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Showing posts from May 20, 2012

1.4.13 IPv4 vs. IPv6

IPv4 vs. IPv6 Internet Protocol (IP) is a global communications standard used for linking devices together. It defines how computers communicate over a network. The primary purpose of an IP address is to uniquely identify a node at the Network Layer. Every Internet connected device, computer, smartphone, smart TV, etc. needs a unique IP address. The explosive growth in mobile devices including mobile phones, notebook computers, and wireless handheld devices has created a need for a large number of additional IP addresses. There are currently two versions: IP version 4 (IPv4) and IP version 6 (IPv6). IPv4 is the 4th version of the Internet Protocol. It is the most commonly deployed OSI Layer 3 (Network layer) protocol. IPv4 has a 32 bit address space and consists of 2 32 or approximately 4.3 billion possibile IPv4 addresses. IPv4 was formally defined by the Internet Engineering Task Force (IETF) in September 1981 as RFC-791. IPv6 is the next generation of the Internet Protoc

1.4.12 ICMP

ICMP Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet Protocol Suite. It provides maintenance and reporting functions. It is chiefly used by IP end systems and all IP intermediate systems (i.e routers) to send error messages indicating, problems with delivery of IP datagrams within an IP network. It can be used to show when a particular end system is not responding, when an IP network is not reachable, when a node is overloaded, when an error occurs in the IP header information, etc. The Internet Protocol is not designed to be absolutely reliable. The purpose of these control messages is to provide feedback about problems in the communication environment, not to make IP reliable. The higher level protocols that use IP must implement their own reliability procedures if reliable communication is required. ICMP is defined in RFC 792. It is assigned protocol number 1. ICMP provides error reporting, flow control and first-hop gateway redirection.