The Internet architecture is also frequently referred to as the TCP/IP architecture, after its most well-known protocols. TCP/IP protocols are the most widely used communication protocols in networks.
Like the OSI architecture, the Internet architecture has a definite layer structure in the transport system; the Application Layer, on the other hand, is more function- or serviceoriented, like the NEA architecture.
IPv6 represents a further development of the TCP/IP architecture and provides a basis for high-performance, easy-to-administer, scalable communications during the coming decades.
Practical experience of IPv4 has made it possible to eliminate shortcomings and implement additional features. Alongside the extension of the address space, the packet format has also been simplified.
The setting up and administration of IPv6 networks has also been simplified.
Particular attention has also been paid to ensuring a smooth transition from IPv4 networks to IPv6 networks.
You can obtain the RFCs listed below, which provide the basis of the IPv6 functionality, at http://www.rfc-editor.org/.
Thomson, S., T. Narten, T. Jinmei, IPv6 Stateless Address Autoconfiguration, RFC 4862, September 2007.
Nichols, K., S. Blake, F. Baker, and D. Black, Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers, RFC 2474, December 1998.
Ramakrishnan, K., S. Floyd, and D. Black, The Addition of Explicit Congestion Notification (ECN) to IP, RFC 3168, September 2001.
Conta, A., S. Deering M. Gupta, Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification, RFC 4443, March 2006.
Hinden, R., S. Deering, Internet Protocol, Version 6 Addressing Architecture, RFC 4291, February 2006.
Hinden, R., S. Deering, Internet Protocol, Version 6 (IPv6) Specification, RFC 2460, December 1998.
Narten, T., Nordmark, E., and W. Simpson, H. Soliman, Neighbor Discovery for IP Version 6 (IPv6), RFC 4861, September 2007.
McCann, J., S. Deering, and J. Mogul, Path MTU Discovery for IPv6, RFC 1981, August 1996.
Abley. J, Savola, P. Neville-Neil, G. Deprecation of Type 0 Routing Headers in IPv6, RFC 5095, December 2007
OSI Layer | Function | Internet protocols |
Layer 5 - 7 | Application Layer | TELNET, FTP, SMTP |
Layer 4 | Transport Layer | TCP, UDP |
Layer 3 | Network Layer | IP, ARP *, ICMP * |
Layer 2 | Subnetwork Layer | SNAP, LLC1/2 |
Layer 1 |
Protocols of the Internet architecture
The protocols marked with * are administration protocols
Subnetwork Layer
The CSMA/CD (Carrier Sense Multiple Access / Collision Detection) procedure is used in the Subnetwork Layer, e.g. in Ethernet. This means that all stations are connected to a shared bus and have the same access authorization to the line. Before transmission, the station checks whether the LAN is free. If the station identifies that the network is free, it begins the transmission. If a number of stations begin transmission at the same time, collisions will occur. In this case, the stations start transmitting again at different dimes. The send time of the individual station is determined by a random generator. The 48-bit Ethernet address is used for addressing within the subnetwork.
Network Layer
IP (Internet Protocol) is the most important protocol in the Network Layer. The main task of IP is system addressing. IP provides connectionless transmission of datagrams between two systems without error recovery. The addressing occurs via the world-wide unique 32-bit Internet address. For a detailed explanation of addressing, refer to section "IPv4 addresses".
In the further developed IPv6 protocol, addressing is performed via the world-wide unique 128-bit IPv6 address. For a detailed explanation of addressing, refer to section "IPv6 addresses".
ARP (Address Resolution Protocol) is used to map an Internet address onto an Ethernet address. This function can only be offered for systems which are found in the same physical subnetwork. RARP (Reverse Address Resolution Protocol) has the opposite function for the gateway to the network layer. However, RARP is no longer of any practical significance
ICMP (Internet Control Message Protocol) sends error and control messages to other hosts, and controls the communication of Internet software between network computers.
ICMPv6 (Internet Control Message Protocol) contains additional mechanisms for the detection of end systems and routers, for end system and router failure detection (“Neighbor Discovery”) and for the automatic generation of local IPv6 addresses (“Autoconfiguration”).
IP Security
If you use the optional IPSec V1.n and CRYPT V1.n, you can use the security extensions of the IP protocol, which can be used in every application.
Authentication Header (AH) provides access to functions for protection against corrupt data (authenticity).
Encapsulated Security Payload (ESP) provides access to:
functions for protection against corrupt data (integrity)
mechanisms for data encryption (confidentiality).
Transport Layer
TCP is the connection-oriented protocol of the Transport Layer. TCP provides data for security and the mechanisms for flow control.
BCAM provides additional support of ECN protocol functions (Explicit Congestion Notification) according to RFC 3168.
With these compatible protocol extensions in TCP and IP, router end systems can detect jam situations at an early stage. In this way the loss of segments can be prevented and performance can be considerably improved.
ECN support is activated in BCAM (as required in RFC 3168) by default. The use of the function is handled between the partner systems during TCP connection establishment.If required, a route-specific or global shutdown can be carried out using the MODIFY-ROUTE-ATTRIBUTES command.
UDP is the connectionless protocol of the Transport Layer. Data losses and transmission errors are not detected or reported by this protocol.
TCP and UDP use unambiguous port numbers for addressing.