Specifications

AVM Access Server – Glossary 127
IP (Internet Protocol)
IP is the Network Layer protocol responsible for addressing and routing
in the TCP/IP protocol family. In general terms, its purpose is to provide
data communication between various networks. IP provides:
data packet transmission
fragmentation of data
selection of communication parameters
addressing
routing between networks
identification of higher-order protocols
IP does not provide assured transmission: the sender receives no veri-
fication that the packet was delivered. End-to-end transmission control
is left to the higher-layer protocols. Lost or rejected packets are not re-
transmitted. IP also makes no provision for sequence integrity of the
packets: they may arrive at the receiver in any order. Sequence integri-
ty is likewise left to the OSI model Layer 4, the Transport Layer.
IP builds directly on OSI Layer 2, the Data Link Layer. The Internet Pro-
tocol is described in RFC 791.
IP address
Addressing is one of the main functions of the Internet Protocol (IP). Ad-
dresses in IP version 4 are 32-bit numbers, which can be written as four
bytes in decimal, octal or hexadecimal notation. In the AVM Access Server
configuration, “dotted-decimal” notation is used: the four bytes of an IP
address are represented by decimal numbers separated by dots. The full
set of IP addresses, called the address space, is grouped into address
classes designated as A, B, C, D and E. Only the first three address classes
are actually used. These classes can be described as follows:
IP address classes
Class Characteristics First byte of network
address (decimal)
Class A addresses
Few networks with many nodes 0-127
Class B
addresses
Medium number of networks
and medium number of nodes
128-191
Class C addresses Many networks with few
nodes
192-223