1.7. Used terms, glossary and shortcuts

Well known decimal number system, represent any value with digit 0-9.

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).

Representation of a value with 85 different digits/chars, this can lead to shorter strings but never seen in the wild.

Smallest storage unit, on/true (1) or off/false (0)

Mostly a collection of 8 (but not really a must - see older computer systems) bits

Here, hardware of network connection, see also NIC

A 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.

Generally a single homed host on a link. Normally it has only one active network interface, e.g. Ethernet or (not and) PPP.

Mostly same as “device”, see also NIC

Header of an IP packet (each network packet has a header, kind of is depending on network layer)

A link is a layer 2 network packet transport medium, examples are Ethernet, Token Ring, PPP, SLIP, ATM, ISDN, Frame Relay,...

A node is a host or a router.

A collection of 8 real bits, today also similar to “byte”.

Information for the TCP/UDP dispatcher (layer 4) to transport information to upper layers

Each 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)

A router is a node with two or more network (physical or virtual) interfaces, capable of forwarding packets between the interfaces.

An IP socket is defined by source and destination IP addresses and Ports and (binding)

Network related a collection of layers

IP networks uses bit masks to separate local networks from remote ones

A tunnel is typically a point-to-point connection over which packets are exchanged which carry the data of another protocol, e.g. an IPv6-in-IPv4 tunnel.