IPV4 & IPV6 Features

Author By: Raji Subramanian
IPv4 Features
1. Invented to support the Pentagon and select Universities
2. Ensures address uniqueness on the Internet and on the Intranet
3. Permits address sharing using Network Address Translation (NAT) via IPv4 Multiplexing. Note: IPv4 at layer-4 support 65536 ports per protocol:
a. TCP - 0-65535
b. UDP - 0-65535
4. Supports 2^32 or approximately 4.3 billion addresses
5. IPv4 is a 32-bit addressing system
Note: Computers are binary or base-2 systems. i.e. (0 or 1)
6. Represents addresses using 4-bytes (32-bits) or 4-Octets
Note: 1-Octet = 8-bits = 1-byte
7. Uses Classful (A-E)
8. Uses Classless (CIDR) notation - i.e. /24 = 24-bits or 255.255.255.0
9. Standardized in September, 1981 via RFC-791
10. IPv4 consists of a 20-to-60-byte variable length header
11. Fragmentation is performed by routers
12. Options are embedded in the IP packet, resulting in variable lenghts
13. Subnet mask is used to distinguish between networks and hosts
14. IPv4 uses broadcasts heavily - i.e. ARP
15. Configuration depends heavily on manual(Static) or DHCP(Dynamic)
16. Provides ICMP for debugging. i.e. PING, traceroute, mtr, etc.
17. Multicast is optional
IPv6 Features:
1. Increased address space to 128-bits vs. 32-bits
2. /48 or 48-bits are assigned to the organization and is globally unique
3. /16 is used for organizational subnetting - 16-bits
4. /64 to define unique hosts per subnet
5. Minimum 1280-byte MTU compared to 576-byte MTU for IPv4
6. Automatic Configuration is now a reality:
a. Link-local address is auto-configured
b. Router Solicitation is performed by IPv6 hosts
c. DHCPv6 Solicitation is performed by IPv6 hosts
7. 2-Types of Address Configurations:
a. Stateless - without DHCPv6 server and/or router - uses multicast
b. Stateful - with DHCPv6 server and/or router
8. Routers pass along prefixes to be auto-configured on IPv6 hosts
9. DHCPv6 servers pass along prefixes and/or additional settings
10. IPv6 obviates the need for NAT because ALL hosts/devices are assigned a Globally Uniqued ID (GUID)
11. Supports 3-Types of addresses:
a. Unicast - unique address for a device (host/router/phone/etc.)
b. Multicast address - groups common systems (routers/hosts/etc.)
c. Anycast address - represents closest address, especially in multihomed environments
12. IPv6 hosts uses Neighbor Discovery (ND) over multicast to find hosts
13. ND replaces ARP and other broadcast-based techniques
14. Facilitates hierarchial routing from Internet backbone to the farthest regions of an organization's networks
INTERNET BACKBONE
-ISP
-Organization
-Organization's Subnets
15. IPv6 uses Hexadecimal to represent the 128-bit addresses because HEX is base-16, and requires less space to note addresses
16. IPv6 supports JumboGrams - packets larger than 64k
17. IPv6 segments 128-bit address into 16, 8-bit fields or 16-Octets
18. IPSEC - provides data integrity and encryption services
19. Each HEX value represents a nibble (4-bits) or half byte
inet6 addr: fe80::211:43ff:fe5a:bce5/64 Scope:Link
inet addr:192.168.75.15 Bcast:192.168.75.255 Mask:255.255.255.0