header includes a checksum.
• Header includes options.
Page 2


Internet Protocol
It is a set of technical rules that defines how computers communicate over a 
network.
IPv4
It is the first version of Internet Protocol to be
widely used, and accounts for most of today’s Internet traffic.
• Address Size: 32 bits
• Address Format: Dotted Decimal Notation: 192.149.252.76
• Number of Addresses: 232 = 4,294,967,296 Approximately
• IPv4 header has 20 bytes
• IPv4 header has many fields (13 fields)
• It is subdivided into classes <A-E>.
• Address uses a subnet mask.
• IPv4 has lack of security.
IPv4:
• Source and destination addresses are 32 bits (4 bytes) in length.
• IPsec support is optional
• Identification of packet flow for QoS handling by routers is absent within the 
IPv4 header.
• Fragmentation is performed by both routers and the sending host.
• Header includes a checksum.
• Header includes options.
• Address Resolution Protocol (ARP) uses broadcast ARP request frames to 
resolve an IPv4 address to a link layer address.
• Internet Group Management Protocol (IGMP) is used to manage local subnet 
group membership.
• ICMP router discovery is used to determine the IPv4 address of the best 
default gateway and is optional.
• Broadcast addresses are used to send traffic to all nodes on a subnet.
• Must be configured either manually or through DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv4 addresses.
• Uses pointer resource records in the INADDR, ARPA DNS domain to map IPv4 
addresses to host names.
• Must support a 576 byte packet size (possibly fragmented).
Figure 4.6. IPv4 H eader Format
IPv6: It is a newer numbering system that provides a much larger address pool than 
IPv4.
• Address Size: 128 bits
• Address Format: Hexadecimal Notation: 3FFE:F200:0234:AB00: 
0123:4567:8901 :ABCD
• Number of Addresses: 2128
• IPv6 header is the double, it has 40 bytes
• IPv6 header has fewer fields, it has 8 fields.
• It is classless.
• It uses a prefix and an Identifier ID known as IPv4 network
• It uses a prefix length.
• It has a built-in strong security (Encryption and Authentication)
Page 3


Internet Protocol
It is a set of technical rules that defines how computers communicate over a 
network.
IPv4
It is the first version of Internet Protocol to be
widely used, and accounts for most of today’s Internet traffic.
• Address Size: 32 bits
• Address Format: Dotted Decimal Notation: 192.149.252.76
• Number of Addresses: 232 = 4,294,967,296 Approximately
• IPv4 header has 20 bytes
• IPv4 header has many fields (13 fields)
• It is subdivided into classes <A-E>.
• Address uses a subnet mask.
• IPv4 has lack of security.
IPv4:
• Source and destination addresses are 32 bits (4 bytes) in length.
• IPsec support is optional
• Identification of packet flow for QoS handling by routers is absent within the 
IPv4 header.
• Fragmentation is performed by both routers and the sending host.
• Header includes a checksum.
• Header includes options.
• Address Resolution Protocol (ARP) uses broadcast ARP request frames to 
resolve an IPv4 address to a link layer address.
• Internet Group Management Protocol (IGMP) is used to manage local subnet 
group membership.
• ICMP router discovery is used to determine the IPv4 address of the best 
default gateway and is optional.
• Broadcast addresses are used to send traffic to all nodes on a subnet.
• Must be configured either manually or through DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv4 addresses.
• Uses pointer resource records in the INADDR, ARPA DNS domain to map IPv4 
addresses to host names.
• Must support a 576 byte packet size (possibly fragmented).
Figure 4.6. IPv4 H eader Format
IPv6: It is a newer numbering system that provides a much larger address pool than 
IPv4.
• Address Size: 128 bits
• Address Format: Hexadecimal Notation: 3FFE:F200:0234:AB00: 
0123:4567:8901 :ABCD
• Number of Addresses: 2128
• IPv6 header is the double, it has 40 bytes
• IPv6 header has fewer fields, it has 8 fields.
• It is classless.
• It uses a prefix and an Identifier ID known as IPv4 network
• It uses a prefix length.
• It has a built-in strong security (Encryption and Authentication)
32 bits
1
Version
’A )
Traffic Class (8) Flow Label (20)
Payload Length (16) Next Header (8) Hop Limit (B)
Source IP Address (128) 40 Bytes
Destination IP Address (128)
Transport Layer DBta (eg TCP, UDP)
IPv6:
• Source and destination addresses are 128 bits (16 bytes) in length.
• IPSec is mandatory and end to end.
• Packet flow identification for QoS handling by routers is included in the IPv6 
header using the flow label field.
• Fragmentation is not done by routers, only the sending host.
• Header does not include a checksum.
• All optional data is moved to IPv6 extension headers.
• ARP request frames are replaced with multicast neighbor solicitation 
messages.
• IGMP is replaced with Multicast Listener Discovery (MLD) messages.
• ICMP router Discovery is replaced with ICMPv6 Router solicitation and router 
advertisement messages and is required.
• There are no IPv6 broadcast addresses. Instead, a link local scope all nodes 
multicast address is used.
• Does not require manual configuration or DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv6 addresses.
• Uses pointer resource records in the IPv6 ARPA DNS domain to map IPv6 
addresses to host names.
• Must support a 1280 byte packet size ( without fragmentation)
Classes and Subnetting
There are currently five different field length pattern in use, each defining a class of 
address.
An IP address is 32 bit long. One portion of the address indicates a network (Net 
ID) and the other portion indicates the host (or router) on the network (i.e., Host 
ID).
To reach a host on the Internet, we must first reach the network, using the first 
portion of the address (Net ID). Then, we must reach the host itself, using the 2nd 
portion (Host ID).
The further division a network into smaller networks called subnetworks.
Page 4


Internet Protocol
It is a set of technical rules that defines how computers communicate over a 
network.
IPv4
It is the first version of Internet Protocol to be
widely used, and accounts for most of today’s Internet traffic.
• Address Size: 32 bits
• Address Format: Dotted Decimal Notation: 192.149.252.76
• Number of Addresses: 232 = 4,294,967,296 Approximately
• IPv4 header has 20 bytes
• IPv4 header has many fields (13 fields)
• It is subdivided into classes <A-E>.
• Address uses a subnet mask.
• IPv4 has lack of security.
IPv4:
• Source and destination addresses are 32 bits (4 bytes) in length.
• IPsec support is optional
• Identification of packet flow for QoS handling by routers is absent within the 
IPv4 header.
• Fragmentation is performed by both routers and the sending host.
• Header includes a checksum.
• Header includes options.
• Address Resolution Protocol (ARP) uses broadcast ARP request frames to 
resolve an IPv4 address to a link layer address.
• Internet Group Management Protocol (IGMP) is used to manage local subnet 
group membership.
• ICMP router discovery is used to determine the IPv4 address of the best 
default gateway and is optional.
• Broadcast addresses are used to send traffic to all nodes on a subnet.
• Must be configured either manually or through DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv4 addresses.
• Uses pointer resource records in the INADDR, ARPA DNS domain to map IPv4 
addresses to host names.
• Must support a 576 byte packet size (possibly fragmented).
Figure 4.6. IPv4 H eader Format
IPv6: It is a newer numbering system that provides a much larger address pool than 
IPv4.
• Address Size: 128 bits
• Address Format: Hexadecimal Notation: 3FFE:F200:0234:AB00: 
0123:4567:8901 :ABCD
• Number of Addresses: 2128
• IPv6 header is the double, it has 40 bytes
• IPv6 header has fewer fields, it has 8 fields.
• It is classless.
• It uses a prefix and an Identifier ID known as IPv4 network
• It uses a prefix length.
• It has a built-in strong security (Encryption and Authentication)
32 bits
1
Version
’A )
Traffic Class (8) Flow Label (20)
Payload Length (16) Next Header (8) Hop Limit (B)
Source IP Address (128) 40 Bytes
Destination IP Address (128)
Transport Layer DBta (eg TCP, UDP)
IPv6:
• Source and destination addresses are 128 bits (16 bytes) in length.
• IPSec is mandatory and end to end.
• Packet flow identification for QoS handling by routers is included in the IPv6 
header using the flow label field.
• Fragmentation is not done by routers, only the sending host.
• Header does not include a checksum.
• All optional data is moved to IPv6 extension headers.
• ARP request frames are replaced with multicast neighbor solicitation 
messages.
• IGMP is replaced with Multicast Listener Discovery (MLD) messages.
• ICMP router Discovery is replaced with ICMPv6 Router solicitation and router 
advertisement messages and is required.
• There are no IPv6 broadcast addresses. Instead, a link local scope all nodes 
multicast address is used.
• Does not require manual configuration or DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv6 addresses.
• Uses pointer resource records in the IPv6 ARPA DNS domain to map IPv6 
addresses to host names.
• Must support a 1280 byte packet size ( without fragmentation)
Classes and Subnetting
There are currently five different field length pattern in use, each defining a class of 
address.
An IP address is 32 bit long. One portion of the address indicates a network (Net 
ID) and the other portion indicates the host (or router) on the network (i.e., Host 
ID).
To reach a host on the Internet, we must first reach the network, using the first 
portion of the address (Net ID). Then, we must reach the host itself, using the 2nd 
portion (Host ID).
The further division a network into smaller networks called subnetworks.
H— Bytel — H<— Byte2— — Byte3— h- < — Byte4— h
For Class A: First bit of Net ID should be 0 like in following pattern 
01111011.10001111 . 1111100.11001111
For Class B: First 2 bits of Net ID should be 1 and 0 respective, as in below 
pattern 10011101 . 10001111 .11111100.11001111 
For Class C: First 3 bits Net ID should be 1,1 and 0 respectively, as follows 
11011101 . 10001111 . 11111100.11001111 
For Class D: First 4 bits should be 1110 respectively, as in pattern 
11101011 . 10001111 . 11111100.11001111
For Class E: First 4 bits should be 1111 respectively, like 
11110101 . 10001111. 11111100.11001111
Class Ranges of Internet Address in Dotted Decimal Format
From
Class A
Class B
Class C
ClassD
Class E
0 -0 0 0
127 255 255 255
H— M *-H ost ID -H M— Host ID -H
Net ID Net Id
128 0 0-0 191-255255 255
M— *-H-Host ID -H -« — H-*— Host ID -H
Net ID Net Id
1 9 2 0 0 0 223 255 255 255
Net ID Net ID Host ID
2 2 4 0 0 0 239 0 0 0
?Group Address*! ? Group Address*
240 0 0 0 255 255 255 255
W— Undefined— H M— Undefined— H
Three Levels of Hierarchy: Adding subnetworks creates an intermediate level of 
hierarchy in the IP addressing system. Now, we have three levels: net ID; subnet ID 
and host ID. e.g.,
1 4 H 4 
w-Net Id-H
21
H
Subnet ID 
- Subnetwork > 
access 
141 14 2 21
Host ID 
# — Host— M
141 14 22-8 141 14 7 44
A network with two level of hierarchy (not subnetted)
Page 5


Internet Protocol
It is a set of technical rules that defines how computers communicate over a 
network.
IPv4
It is the first version of Internet Protocol to be
widely used, and accounts for most of today’s Internet traffic.
• Address Size: 32 bits
• Address Format: Dotted Decimal Notation: 192.149.252.76
• Number of Addresses: 232 = 4,294,967,296 Approximately
• IPv4 header has 20 bytes
• IPv4 header has many fields (13 fields)
• It is subdivided into classes <A-E>.
• Address uses a subnet mask.
• IPv4 has lack of security.
IPv4:
• Source and destination addresses are 32 bits (4 bytes) in length.
• IPsec support is optional
• Identification of packet flow for QoS handling by routers is absent within the 
IPv4 header.
• Fragmentation is performed by both routers and the sending host.
• Header includes a checksum.
• Header includes options.
• Address Resolution Protocol (ARP) uses broadcast ARP request frames to 
resolve an IPv4 address to a link layer address.
• Internet Group Management Protocol (IGMP) is used to manage local subnet 
group membership.
• ICMP router discovery is used to determine the IPv4 address of the best 
default gateway and is optional.
• Broadcast addresses are used to send traffic to all nodes on a subnet.
• Must be configured either manually or through DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv4 addresses.
• Uses pointer resource records in the INADDR, ARPA DNS domain to map IPv4 
addresses to host names.
• Must support a 576 byte packet size (possibly fragmented).
Figure 4.6. IPv4 H eader Format
IPv6: It is a newer numbering system that provides a much larger address pool than 
IPv4.
• Address Size: 128 bits
• Address Format: Hexadecimal Notation: 3FFE:F200:0234:AB00: 
0123:4567:8901 :ABCD
• Number of Addresses: 2128
• IPv6 header is the double, it has 40 bytes
• IPv6 header has fewer fields, it has 8 fields.
• It is classless.
• It uses a prefix and an Identifier ID known as IPv4 network
• It uses a prefix length.
• It has a built-in strong security (Encryption and Authentication)
32 bits
1
Version
’A )
Traffic Class (8) Flow Label (20)
Payload Length (16) Next Header (8) Hop Limit (B)
Source IP Address (128) 40 Bytes
Destination IP Address (128)
Transport Layer DBta (eg TCP, UDP)
IPv6:
• Source and destination addresses are 128 bits (16 bytes) in length.
• IPSec is mandatory and end to end.
• Packet flow identification for QoS handling by routers is included in the IPv6 
header using the flow label field.
• Fragmentation is not done by routers, only the sending host.
• Header does not include a checksum.
• All optional data is moved to IPv6 extension headers.
• ARP request frames are replaced with multicast neighbor solicitation 
messages.
• IGMP is replaced with Multicast Listener Discovery (MLD) messages.
• ICMP router Discovery is replaced with ICMPv6 Router solicitation and router 
advertisement messages and is required.
• There are no IPv6 broadcast addresses. Instead, a link local scope all nodes 
multicast address is used.
• Does not require manual configuration or DHCP.
• Uses host address resource records in the Domain Name System to map host 
names to IPv6 addresses.
• Uses pointer resource records in the IPv6 ARPA DNS domain to map IPv6 
addresses to host names.
• Must support a 1280 byte packet size ( without fragmentation)
Classes and Subnetting
There are currently five different field length pattern in use, each defining a class of 
address.
An IP address is 32 bit long. One portion of the address indicates a network (Net 
ID) and the other portion indicates the host (or router) on the network (i.e., Host 
ID).
To reach a host on the Internet, we must first reach the network, using the first 
portion of the address (Net ID). Then, we must reach the host itself, using the 2nd 
portion (Host ID).
The further division a network into smaller networks called subnetworks.
H— Bytel — H<— Byte2— — Byte3— h- < — Byte4— h
For Class A: First bit of Net ID should be 0 like in following pattern 
01111011.10001111 . 1111100.11001111
For Class B: First 2 bits of Net ID should be 1 and 0 respective, as in below 
pattern 10011101 . 10001111 .11111100.11001111 
For Class C: First 3 bits Net ID should be 1,1 and 0 respectively, as follows 
11011101 . 10001111 . 11111100.11001111 
For Class D: First 4 bits should be 1110 respectively, as in pattern 
11101011 . 10001111 . 11111100.11001111
For Class E: First 4 bits should be 1111 respectively, like 
11110101 . 10001111. 11111100.11001111
Class Ranges of Internet Address in Dotted Decimal Format
From
Class A
Class B
Class C
ClassD
Class E
0 -0 0 0
127 255 255 255
H— M *-H ost ID -H M— Host ID -H
Net ID Net Id
128 0 0-0 191-255255 255
M— *-H-Host ID -H -« — H-*— Host ID -H
Net ID Net Id
1 9 2 0 0 0 223 255 255 255
Net ID Net ID Host ID
2 2 4 0 0 0 239 0 0 0
?Group Address*! ? Group Address*
240 0 0 0 255 255 255 255
W— Undefined— H M— Undefined— H
Three Levels of Hierarchy: Adding subnetworks creates an intermediate level of 
hierarchy in the IP addressing system. Now, we have three levels: net ID; subnet ID 
and host ID. e.g.,
1 4 H 4 
w-Net Id-H
21
H
Subnet ID 
- Subnetwork > 
access 
141 14 2 21
Host ID 
# — Host— M
141 14 22-8 141 14 7 44
A network with two level of hierarchy (not subnetted)
A network with three level ot hierarchy (subnetted)
Masking
Masking is process that extracts the address of the physical network form an IP 
address. Masking can be done whether we have subnetting or not. If we have not 
subnetted the network, masking extracts the network address form an IP address. 
If we have subnetted, masking extracts the subnetwork address form an IP 
address.
Masks without Subnetting: To be compatible, routers use mask even, if there is no 
subneting.
141 14 2 2 1 M ask 141 14 0 0
IP address 255 25 5 0 0
Network address "
Masks with Subnetting: When there is subnetting, the masks can vary
141 1 4 2 2 1 t
Mask 1 4 1 -1 4 2 0
IP address 2 5 5 2 5 5 2 5 5 0
Network address '
Masks for Unsubnetted Networks
Class Mask Address Netw ork
A 255.0.0.0 15.32.56.7 15.0.0.0
B 255.255.0.0 135.67.13.9 135.67.0.0
C 255.255.255.0 301.34.12.72 201.34.12.0
D N/A N/A N/A
E N/A N/A N/A
Masks for Subnetted Networks
C la ss M a s k
A d d r e s s
(E x a m p le )
N e t w o r k
A d d r e s s
A 2 5 5 .2 5 5 .0 .0 1 5 .3 2 .5 6 7 1 5 .3 2 .0 .0
B 2 5 5 .2 5 5 .2 5 5 .0 1 3 5 .6 7 .1 3 .9 1 3 5 .6 7 .1 3 .0
C 2 5 5 .2 5 5 .2 5 5 .1 9 2 2 0 1 .3 4 .1 2 .7 2 2 0 1 .3 4 .1 2 .0
D N /A N /A N /A
E N /A N /A N /A
Types of Masking
There are two types of masking as given below