![]() Looking back into the past, 32 bits were enough until now and will perhaps be enough for another few years. IPv6 addresses: why such a high number of bits?ĭuring the design of IPv4, people thought that 32 bits were enough for the world. ![]() Info: ipv6calc is an IPv6 address format calculator and converter program and can be found here: ipv6calcĢ.4.2. April 1996), never seen in the wild, probably an April fool's joke, but here is an example: There is also a so-called compact (base85 coded) representation defined RFC 1924 / A Compact Representation of IPv6 Addresses (published on 1. But not more than one at a time, otherwise it is no longer a unique representation.ģffe:ffff:100:f101:0:0:0:1 -> 3ffe:ffff:100:f101::1 One sequence of 16 bit blocks containing only zeroes can be replaced with "::". In addition, the leading "0x" (a signifier for hexadecimal values used in programming languages) is removed:Ģ^128-1: ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffffĪ usable address (see address types later) is e.g.:įor simplifications, leading zeros of each 16 bit block can be omitted:ģffe:ffff:0100:f101:0210:a4ff:fee3:9566 -> This representation is still not very convenient (possible mix-up or loss of single hexadecimal digits), so the designers of IPv6 chose a hexadecimal format with a colon as separator after each block of 16 bits. This format reduces the length of the IPv6 address to 32 characters.Ģ^128-1: 0xffffffffffffffffffffffffffffffff In hexadecimal, 4 bits (also known as "nibble") are represented by a digit or character from 0-9 and a-f (10-15). Therefore a better notation of such big numbers is hexadecimal. Also the IPv6 address schema is bitwise orientated (just like IPv4, but that's not often recognized). Such numbers are not really addresses that can be memorized. an IPv6-in-IPv4 tunnel.Īs previously mentioned, IPv6 addresses are 128 bits long. IP networks uses bit masks to separate local networks from remote onesĪ tunnel is typically a point-to-point connection over which packets are exchanged which carry the data of another protocol, e.g. Information for the TCP/UDP dispatcher (layer 4) to transport information to upper layersĮach network layer contains mostly a protocol field to make life easier on dispatching transported information to upper layer, seen in layer 2 (MAC) and 3 (IP)Ī router is a node with two or more network (physical or virtual) interfaces, capable of forwarding packets between the interfaces.Īn IP socket is defined by source and destination IP addresses and Ports and (binding) Header of an IP packet (each network packet has a header, kind of is depending on network layer)Ī link is a layer 2 network packet transport medium, examples are Ethernet, Token Ring, PPP, SLIP, ATM, ISDN, Frame Relay.Ī collection of 8 real bits, today also similar to "byte". Normally it has only one active network interface, e.g. Here, hardware of network connection, see also NICĪ dual homed host is a node with two network (physical or virtual) interfaces on two different links, but does not forward any packets between the interfaces. Mostly a collection of 8 (but not really a must - see older computer systems) bits Smallest storage unit, on/true (1) or off/false (0) Representation of a value with 85 different digits/chars, this can lead to shorter strings but never seen in the wild. Usually used in lower and higher programming languages, known also as hexadecimal number system, represent any value with digit 0-9 and char A-F (case insensitive). Well known decimal number system, represent any value with digit 0-9. Revision history / Credits / The End 24.1. Paper printed books, articles, online reviews (mixed) 23.2. ![]() ![]() Router Advertisement Daemon (radvd) 20.5. Berkeley Internet Name Daemon BIND (named) 20.2. Dynamic Host Configuration Protocol v6 (DHCPv6) 15.4. Stateful auto-configuration using Router Advertisement Daemon (radvd) 15.3. Support for persistent IPv6 configuration in Linux distributions 14.1. IPv6-related entries in /proc/sys/net/ipv4/ 11.4. Kernel settings in /proc-filesystem 11.1. Manipulating neighbors table using "ip" 9. Removing an IPv6 route through an interface 7.6. Add an IPv6 route through an interface 7.5. Removing an IPv6 route through a gateway 7.4. IPv6-ready client programs (selection) 4.6. IPv6-ready network configuration tools 4.3.
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